<entry linktype="AI" linkname="EUR-001-001" title="Figure 1.1: Various steps of the paraffin method">The various steps involved in producing a histologic slide using the paraffin method. 1. Removing Organ Sample 2. Cutting Small Pieces 3. Prepairing Speicmens for Sectioning 4. Sectioning with Microtome 5. Straightening Sections on Waterbath 6. Transferring Sections to Slide 7. Drying on Warmer 8. Staining 9. Coverslipping Fix Dehydrate Clear Embed Mold with Specimen Melted Paraffin Paraffin Block Removed from Mold Trimmed Block </entry>
<entry linktype="AI" linkname="EUR-001-002" title="Figure 1.2: Examples of slices and sections on slides">A. Slices, indicated by numbered planes, taken through two different types of cells would appear as identified by the prime numbers. Only if the plane of the cut passes through the nucleus will the latter be seen. B and C. Planes of section taken from different levels in four separate multicellular objects are illustrated. Note how the appearance of sections varies with the level of the cut.</entry>
<entry linktype="AI" linkname="EUR-001-003" title="Figure 1.3: Examples of cuts at different levels">The prime numbers illustrate sections resulting from transverse (4), oblique (1), and longitudinal (2, 3, 5, 6) cuts made through a plate of cells bearing hollow projections (above plate) and invaginations (below plate). Plane 3 differs from the others because it passes only through the cellular wall of a projection, and not the lumen; therefore, section 3' appears as a plate of cells rather than a hollow structure. You should also be aware that structures may often appear unrelated to a surface or another object, when in fact they are. Compare planes 5 and 6 with sections 5' and 6', where continuity of the invagination with the surface is evident only in 6 and 6′. While not apparent from a single section, such continuity would be evident if an uninterrupted series of sections through the entire invagination were made and examined.</entry>
<entry linktype="AI" linkname="EUR-001-004" title="Figure 1.4: Vernier scales">Small and large vernier scales.</entry>
<entry linktype="AI" linkname="EUR-001-005" title="Figure 1.5: Stain Precipitate, Cartilage, Dog">Stain Precipitate, Cartilage, Dog. Occasionally, solutions accumulate precipitate that may stick to the surface of tissue sections during the staining procedure. Stain precipitate Stain precipitate </entry>
<entry linktype="AI" linkname="EUR-001-006" title="Figure 1.6: Separation (Space) Artifact, Skin, Dog">Separation (Space) Artifact, Skin, Dog. Tissues may be subjected to excessive pressures, tensions, or shrinkage during processing, resulting in separations within otherwise intact tissue. Epidermis Dermis Separation artifact Separation artifact </entry>
<entry linktype="AI" linkname="EUR-001-007" title="Figure 1.7: Crackling Artifact, Thymus, Horse">Crackling Artifact, Thymus, Horse. Highly cellular tissues, for example, thymus, liver, pancreas, and spleen, often show numerous tiny cracks throughout. Also note that this specimen is not in sharp focus.</entry>
<entry linktype="AI" linkname="EUR-001-008" title="Figure 1.7: Crackling Artifact, Thymus, Horse">Knife Marks and Folds, Esophagus, Horse (MassonÕs). Knife marks (scratches) in the tissue section may be caused by defects in the microtome knife or by accumulations of debris on the knife edge. Folds occur when the tissue sections fail to spread properly on the surface of the slide. Fold Knife mark Knife mark </entry>
<entry linktype="AI" linkname="EUR-001-009" title="Figure 1.9: Fold, Aorta, Pig">Fold, Aorta, Pig. In a tissue section, folds are raised areas that frequently overlap. Note that portions of this picture are not in sharp focus. Fold Fold </entry>
<entry linktype="AI" linkname="EUR-002-002" title="Figure 2.2: Simple Squamous Epithelium of Blood Vessels and Lymphatic Vessels, Submucosa of the Stomach, Pig">Simple Squamous Epithelium of Blood Vessels and Lymphatic Vessels, Submucosa of the Stomach, Pig. Blood vessels and lymphatic vessels (and the heart) are lined by a simple squamous epithelium that is specifically called an endothelium in those locations. The cytoplasm of the squamous cells is sparse, and generally only the nucleus is visible. Characteristically, the nuclei appear flat in histologic section. If the squamous cells are bunched up, such as those lining a vessel that is contracted, their nuclei appear round. Collagenous fiber Blood vessel, lumen Fibroblast, nucleus Squamous cell, nucleus Smooth muscle cell, nucleus Smooth muscle cell, nucleus Fibroblast, nucleus Smooth muscle cell, nucleus Collagenous fiber Squamous cell, nucleus Blood vessel, lumen Squamous cell, nucleus Squamous cell, nucleus Squamous cell, nucleus Lymphatic vessel, lumen Squamous cell, nucleus Squamous cell, nucleus</entry>
<entry linktype="AI" linkname="EUR-002-003" title="Figure 2.3: Simple Squamous Epithelium, Kidney, Sheep">Simple Squamous Epithelium, Kidney, Sheep. The outer layer of Bowman's capsule of a renal corpuscle is called the parietal layer. It is formed by a single layer of squamous cells. A magnified example of the parietal layer of Bowman's capsule is shown in Figure 2.4. Tubules lined by a simple cuboidal epithelium are evident. Cuboidal cell, nucleus Tubule, lumen Cuboidal cell, nucleus Squamous cell, nucleus Urinary space Squamous cell, nucleus Cuboidal cell, nucleus Tubule, lumen</entry>
<entry linktype="AI" linkname="EUR-002-004" title="Figure 2.4: Simple Squamous Epithelium, Kidney, Sheep">Simple Squamous Epithelium, Kidney, Sheep. The flat nuclei of the squamous cells of the parietal layer of Bowman's capsule are visible, forming the outer lining of the urinary space of the renal corpuscle. Cuboidal cell, nucleus Squamous cell, nucleus Urinary space Squamous cell, nucleus Squamous cell, nucleus Tubule, lumen Cuboidal cell, nucleus Tubule, lumen Squamous cell, nucleus </entry>
<entry linktype="AI" linkname="EUR-002-005" title="Figure 2.5: Simple Squamous Epithelium, Mesothelium, Liver">Simple Squamous Epithelium, Mesothelium, Liver, Cat. The surface of the liver is covered by a single layer of squamous cells. Mesothelium is a specific term for the epithelium of the serous membranes of the body, namely the peritoneum, pleura, and pericardium. Squamous cell, nucleus Squamous cell, nucleus Connective tissue Hepatocytes </entry>
<entry linktype="AI" linkname="EUR-002-006" title="Figure 2.6: Simple Cuboidal Epithelium, Kidney, Cow (Trichrome)">Simple Cuboidal Epithelium, Kidney, Cow (Trichrome). The lining of the tubules shown here consists of a single layer of cuboidal cells. Cuboidal cell, nucleus Tubule, lumen Cuboidal cell, nucleus Tubule, lumen </entry>
<entry linktype="AI" linkname="EUR-002-007" title="Figure 2.7: Simple Cuboidal and Simple Squamous Epithelium, Medulla of Kidney, Sheep">Simple Cuboidal and Simple Squamous Epithelium, Medulla of Kidney, Sheep. The boundaries between the cuboidal cells are not distinct in the tubules lined by simple cuboidal epithelium in this image. To determine the shape of the cells, imagine drawing lines between the nuclei of adjacent cells to approximate their borders. Note the simple squamous epithelium that lines the capillaries and the thin segments of the loop of Henle. Cuboidal cell, nucleus Tubule, lumen Cuboidal cell, nucleus Cuboidal cell, nucleus Squamous cell, nucleus Cuboidal cell, nucleus Tubule, lumen Squamous cell, nucleus Squamous cell, nucleus </entry>
<entry linktype="AI" linkname="EUR-002-008" title="Figure 2.8: Simple Columnar Epithelium, Pyloric Stomach, Cat">Simple Columnar Epithelium, Pyloric Stomach, Cat. This low power view shows the location of the simple columnar epithelium that lines the lumen of the stomach and invaginates to form gastric pits. Figure 2.9 is a magnified view of the epithelium of the stomach similar to the area outlined by the rectangle in this image. Stomach, lumen Simple columnar epithelium Similar area magnified in Figure 2.9 Gastric pit, lumen Simple columnar epithelium Lamina propria Gastric gland Smooth muscle tissue </entry>
<entry linktype="AI" linkname="EUR-002-009" title="Figure 2.9: Simple Columnar Epithelium, Pyloric Stomach, Dog">Simple Columnar Epithelium, Pyloric Stomach, Dog. The columnar cells that line the lumen of the stomach and the gastric pits have apical cup-shaped regions that contain mucus precursor in living tissue. Note the elongated nuclei that are typical of columnar cells. Stomach, lumen Stomach, lumen Columnar cell, nucleus Mucus precursor region Columnar cell, nucleus Lamina propria Simple columnar epithelium Simple columnar epithelium Gastric pit, lumen </entry>
<entry linktype="AI" linkname="EUR-002-010" title="Figure 2.10: Simple Columnar Epithelium, Jejunum, Dog">Simple Columnar Epithelium, Jejunum, Dog. The jejunum is lined by a simple columnar epithelium. A striated border that consists of numerous microvilli is evident. Goblet cells and migrating lymphocytes are present among the columnar cells. In the upper part of this image, the simple columnar epithelium was cut obliquely, making it appear atypical. Lamina propria Simple columnar epithelium Jejunum, lumen Lymphocyte Columnar cell, nucleus Goblet cell Striated border </entry>
<entry linktype="AI" linkname="EUR-002-011" title="Figure 2.11: Ciliated Pseudostratified Columnar Epithelium, Trachea, Sheep">Ciliated Pseudostratified Columnar Epithelium, Trachea, Sheep. A pseudostratified columnar epithelium is formed by a single layer of cells of different sizes whose nuclei are at different levels, so that the epitheliums appear stratified. However, it is a simple epithelium because all of the epithelial cells contact the basement membrane, although this relationship is not visible. Trachea, lumen Pseudostratified columnar epithelium Lamina propria Cilia Columnar cell, nucleus Collagenous fiber </entry>
<entry linktype="AI" linkname="EUR-002-012" title="Figure 2.12: Ciliated Pseudostratified Columnar Epithelium, Trachea, Cow">Ciliated Pseudostratified Columnar Epithelium, Trachea, Cow. Goblet cells are evident in this example of a pseudostratified columnar epithelium. Trachea, lumen Pseudostratified columnar epithelium Goblet cell Columnar cell, nucleus Collagenous fiber Columnar cell, nucleus Basement membrane Cilia Lamina propria </entry>
<entry linktype="AI" linkname="EUR-002-013" title="Figure 2.13: Stratified Squamous Epithelium, Nonkeratinized, Epiglottis, Goat">Stratified Squamous Epithelium, Nonkeratinized, Epiglottis, Goat. Only cells of the basal layer of a stratified epithelium contact the basement membrane. In a nonkeratinized epithelium, the nuclei of the cells are visible throughout the epithelium, even those of the most superficial cells. Note the simple squamous epithelium that lines the lymphatic vessel in the underlying connective tissue. Pharynx, lumen Stratified squamous epithelium Squamous cell, nucleus Lamina propria Lymphatic vessel, lumen Squamous cell, nucleus Collagenous fiber </entry>
<entry linktype="AI" linkname="EUR-002-014" title="Figure 2.14: Stratified Squamous Epithelium, Nonkeratinized, Esophagus, Cat">Stratified Squamous Epithelium, Nonkeratinized, Esophagus, Cat. A nonkeratinized stratified squamous epithelium is visible lining the collapsed lumen of the esophagus. Lamina propria Stratified squamous epithelium Squamous cell, nucleus Esophagus, lumen Lamina propria Stratified squamous epithelium Squamous cell, nucleus </entry>
<entry linktype="AI" linkname="EUR-002-015" title="Figure 2.15: Stratified Squamous Epithelium, Keratinized, Skin of Scrotum, Sheep">Stratified Squamous Epithelium, Keratinized, Skin of Scrotum, Sheep. The superficial layer of the keratinized stratified squamous epithelium is formed by dead, keratinized cells that appear as thin strands, without visible nuclei, separated from one another. Compare the keratinized cells here with the superficial cells in the nonkeratinized epithelium in Figures 2.13 and 2.14. Keratinized cells Stratified squamous epithelium Dermis Keratinized cells </entry>
<entry linktype="AI" linkname="EUR-002-016" title="Figure 2.16: Stratified Squamous Epithelium, Keratinized, Wattle, Pig">Stratified Squamous Epithelium, Keratinized, Wattle, Pig. The wattle is covered by a keratinized stratified squamous epithelium. Keratinized cells Stratified squamous epithelium Separation artifact Dermis </entry>
<entry linktype="AI" linkname="EUR-002-017" title="Figure 2.17: Bistratified Cuboidal Epithelium, Esophagus, Dog">Bistratified Cuboidal Epithelium, Esophagus, Dog. This duct of an esophageal gland is lined by a bistratified cuboidal epithelium. Smooth muscle tissue Bistratified cuboidal epithelium Collagenous fiber </entry>
<entry linktype="AI" linkname="EUR-002-018" title="Figure 2.18: Bistratified Columnar Epithelium, Duct of Carpal Gland, Pig">Bistratified Columnar Epithelium, Duct of Carpal Gland, Pig. This duct is lined by a bistratified columnar epithelium. Note the columnar-shaped apical cells (the cells bordering the lumen) with elongated nuclei. A simple squamous epithelium lines the longitudinal section of a capillary that is visible in this field. Collagenous fibers Bistratified columnar epithelium Duct, lumen Columnar cell, nucleus Squamous cell, nucleus Capillary, lumen </entry>
<entry linktype="AI" linkname="EUR-002-019" title="Figure 2.19: Stratified Columnar Epithelium, Urethra, Goat">Stratified Columnar Epithelium, Urethra, Goat. This portion of the urethra is lined by a stratified columnar epithelium. The surface cells of this stratified epithelium are columnar. Urethra, lumen Stratified columnar epithelium Collagenous fibers Columnar cell, nucleus </entry>
<entry linktype="AI" linkname="EUR-002-020" title="Figure 2.20: Transitional Epithelium, Unstretched, Urinary Bladder, Pig">Transitional Epithelium, Unstretched, Urinary Bladder, Pig. A transitional epithelium lines the lumen of the bladder as well as other parts of the urinary system. Surface cells of the transitional epithelium are either balloon-shaped or broadly cuboidal when not under tension. Urinary bladder, lumen Transitional epithelium Collagenous fibers Smooth muscle tissue </entry>
<entry linktype="AI" linkname="EUR-002-021" title="Figure 2.21: Transitional Epithelium, Unstretched, Urinary Bladder, Cat">Transitional Epithelium, Unstretched, Urinary Bladder, Cat. Note the large rounded surface cells in this unstretched transitional epithelium. Urinary bladder, lumen Transitional epithelium </entry>
<entry linktype="AI" linkname="EUR-002-022" title="Figure 2.22: Transitional Epithelium, Stretched, Urinary Bladder, Cat">Transitional Epithelium, Stretched, Urinary Bladder, Cat. Surface cells of this epithelium are flattened and elongated when the bladder is stretched with urine. Urinary bladder, lumen Transitional epithelium </entry>
<entry linktype="AI" linkname="EUR-002-023" title="Figure 2.23">Surface View, simple squamous epithelium The line indicates the plane of the cut. Surface View, simple squamous epithelium. The line indicates the plane of the cut. </entry>
<entry linktype="AI" linkname="EUR-002-024" title="Figure 2.24">Profile View, as seen in a histologic section Profile View, as seen in a histologic section </entry>
<entry linktype="AI" linkname="EUR-003-001" title="Figure 3.1: Mesenchyme, 72-Hour Embryo, Chicken">Mesenchyme,72-Hour Embryo, Chicken. Mesenchyme consists of stellate cells. Their processes touch, forming a three-dimensional latticework. The cells are surrounded by an amorphous ground substance. Mesenchyme cell Amorphous ground substance </entry>
<entry linktype="AI" linkname="EUR-003-002" title="Figure 3.2: Mucous Connective Tissue, Umbilical Cord, Cow">Mucous Connective Tissue, Umbilical Cord, Cow. Mucous connective tissue consists of a loose framework of fibroblasts and collagenous fibers in an amorphous ground substance. Mucous connective tissue of the umbilical cord is often called Wharton's jelly. Fibroblast nucleus Amorphous ground substance Collagenous fiber </entry>
<entry linktype="AI" linkname="EUR-003-003" title="Figure 3.3: Loose Connective Tissue, Mesentery, Cat (LeukoStat and orcein)">Loose Connective Tissue, Mesentery, Cat (LeukoStat and orcein). The loose arrangement of the connective tissue cells and fibers in this whole mount preparation is evident. Fine, branching elastic fibers appear blue-gray. The thicker, collagenous fibers stain pale pink. Note the mast cell filled with purple granules. Mast cell Elastic fiber Collagenous fiber Erythrocytes in capillary Fibroblast nucleus Fibroblast nucleus </entry>
<entry linktype="AI" linkname="EUR-003-004" title="Figure 3.4: Plasma Cells, Loose Connective Tissue, Lamina Propria, Jejunum, Dog">Plasma Cells, Loose Connective Tissue, Lamina Propria, Jejunum, Dog. Plasma cells are common constituents of the lamina propria of the gastrointestinal tract. They are characterized by a basophilic cytoplasm and large blocks of nuclear heterochromatin. A lightly stained area adjacent to the usually eccentric nucleus marks the location of the Golgi apparatus. Fibroblast nucleus Lymphocyte Plasma cell Neutrophil Plasma cell Collagenous fiber Eosinophil </entry>
<entry linktype="AI" linkname="EUR-003-005" title="Figure 3.5: Mast Cells, Loose Connective Tissue, Lip, Cat (Toluidine Blue)">Mast Cells, Loose Connective Tissue, Lip, Cat (Toluidine Blue). The granules of mast cells are metachromatic and are colored purple by toluidine blue. Epithelium, lipl Fibroblast nucleus Mast cell Mast cell Fibroblast nucleus </entry>
<entry linktype="AI" linkname="EUR-003-006" title="Figure 3.6: Loose Connective Tissue, Lamina Propria, Duodenum, Cow">Loose Connective Tissue, Lamina Propria, Duodenum, Cow. A loose meshwork of fibers of the connective tissue and various cells are contained in an amorphous, ground substance. Globular leukocyte Fibroblast nucleus Eosinophil Fibroblast nucleus Globular leukocyte Plasma cell Eosinophil Eosinophil Lymphocyte Lymphocyte Plasma cell Mast cell Fibroblast nucleus Collagenous fiber </entry>
<entry linktype="AI" linkname="EUR-003-007" title="Figure 3.7: Macrophages, Loose Connective Tissue, Colon, Pig">Macrophages, Loose Connective Tissue, Colon, Pig. Wandering macrophages are characterized by their oval shape. The cytoplasm of these cells often contains ingested particles and appears dirty. Eosinophils of the pig contain oval or bilobed nuclei. Macrophage Collagenous fiber Adipocyte Macrophage Eosinophil Eosinophil Collagenous fiber </entry>
<entry linktype="AI" linkname="EUR-003-008" title="Figure 3.8: Loose and Dense Irregular Connective Tissue, Dermis, Planum Nasolabiale, Cow">Loose and Dense Irregular Connective Tissue, Dermis, Planum Nasolabiale, Cow. Note that the loose connective tissue of the papillary layer of the dermis contains finer fibers and more cells than the dense irregular connective tissue of the reticular layer. Epithelium, planum Loose connective tissue Collagenous fiber Fibroblast nucleus Fibroblast nucleus Collagenous fiber Collagenous fiber Dense irregular connective tissue Collagenous fiber Fibroblast nucleus </entry>
<entry linktype="AI" linkname="EUR-003-010" title="Figure 3.10: Dense Regular Connective Tissue, Tendon, x.s. and l.s., Nose, Pig">Dense Regular Connective Tissue, Tendon, x.s. and l.s., Nose, Pig. In tendons and ligaments, collagenous fibers are arranged in parallel order. Fibroblasts are located between the fibers. Tendon, l.s. Tendon, x.s. Fibroblast nucleus Fibroblast nucleus Tendon, l.s. Tendon, x.s. Fibroblast nucleus Fibroblast nucleus </entry>
<entry linktype="AI" linkname="EUR-003-011" title="Figure 3.11: Tendon and Tendon Sheath, x.s., Dog">Tendon and Tendon Sheath, x.s., Dog. The tendon sheath is actually made up of two sheaths. The inner sheath attaches to the surface of the tendon. The outer sheath forms a tube around the tendon and attaches to peripheral structures. The space between the two sheaths is filled with synovial fluid in living tissue. The space is not lined by an epithelium, but rather by collagenous fibers and cells of the connective tissue of the sheaths. Tendon sheath, outer Tendon sheath, inner Tendon, x.s. </entry>
<entry linktype="AI" linkname="EUR-003-012" title="Figure 3.12: Elastic Tissue, Ligamentum Nuchae, l.s., Sheep">Elastic Tissue, Ligamentum Nuchae, l.s., Sheep. This section shows the parallel arrangement of the elastic fibers within the ligament. Elastic fiber Fibroblast nucleus </entry>
<entry linktype="AI" linkname="EUR-003-014" title="Figure 3.14: Reticular Tissue, Lymph Node, Cow (Silver)">Reticular Tissue, Lymph Node, Cow (Silver). Networks of reticular fibers have been blackened by silver. Lymphocyte Lymphocyte Reticular fiber Reticular fiber </entry>
<entry linktype="AI" linkname="EUR-003-015" title="Figure 3.15: Adipose Tissue, Soft Palate, Cow">Adipose Tissue, Soft Palate, Cow. Lipid content of each adipocyte (unilocular) was removed during processing, leaving an empty cavity surrounded by a thin rim of cytoplasm. Nuclei occur at the periphery of adipocytes. It is sometimes difficult to distinguish their nuclei from those of other cells of the connective tissue. See Figure 12.103 for an example of multilocular adipocytes. Adipocyte Adipocyte </entry>
<entry linktype="AI" linkname="EUR-004-001" title="Figure 4.1: Hyaline Cartilage, Trachea, Cat">Hyaline Cartilage, Trachea, Cat. Hyaline cartilage supports the wall of the trachea. Numerous chondrocytes in lacunae are evident in the cartilage. The perichondrium that surrounds the cartilage consists of an outer fibrous layer and an inner chondrogenic layer. The fibrous layer is made of mainly collagenous fibers and fibroblasts. The chondrogenic layer contains precursors of chondrocytes that secrete cartilage matrix. Pseudostratified columnar epithelium Trachea, lumen Chondrocyte Lacuna Perichondrium, fibrous layer Perichondrium, chondrogenic layer Separation artifact Glands Chondrocyte Lacuna Chondrocyte </entry>
<entry linktype="AI" linkname="EUR-004-002" title="Figure 4.2: Hyaline Cartilage, Trachea, Cow">Hyaline Cartilage, Trachea, Cow. The chondrocytes have dark basophilic nuclei surrounded by hazy cytoplasm. Those at the periphery of the cartilage are smaller and flattened; the more central chondrocytes are larger. Numerous isogenous groups of chondrocytes are apparent. Lacunae, evident as white spaces bordering the chondrocytes, are surrounded by dark territorial matrix. The paler interterritorial matrix is more distant from the lacunae. The collagenous fibers in the matrix of hyaline cartilage are not apparent with routine stains. Perichondrium, fibrous layer Perichondrium, chondrogenic layer Chondrocyte Territorial matrix Interterritorial matrix Lacuna Interterritorial matrix Isogenous group Perichondrium, chondrogenic layer </entry>
<entry linktype="AI" linkname="EUR-004-003" title="Figure 4.3: Hyaline Cartilage, Bronchus, Cat">Hyaline Cartilage, Bronchus, Cat. Note the same features as in Figure 4.2. Chondrocyte Territorial matrix Chondrocyte Lacuna Interterritorial matrix Perichondrium, chondrogenic layer Perichondrium, fibrous layer </entry>
<entry linktype="AI" linkname="EUR-004-004" title="Figure 4.4: Elastic Cartilage, Pinna, Dog (Weigert's)">Elastic Cartilage, Pinna, Dog (Weigert's). The pinna (auricle) of the ear consists of elastic cartilage covered by skin. The rectangle outlines the approximate area magnified in Figure 4.5. Elastic cartilage Perichondrium Dermis Area shown in Figure 4.5 </entry>
<entry linktype="AI" linkname="EUR-004-005" title="Figure 4.5: Elastic Cartilage, Pinna, Dog (Weigert's)">Elastic Cartilage, Pinna, Dog (Weigert's). Numerous darkly stained elastic fibers are distinct in the matrix of the elastic cartilage. Because the chondrocytes are quite distorted in this preparation, more of each lacuna is visible. When cartilage is sectioned, the slice may not pass through each chondrocyte, only the space around it, so that lacunae sometimes look empty. Elastic fiber Chondrocyte Lacuna Elastic fiber Perichondrium </entry>
<entry linktype="AI" linkname="EUR-004-006" title="Figure 4.6: Elastic Cartilage, Epiglottis, Dog">Elastic Cartilage, Epiglottis, Dog. In this preparation of elastic cartilage stained with H and E, the elastic fibers visible throughout the matrix are shiny and pink. Elastic fiber Lacuna Chondrocyte Elastic fiber Chondrocyte Elastic fiber Cartilage matrix </entry>
<entry linktype="AI" linkname="EUR-004-007" title="Figure 4.7: Fibrocartilage, Intervertebral Disc, Horse">Fibrocartilage, Intervertebral Disc, Horse. Fibrocartilage is a combination of dense (fibrous) connective tissue and hyaline cartilage. Small chondrocytes in lacunae are arranged in rows and framed by a hazy rim of pale blue cartilage matrix. Lacunae appear as small white halos around the chondrocytes. Collagenous fibers of the dense connective tissue are visible between rows of chondrocytes. Collagenous fiber Chondrocyte Cartilage matrix Chondrocyte Cartilage matrix </entry>
<entry linktype="AI" linkname="EUR-004-008" title="Figure 4.8: Fibrocartilage, Intervertebral Disc, Horse">Fibrocartilage, Intervertebral Disc, Horse. Note the same features as described above in this magnified view of fibrocartilage. Cartilage matrix Chondrocyte Collagenous fiber Lacuna Chondrocyte Cartilage matrix </entry>
<entry linktype="AI" linkname="EUR-004-009" title="Figure 4.9: Fibrocartilage, Claw, Chicken">Fibrocartilage, Claw, Chicken. The numbers and arrangements of collagenous fibers and chondrocytes vary in fibrocartilage. Here, rows of chondrocytes in lacunae are randomly scattered among large bundles of collagenous fibers oriented in various directions. Cartilage matrix Chondrocyte Collagenous fiber Chondrocyte Cartilage matrix </entry>
<entry linktype="AI" linkname="EUR-005-001" title="Figure 5.1: Intramembranous Ossification, Spongy Bone, Decalcified, Nose, Dog">Intramembranous Ossification, Spongy Bone, Decalcified, Nose, Dog. Intramembranous ossification begins in centers of ossification in the embryo, where osteoblasts deposit bone matrix directly within mesenchyme, producing tiny spicules of bone matrix that interconnect with each other to form a latticework of spongy bone. Osteocytes, derived from osteoblasts that become surrounded by bone matrix, can be seen in the forming spicules. Because bone matrix is deposited without a preformed cartilage model during intramembranous ossification, the connected spicules of bone lack cores of calcified cartilage. Osteoclast Lacuna Separation artifact Bone matrix Osteocyte Osteoblast </entry>
<entry linktype="AI" linkname="EUR-005-002" title="Figure 5.2: Intramembranous Ossification, Spongy Bone, Decalcified, Nose, Dog (Masson's).">Intramembranous Ossification, Spongy Bone, Decalcified, Nose, Dog (Masson's). Osteoclasts are multinucleated giant cells present on the surfaces of bone where resorption is occurring. Depressions that form as osteoclasts erode bone matrix are called Howship's lacunae. The spaces between the surface of the bone matrix and the cells that border it are separation artifacts. Osteocyte Lacuna Howship's lacuna Osteoclast Osteoblast Bone matrix Osteoclast Separation artifact </entry>
<entry linktype="AI" linkname="EUR-005-003" title="Figure 5.3: Immature Bone, Phalanx, Decalcified, Fetus, Horse">Immature Bone, Phalanx, Decalcified, Fetus, Horse. There are more osteocytes per unit area in immature bone than in mature bone. Typically, immature bone shows basophilia. Both characteristics are evident in the micrograph. Note the rather even acidophilia of the matrix of the more mature bone. Newly deposited unmineralized bone matrix, osteoid, abuts the surface of the mineralized bone matrix. Mature bone Immature bone Osteoid Osteoblast Osteocyte Mature bone Osteoid </entry>
<entry linktype="AI" linkname="EUR-005-004" title="Figure 5.4: Hyaline Cartilage Model, Developing Long Bone">Hyaline Cartilage Model, Developing Long Bone. Endochondral bone formation in the embryo begins with a model of hyaline cartilage. Hyaline cartilage </entry>
<entry linktype="AI" linkname="EUR-005-005" title="Figure 5.5: Primary Center of Ossification, Developing Long Bone">Primary Center of Ossification, Developing Long Bone. In this sketch, a primary center of ossification has appeared in the center of the cartilage model. The area of the primary center that is outlined (1) is shown in Figure 5.6. A bony periosteal collar has been deposited (by way of intramembranous ossification) around the mid part of the hyaline cartilage model by osteoblasts that formed from cells of the perichondrium, and the perichondrium is now the periosteum. Blood vessels of a periosteal bud have invaded the primary center of ossification, introducing cells that form the bone marrow and give rise to osteoblasts. Periosteum Periosteal collar Periosteal bud Area shown in Figure 5.6 Hyaline cartilage </entry>
<entry linktype="AI" linkname="EUR-005-006" title="Figure 5.6: Primary Center of Ossification, Phalanx, l.s., Decalcified, Fetus, Horse">Primary Center of Ossification, Phalanx, l.s., Decalcified, Fetus, Horse. This section was taken from the central region of a developing phalanx and shows early endochondral ossification. The primary center of ossification in the middle of the hyaline cartilage model is characterized by the presence of chondrocytes that hypertrophy (enlarge) as the cartilage matrix around them becomes reduced. The reduced cartilage matrix consists of tiny pieces with various shapes that become calcified. The enlarged chondrocytes die, leaving spaces that merge and fill with bone marrow. Osteoblasts introduced by blood vessels of the periosteal bud deposit bone matrix (pink) on the meshwork of calcified cartilage matrix (lavender). Hyaline cartilage Calcified cartilage matrix Hypertrophied chondrocyte Bone matrix Marrow cavity Marrow cavity Hypertrophied chondrocyte Calcified cartilage matrix Bone matrix Calcified cartilage matrix Calcified cartilage matrix Hyaline cartilage Hyaline cartilage Calcified cartilage matrix Hypertrophied chondrocyte Bone matrix Marrow cavity Marrow cavity Hypertrophied chondrocyte Calcified cartilage matrix Bone matrix Calcified cartilage matrix Calcified cartilage matrix Hyaline cartilage </entry>
<entry linktype="AI" linkname="EUR-005-007" title="Figure 5.7: Developing Long Bone, l.s.">Developing Long Bone, l.s. This sketch depicts the stage in development of a long bone in which the hyaline cartilage of the diaphysis has been replaced by bony spicules and bone marrow. The epiphyses are still hyaline cartilage. The area outlined with a rectangle (1) approximates that shown in Figure 5.8. Hyaline cartilage in epiphysis Area shown in Figure 5.8 Periosteum Periosteal collar Bony spicule in diaphysis Hyaline cartilage in epiphysis Marrow cavity </entry>
<entry linktype="AI" linkname="EUR-005-008" title="Figure 5.8: Developing Long Bone, l.s., Decalcified, Dog">Developing Long Bone, l.s., Decalcified, Dog. In this developing long bone, the epiphyses are still formed of hyaline cartilage, although the early appearance of secondary centers of ossification is indicated by the presence of blood vessels within the cartilage. Chondrocytes close to the epiphyses have become organized, so that the zones of endochondral ossification are present. Areas similar to those outlined by the rectangles in this image are shown in detail in Figures 5.9 and 5.10. Periosteum Periosteal collar Bony spicule in diaphysis Bone marrow Bony spicule in diaphysis Area shown in Figure 5.10 Area shown in Figure 5.9 Hyaline cartilage in epiphysis Blood vessel </entry>
<entry linktype="AI" linkname="EUR-005-009" title="Figure 5.9: Developing Long Bone, l.s., Decalcified, Dog">Developing Long Bone, l.s., Decalcified, Dog. This magnified view of an area similar to that indicated (2) in Figure 5.8 shows some of the zones of endochondral ossification. The zone of reserve cartilage consists of small chondrocytes. Small, somewhat flattened chondrocytes arranged in stacks mark the zone of multiplication (zone of cell division or proliferation), in which chondrocytes multiply, enabling continued growth of the cartilage. In the zone of hypertrophy, chondrocytes gradually enlarge and the matrix between them becomes reduced. Zone of hypertrophy Zone of multiplication Zone of reserve cartilage Hypertrophied chondrocyte Chondrocyte in lacuna </entry>
<entry linktype="AI" linkname="EUR-005-010" title="Figure 5.10: Developing Long Bone, l.s., Decalcified, Dog">Developing Long Bone, l.s., Decalcified, Dog. This is a magnified view of an area (3) similar to that outlined in Figure 5.8. In the zone of hypertrophy, chondrocytes enlarge. They eventually die, leaving spaces that merge and become occupied by bone marrow. In the zone of calcification, strands of cartilage matrix persist between hypertrophied chondrocytes and become calcified. Osteoblasts from the marrow cavity deposit bone matrix (pink) on the remnants of calcified cartilage matrix (lavender to purple) in the zone of ossification. Megakaryocytes, which produce platelets in the bone marrow, are large cells possessing a large, lobed nucleus. Osteoclasts are also present. Hypertrophied chondrocyte Hypertrophied chondrocyte Zone of hypertrophy Osteoclast Osteoclast Zone of calcification Zone of ossification Calcified cartilage matrix Bone matrix Osteocyte Calcified cartilage matrix Osteoblast Marrow cavity Bone matrix Bony spicule in diaphysis Megakaryocyte Megakaryocyte Sinusoid </entry>
<entry linktype="AI" linkname="EUR-005-011" title="Figure 5.11: Epiphyseal Disc, Developing Long Bone, l.s.">Epiphyseal Disc, Developing Long Bone, l.s. In the stage of a developing long bone represented in this sketch, most of the hyaline cartilage of the epiphyses has been replaced by spongy bone tissue, and hyaline cartilage remains only on the articular surfaces and in the epiphyseal disc (epiphyseal plate). The epiphyseal disc lies between the spongy bone of the epiphysis and the diaphysis. The area outlined by the rectangle approximates that shown in Figure 5.12. Articular cartilage Spongy bone, epiphysis Epiphyseal disc Spongy bone, diaphysis Periosteum Epiphyseal disc Marrow cavity Area shown in Figure 5.12 </entry>
<entry linktype="AI" linkname="EUR-005-012" title="Figure 5.12: Epiphyseal Disc, Humerus, l.s., Decalcified, Cat">Epiphyseal Disc, Humerus, l.s., Decalcified, Cat. This image of the area outlined in Figure 5.11 shows the cartilaginous epiphyseal disc (epiphyseal plate) between the spongy bone of the epiphysis and the diaphysis. Detail of this epiphyseal disc is portrayed in Figure 5.13. Spongy bone, epiphysis Spongy bone, diaphysis Marrow cavity Epiphyseal disc </entry>
<entry linktype="AI" linkname="EUR-005-013" title="Figure 5.13: Epiphyseal Disc, Humerus, l.s., Decalcified, Cat">Epiphyseal Disc, Humerus, l.s., Decalcified, Cat. The various zones of endochondral bone formation can be identified. Small, scattered cartilage cells comprise the zone of reserve (resting) cartilage. They proliferate, forming rows that constitute the zone of multiplication (zone of proliferation). The chondrocytes then enlarge (zone of hypertrophy) and the remaining cartilage matrix between the hypertrophied chondrocytes becomes impregnated with calcium salts (zone of calcification). Osteoblasts deposit bone matrix (pink) onto the calcified cartilage matrix (lavender) in the zone of ossification. Spongy bone, epiphysis Zone of reserve cartilage Zone of multiplication Zone of hypertrophy Zone of calcification Zone of ossification Bone matrix Osteoblast Zone of reserve cartilage Zone of multiplication Zone of hypertrophy Zone of calcification Epiphyseal disc Bone matrix Calcified cartilage matrix Calcified cartilage matrix Osteocyte Spongy bone, diaphysis Spongy bone, epiphysis Zone of reserve cartilage Zone of multiplication Zone of hypertrophy Zone of calcification Zone of ossification Marrow cavity </entry>
<entry linktype="AI" linkname="EUR-005-014" title="Figure 5.14: Endochondral Ossification, Phalanx, l.s., Decalcified, Dog">Endochondral Ossification, Phalanx, l.s., Decalcified, Dog. The zones of calcification and ossification are distinct in this preparation. Calcified cartilage matrix stains an intense purple, while bone matrix is strongly eosinophilic. Zone of ossification Osteocyte Osteoblast Bone matrix Calcified cartilage matrix Zone of ossification Bone marrow Zone of multiplication Zone of hypertrophy Zone of calcification Osteoblast Bone marrow </entry>
<entry linktype="AI" linkname="EUR-005-015" title="Figure 5.15: Endochondral Ossification, Epiphysis of Radius, Decalcified, Dog">Endochondral Ossification, Epiphysis of Radius, Decalcified, Dog. Numerous spicules of bone (pink) with cores of calcified cartilage matrix (lavender) are depicted. Bone matrix Sinusoid Osteocyte Osteoclast Osteoblast Bone marrow Calcified cartilage matrix Bone matrix Osteocyte Osteoblast Calcified cartilage matrix Bone marrow </entry>
<entry linktype="AI" linkname="EUR-005-016" title="Figure 5.16: Compact Ground Bone, Femur, x.s., Cat (Unstained)">Compact Ground Bone, Femur, x.s., Cat (Unstained). A Haversian canal surrounded by concentric bony lamellae constitutes a Haversian system (osteon). Lacunae with canaliculi (weblike, fine, dark lines) are occupied by osteocytes and their processes, respectively, in living tissue. Volkmann's canals (perforating canals), inner circumferential lamellae, and parts of old Haversian systems, called interstitial systems, are present. Inner circumferential lamellae Interstitial system Lacuna Haversian canal (Central canal) Volkmann's canal (Perforating canal) Haversian canal (Central canal) Haversian canal (Central canal) </entry>
<entry linktype="AI" linkname="EUR-005-017" title="Figure 5.17: Compact Ground Long Bone, x.s., Cat (Unstained)">Compact Ground Long Bone, x.s., Cat (Unstained). Spider-web-like channels, canaliculi, can be seen radiating from the lacunae. Haversian canal (Central canal) Haversian canal (Central canal) Lacuna Canaliculi Canaliculi </entry>
<entry linktype="AI" linkname="EUR-005-018" title="Figure 5.18: Compact Bone, Humerus, x.s., Decalcified, Chicken">Compact Bone, Humerus, x.s., Decalcified, Chicken. In decalcified bone, hydroxyapatites have been removed, leaving the collagenous portion of the matrix. Blood vessels, osteocytes, and other tissue elements are also left intact. Compare the appearance of the compact bone in this decalcified preparation to the dried ground compact bone in Figure 5.16 . Volkmann's canal (Perforating canal) Osteocyte Haversian canal (Central canal) </entry>
<entry linktype="AI" linkname="EUR-005-019" title="Figure 5.19: Compact Bone, x.s., Jaw, Decalcified, Dog">Compact Bone, x.s., Jaw, Decalcified, Dog. Blood vessels and nerves are evident in this cross section of a Haversian canal (central canal), as is the communication of the Haversian canal with a Volkmann's canal (perforating canal). Artery Vein Haversian (central) canal Nerve Osteocyte Volkmann's (perforating) canal </entry>
<entry linktype="AI" linkname="EUR-005-020" title="Figure 5.20: Compact Bone, Rib, l.s., Decalcified, Cat">Compact Bone, Rib, l.s., Decalcified, Cat. Portions of Haversian canals are oriented parallel to the long axis of the bone. The collagenous fibers of a tendon extend into the bone as Sharpey's fibers. The large cells in the bone marrow are megakaryocytes. Tendon Sharpey's fibers Osteocyte Haversian (central) canal Megakaryocyte Endosteum </entry>
<entry linktype="AI" linkname="EUR-005-021" title="Figure 5.21: Compact Bone, Rib, l.s., Decalcified, Cat">Compact Bone, Rib, l.s., Decalcified, Cat. Flat cells of the endosteum line the marrow cavity. Marrow cavity Endosteum Osteocyte </entry>
<entry linktype="AI" linkname="EUR-005-022" title="Figure 5.22: Periosteum of Femur, l.s., Decalcified, Cat">Periosteum of Femur, l.s., Decalcified, Cat. The periosteum parallels the bone of the diaphysis. Marrow cavity Fibrous layer, periosteum Osteogenic layer, periosteum Periosteum </entry>
<entry linktype="AI" linkname="EUR-005-023" title="Figure 5.23: Periosteum of Femur, l.s., Decalcified, Cat">Periosteum of Femur, l.s., Decalcified, Cat. A magnified view of the periosteum seen in Figure 5.22. The osteogenic layer of the periosteum abuts the bone and is more cellular than the outer fibrous layer of the periosteum. Fibrous layer, periosteum Osteogenic layer, periosteum Osteocyte Osteocyte </entry>
<entry linktype="AI" linkname="EUR-005-024" title="Figure 5.24: fSharpey's Fibers, Phalanx, l.s., Decalcified, Fetus, Sheep (Mallory's)">Sharpey's Fibers, Phalanx, l.s., Decalcified, Fetus, Sheep (Mallory's). Collagenous fibers of a tendon become embedded within the bone matrix, where they are called Sharpey's fibers. Cartilage Sharpey's fibers Bone matrix Tendon </entry>
<entry linktype="AI" linkname="EUR-005-025" title="Figure 5.25: Sharpey's Fibers, Phalanx, l.s., Decalcified, Fetus, Sheep (Mallory's)">Sharpey's Fibers, Phalanx, l.s., Decalcified, Fetus, Sheep (Mallory's). Same as Figure 5.24, but magnification has been increased to show the relationship between the bone matrix and the collagenous fibers of the tendon. Cartilage Sharpey’s fibers Bone matrix </entry>
<entry linktype="AI" linkname="EUR-005-026" title="Figure 5.26: Distal Interphalangeal Joint, l.s., Fetus, Horse">Distal Interphalangeal Joint, l.s., Fetus, Horse. The mid-dorsal aspect of this developing synovial joint is shown. The joint capsule is comprised of a fibrous portion and a well-vascularized, synovial membrane. The latter lines the joint cavity, except for the articulating surfaces. Synovial folds project into the cavity. The outer, more fibrous portion of the capsule is continuous with the future periosteum of the phalanges and blends dorsally with the extensor tendon. The tendon is attached to the developing extensor process of P3. Note that the phalanges have not yet begun to ossify. After ossification, a layer of hyaline cartilage will persist on the articular surfaces. Extensor tendon Extensor tendon Fibrous capsule Synovial fold of synovial membrane Articulating surface, P2 Articulating surface, P3 Joint cavity </entry>
<entry linktype="AI" linkname="EUR-006-001" title="Figure 6.1: Blood Cells in Histologic Section, Artery, Cat">Blood Cells in Histologic Section, Artery, Cat. Biconcave, disc-shaped erythrocytes, leukocytes, and plasma (pale pink) are within the lumen of an artery. Leukocyte Endothelial cell, nucleus Leukocyte Erythrocyte Erythrocyte Plasma </entry>
<entry linktype="AI" linkname="EUR-006-002" title="Figure 6.2: Blood, Dog (Giemsa)">Blood, Dog (Giemsa). Monocyte. The cytoplasm of the monocyte is typically vacuolated. The nucleus is frequently oval or U-shaped. Central pallor of the erythrocytes in this preparation is evident. Monocyte Erythrocyte </entry>
<entry linktype="AI" linkname="EUR-006-003" title="Figure 6.3: Blood, Dog (Giemsa)">Blood, Dog (Giemsa). Lymphocyte and neutrophil. The cytoplasm of the small lymphocyte is very sparse and the nuclear chromatin is condensed. The mature neutrophil has a polymorphic nucleus. The pale cytoplasm, barely discernible, is characteristic of the neutrophil of the dog. Lymphocyte Erythrocyte Neutrophil Platelet </entry>
<entry linktype="AI" linkname="EUR-006-004" title="Figure 6.4: Blood, Dog (Giemsa)">Blood, Dog (Giemsa). Basophil and neutrophil. The basophil has a polymorphic nucleus and coarse dark, basophilic granules of various sizes. Stain precipitate Neutrophil Basophil </entry>
<entry linktype="AI" linkname="EUR-006-005" title="Figure 6.5: Blood, Dog (Giemsa)">Blood, Dog (Giemsa). Eosinophils. In the eosinophil of the dog, the granules vary in size and number. Vacuoles occur in the cytoplasm. The eosinophil on the right is partially smudged. Eosinophil Smudged eosinophil </entry>
<entry linktype="AI" linkname="EUR-006-006" title="Figure 6.6: Blood, Cat (Giemsa)">Blood, Cat (Giemsa). Eosinophil, neutrophil, lymphocyte, monocyte and platelets. In the cat, platelets may be elongated, or cigar-shaped, as in this preparation. Eosinophil Erythrocyte Lymphocyte Platelet Neutrophil Monocyte </entry>
<entry linktype="AI" linkname="EUR-006-007" title="Figure 6.7: Blood, Cat (Giemsa)">Blood, Cat (Giemsa). Two monocytes. Erythrocytes are stacked in rouleaux. Monocyte Erythrocyte Rouleau Rouleau Monocyte </entry>
<entry linktype="AI" linkname="EUR-006-008" title="Figure 6.8: Buffy Coat, Cat (Giemsa)">Buffy Coat, Cat (Giemsa). One eosinophil, neutrophil, basophil, and platelets. A buffy coat is the layer above the packed erythrocytes of a centrifuged blood sample that contains mainly leukocytes and platelets. Eosinophils of the cat have pink, rod-shaped granules. The cytoplasm of the basophil contains numerous small, round, lavender granules that are tightly packed and may be difficult to resolve. Distinct red granules are scattered among the lavender granules. The nucleus of the neutrophil in the cat is often coiled, and the cytoplasm is slightly blue-gray with very fine granules that are difficult to see. Platelets vary greatly in size in the cat. Eosinophil Erythrocyte Smudged cell Platelet Basophil Smudged cell Neutrophil </entry>
<entry linktype="AI" linkname="EUR-006-009" title="Figure 6.9: Blood, Cat (Giemsa)">Blood, Cat (Giemsa). A basophil and platelets. The nuclei of basophils are remarkably long in the cat. Platelet Basophil </entry>
<entry linktype="AI" linkname="EUR-006-010" title="Figure 6.10: Blood, Cat (Giemsa)">Blood, Cat (Giemsa). An eosinophil, a neutrophil, and platelets. Eosinophil Neutrophil Platelet </entry>
<entry linktype="AI" linkname="EUR-006-011" title="Figure 6.11: Buffy Coat, Cat (Giemsa)">Buffy Coat, Cat (Giemsa). Three eosinophils, one neutrophil, one basophil, three lymphocytes, and platelets. Neutrophil Lymphocyte Eosinophil Lymphocyte Platelet Erythrocyte Smudged cell Eosinophil Eosinophil Basophil Lymphocyte </entry>
<entry linktype="AI" linkname="EUR-006-012" title="Figure 6.12: Blood, Horse (Giemsa)">Blood, Horse (Giemsa). Eosinophil, monocyte, two neutrophils, and lymphocyte. In the neutrophil of the horse, the nucleus often appears very jagged. Eosinophil Neutrophil Erythrocytel Neutrophil Monocyte Lymphocyte </entry>
<entry linktype="AI" linkname="EUR-006-013" title="Figure 6.13: Blood, Horse (Giemsa)">Blood, Horse (Giemsa). Eosinophil. The eosinophil of the horse has characteristic, large, round granules. The surface of the cell looks bumpy where granules are pressed against the plasma membrane, giving the cell a raspberry-like appearance. Eosinophil Erythrocytel </entry>
<entry linktype="AI" linkname="EUR-006-014" title="Figure 6.14: Blood, Horse (Giemsa)">Blood, Horse (Giemsa). Eosinophil. Note the rouleaux (stacks of erythrocytes), which are common in the horse. Eosinophil </entry>
<entry linktype="AI" linkname="EUR-006-016" title="Figure 6.16: Blood, Horse (Giemsa)">Blood, Horse (Giemsa). Monocyte. A typical monocyte with pale cytoplasm and linearly arranged chromatin. Monocyte </entry>
<entry linktype="AI" linkname="EUR-006-017" title="Figure 6.17: Blood, Horse (Giemsa)">Blood, Horse (Giemsa). Three neutrophils and one monocyte. Monocyte Neutrophil Neutrophil Neutrophil </entry>
<entry linktype="AI" linkname="EUR-006-018" title="Figure 6.18: Buffy Coat, Horse (Giemsa)">Buffy Coat, Horse (Giemsa). Basophil and neutrophil. Granules of the basophil are purple and vary in size and shape. The nucleus of the neutrophil has a characteristic, jagged contour. Platelet Erythrocytel Neutrophil Basophil </entry>
<entry linktype="AI" linkname="EUR-006-019" title="Figure 6.19: Blood, Pig (Giemsa)">Blood, Pig (Giemsa). Two lymphocytes and a monocyte. Lymphocyte Erythrocyte Platelet Lymphocyte Monocyte </entry>
<entry linktype="AI" linkname="EUR-006-020" title="Figure 6.20: Blood, Pig (Giemsa)">Blood, Pig (Giemsa). Two lymphocytes, one neutrophil, and two eosinophils. The eosinophil of the pig contains numerous pink, round granules that fill the cytoplasm. The nucleus of the eosinophil is not highly segmented. It varies from oval to deeply indented. Note the coiled appearance of the nucleus of the neutrophil, a common feature in pigs and cats. Crenated erythrocytes are commonly seen in blood smears from the pig. Rouleaux also are evident in this field. Lymphocyte Neutrophil Erythrocyte, crenated Platelet Lymphocyte Eosinophil Rouleau Eosinophil </entry>
<entry linktype="AI" linkname="EUR-006-021" title="Figure 6.21: Blood, Pig (Giemsa)">Blood, Pig (Giemsa). Two lymphocytes and an eosinophil. In pigs, the nucleus of eosinophils varies from oval, as shown in this image, to deeply indented. Eosinophil Lymphocyte Erythrocyte, crenated Platelet Lymphocyte </entry>
<entry linktype="AI" linkname="EUR-006-022" title="Figure 6.22: Blood, Pig (Giemsa)">Blood, Pig (Giemsa). Eosinophil, basophil, lymphocyte, and a smudged cell. The granules of the basophil of the pig are dumbbell or coccoid in shape. Some of the granules have been squeezed from the basophil in this preparation. Lymphocyte Smudged cell Basophil granules Basophil Eosinophil </entry>
<entry linktype="AI" linkname="EUR-006-023" title="Figure 6.23: Blood, Pig (Giemsa)">Blood, Pig (Giemsa). Basophil and two lymphocytes. Lymphocyte Basophil Platelet Lymphocyte </entry>
<entry linktype="AI" linkname="EUR-006-024" title="Figure 6.24: Blood, Cow (Giemsa)">Blood, Cow (Giemsa). Lymphocyte, monocyte, and neutrophil. The ends of the elongated nucleus of the monocyte are partly overlapped, making it appear ringlike at first glance. Lymphocyte Erythrocyte Monocyte Neutrophil </entry>
<entry linktype="AI" linkname="EUR-006-025" title="Figure 6.25: Blood, Cow (Giemsa)">Blood, Cow (Giemsa). Eosinophil. The red granules of the eosinophil are small, round, and intensely stained in the cow. The nucleus may be lobed, but is usually C-shaped. Eosinophil </entry>
<entry linktype="AI" linkname="EUR-006-026" title="Figure 6.26: Blood, Cow (Giemsa)">Blood, Cow (Giemsa). Eosinophil and a lymphocyte. Eosinophil Lymphocyte </entry>
<entry linktype="AI" linkname="EUR-006-028" title="Figure 6.28: Blood, Cow (Giemsa)">Blood, Cow (Giemsa). Lymphocyte. The large lymphocyte of the cow often shows a deeply indented nucleus. The cytoplasm is granular and vacuolated. Lymphocyte </entry>
<entry linktype="AI" linkname="EUR-006-029" title="Figure 6.29: Blood, Cow (Giemsa)">Blood, Cow (Giemsa). An eosinophil and two lymphocytes. Lymphocyte Eosinophil Lymphocyte </entry>
<entry linktype="AI" linkname="EUR-006-031" title="Figure 6.31: Blood, Sheep (Giemsa)">Blood, Sheep (Giemsa). Binucleate lymphocyte. Some of the lymphocytes of ruminants have two nuclei. Lymphocyte, binucleate Platelet </entry>
<entry linktype="AI" linkname="EUR-006-032" title="Figure 6.32: Blood, Sheep (Giemsa)">Blood, Sheep (Giemsa). Monocyte. The nucleus of the monocytes of ruminants may be oval or indented, or have a three-pronged configuration. The cytoplasm is gray-blue and vacuolated and may contain granules. Monocyte Platelet </entry>
<entry linktype="AI" linkname="EUR-006-033" title="Figure 6.33: Blood, Sheep (Giemsa)">Blood, Sheep (Giemsa). Monocyte. This monocyte has a three-pronged nucleus. Our observations have revealed that some monocytes with similar nuclei also occur in cows and goats. Monocyte </entry>
<entry linktype="AI" linkname="EUR-006-034" title="Figure 6.34: Blood, Sheep (Giemsa)">Blood, Sheep (Giemsa). Lymphocyte and neutrophil. The cytoplasm of the neutrophil of sheep and goats contains numerous small and a few large, pink granules. A perinuclear halo is commonly seen around the periphery of the nucleus of lymphocytes. Erythrocyte Neutrophil Lymphocyte </entry>
<entry linktype="AI" linkname="EUR-006-036" title="Figure 6.36: Blood, Sheep (Giemsa)">Blood, Sheep (Giemsa). Eosinophil. The eosinophil of the sheep contains pink, densely packed, oval granules that are uniform in size. Eosinophil </entry>
<entry linktype="AI" linkname="EUR-006-037" title="Figure 6.37: Blood, Goat (Giemsa)">Blood, Goat (Giemsa). Two lymphocytes and a neutrophil. The chromatin of the lymphocytes is in the form of closely apposed clumps. Fine granules are present in the cytoplasm of the neutrophil but are difficult to see. Lymphocyte Platelet Neutrophil Lymphocyte Platelet </entry>
<entry linktype="AI" linkname="EUR-006-038" title="Figure 6.38: Buffy Coat, Goat (Giemsa)">Buffy Coat, Goat (Giemsa). Lymphocyte and neutrophil. Lymphocyte Neutrophil</entry>
<entry linktype="AI" linkname="EUR-006-039" title="Figure 6.39: Buffy Coat, Goat (Giemsa)">Buffy Coat, Goat (Giemsa). Eosinophil. The small, round, acidophilic granules of the eosinophil of the goat almost fill the cytoplasm. Platelet Eosinophil Erythrocyte </entry>
<entry linktype="AI" linkname="EUR-006-040" title="Figure 6.40: Buffy Coat, Goat (Giemsa)">Buffy Coat, Goat (Giemsa). Two lymphocytes. Some lymphocytes of the cow, sheep, and goat are binucleate, as is one of the lymphocytes in this image. Lymphocyte Platelet Lymphocyte, binucleate </entry>
<entry linktype="AI" linkname="EUR-006-041" title="Figure 6.41: Buffy Coat, Goat (Giemsa)">Buffy Coat, Goat (Giemsa). Monocyte. The cytoplasm of the monocyte is blue and contains vacuoles that are often seen in clusters. Monocyte </entry>
<entry linktype="AI" linkname="EUR-006-042" title="Figure 6.42: Buffy Coat, Goat (Giemsa)">Buffy Coat, Goat (Giemsa). Monocyte and lymphocytes. The nucleus of this monocyte appears amoeboid or three-pronged, as occurs in ruminants. Lymphocyte Lymphocyte, binucleate Erythrocyte Monocyte Lymphocyte Lymphocyte Platelet </entry>
<entry linktype="AI" linkname="EUR-006-043" title="Figure 6.43: Blood Cells in Histologic Section, Chicken">Blood Cells in Histologic Section, Chicken. Elongated, nucleated red blood cells and a few granulocytes are shown in the lumen of a blood vessel. Granulocyte Erythrocyte </entry>
<entry linktype="AI" linkname="EUR-006-045" title="Figure 6.45: Blood, Chicken (Wright-Giemsa)">Blood, Chicken (Wright-Giemsa). Erythrocytes and thrombocytes. An oval, coarsely granular nucleus and a vacuolated cytoplasm with one or more magenta granules characterize the thrombocyte. Thrombocyte Vacuole Erythrocyte Thrombocyte </entry>
<entry linktype="AI" linkname="EUR-006-046" title="Figure 6.46: Blood, Chicken (Wright-Giemsa)">Blood, Chicken (Wright-Giemsa). Eosinophil, two lymphocytes, and a heterophil. The heterophil has numerous rod-shaped granules. Some of these may show a ruby-red, spherical granule at the center. The nuclear chromatin is coarse and densely packed. In contrast, the eosinophil has fewer round, pink granules in a pale blue cytoplasm. The nuclear chromatin is blocklike; the blocks are distinctly separated from each other. Lymphocyte Erythrocyte Lymphocyte Heterophil Eosinophil </entry>
<entry linktype="AI" linkname="EUR-006-047" title="Figure 6.47: Blood, Chicken (Wright-Giemsa)">Blood, Chicken (Wright-Giemsa). Basophil, heterophil, monocyte, and immature erythrocyte. The basophil is characterized by large numbers of medium-size basophilic granules. Unlike other granulocytes, the nucleus of this cell is usually not lobed. The cytoplasm of the immature erythrocyte is more basophilic and the nucleus is less condensed than in a mature erythrocyte. Smudged heterophil Monocyte Immature erythrocyte Basophil </entry>
<entry linktype="AI" linkname="EUR-006-048" title="Figure 6.48: Blood, Chicken (Wright-Giemsa)">Blood, Chicken (Wright-Giemsa). Eosinophil and smudged heterophil. The rod-shaped granules of the heterophil and the round granules of the eosinophil are clearly visible. Eosinophil Smudged heterophil </entry>
<entry linktype="AI" linkname="EUR-006-049" title="Figure 6.49: Blood, Chicken (Wright-Giemsa)">Blood, Chicken (Wright-Giemsa). Monocyte and heterophil. Many of the rod-shaped granules of the heterophil have a ruby red, spherical granule at their center. This is a common characteristic of the heterophil. The monocyte has a pale, basophilic, and vacuolated cytoplasm. Heterophil Monocyte </entry>
<entry linktype="AI" linkname="EUR-007-001" title="Figure 7.1: Megakaryocyte, Bone Marrow, Cat (Giemsa)">Megakaryocyte, Bone Marrow, Cat (Giemsa). The megakaryocyte is a large cell with a polymorphic nucleus and grainy cytoplasm. Blood platelets are derived from fragments of the cytoplasm. Forces generated during the formation of the smear appear to have separated a segment of the nucleus. Erythroid cell, late Megakaryocyte Granulocytic cell, early Granulocytic cell, early </entry>
<entry linktype="AI" linkname="EUR-007-002" title="Figure 7.2: Osteoclast, Bone Marrow, Cat (Giemsa)">Osteoclast, Bone Marrow, Cat (Giemsa). The osteoclast is a large, multinucleate cell formed from fused macrophages. Azurophilic bone debris can be seen in the cytoplasm of this specimen. Erythroid cell, late Erythrocyte Granulocytic cell, early Granulocytic cell, early Azurophilic debris Azurophilic debris Osteoclast </entry>
<entry linktype="AI" linkname="EUR-007-003" title="Figure 7.3: Osteoblasts, Bone Marrow, Cat (Giemsa)">Osteoblasts, Bone Marrow, Cat (Giemsa). Osteoblasts are characterized by the presence of an eccentric nucleus and basophilic cytoplasm. A perinuclear clear zone, representing the site of the Golgi apparatus, may be visible. In smears these cells often occur in clusters. Eosinophilic myelocyte Basophilic erythroblast Neutrophilic band cell Erythroid cell, late Osteoblast </entry>
<entry linktype="AI" linkname="EUR-007-004" title="Figure 7.4: Bone Marrow, Cat (Giemsa)">Bone Marrow, Cat (Giemsa). A variety of different cells of the bone marrow can be identified at this magnification. Basophilic erythroblast Eosinophilic band cell Neutrophilic band cell Mitotic figure Plasma cell Orthochromatophilic erythroblast Erythrocyte </entry>
<entry linktype="AI" linkname="EUR-007-005" title="Figure 7.5: Bone Marrow, Cat (Giemsa)">Bone Marrow, Cat (Giemsa). Basophilic and eosinophilic myelocytes are represented in this field. Basophilic myelocyte Eosinophilic myelocyte Smudged cell, nucleus Erythrocyte </entry>
<entry linktype="AI" linkname="EUR-007-006" title="Figure 7.6: Bone Marrow, Cat (Wright-Giemsa)">Bone Marrow, Cat (Wright-Giemsa). A basophilic myelocyte, segmented eosinophil, and polychromatophilic erythroblast are evident. Polychromatophilic erythroblast Eosinophil Basophilic myelocyte Reticulocyte </entry>
<entry linktype="AI" linkname="EUR-007-007" title="Figure 7.7: Bone Marrow, Cat (Wright-Giemsa)">Bone Marrow, Cat (Wright-Giemsa). Various myeloid developmental stages are shown in this field. Basophilic band cell Neutrophilic band cell Neutrophilic metamyelocyte Neutrophil </entry>
<entry linktype="AI" linkname="EUR-007-008" title="Figure 7.8: Bone Marrow, Cat (Wright-Giemsa)">Bone Marrow, Cat (Wright-Giemsa). Various erythroid developmental stages are shown in this field. Polychromatophilic erythroblast Basophilic erythroblast Orthochromatophilic erythroblast </entry>
<entry linktype="AI" linkname="EUR-007-009" title="Figure 7.9: Bone Marrow, Cat (Wright-Giemsa)">Bone Marrow, Cat (Wright-Giemsa). The largest cell seen in this field is a promyelocyte. Note the presence of numerous magenta, azurophilic granules in its cytoplasm. Neutrophilic metamyelocyte, late Orthochromatophilic erythroblast Neutrophilic band cell Promyelocyte </entry>
<entry linktype="AI" linkname="EUR-007-010" title="Figure 7.10: Bone Marrow, Plastic Section, Chicken (Giemsa)">Bone Marrow, Plastic Section, Chicken (Giemsa). Intravascular developmental stages of erythrocytes are shown. In the extravascular compartment, heterophils and eosinophils can be distinguished. Eosinophil Endothelial cell, nucleus Erythrocyte, early Eosinophil Erythrocyte, early Erythrocyte, mature Heterophil </entry>
<entry linktype="AI" linkname="EUR-008-001" title="Figure 8.1: Smooth Muscle Tissue, Ileum, x.s., Cat">Smooth Muscle Tissue, Ileum, x.s., Cat. The muscularis externa of the small intestine consists of two layers of smooth muscle tissue arranged at right angles to one another, namely the inner circular layer and outer longitudinal layer. An area similar to the one outlined within a rectangle in this image is shown in detail in Figure 8.2. Ileum, lumen Villus Separation artifact Serosa Area shown in Figure 8.2 Muscularis externa, inner circular layer Muscularis externa, outer longitudinal layer </entry>
<entry linktype="AI" linkname="EUR-008-002" title="Figure 8.2: Smooth Muscle Tissue, Ileum, x.s., Cat">Smooth Muscle Tissue, Ileum, x.s., Cat. In this cross section, the smooth muscle cells of the inner circular layer of the muscularis externa, which are oriented circularly relative to the lumen of the organ, have been cut longitudinally. The muscle cells of the outer longitudinal layer, which parallel the long axis of the organ, have been cut transversely. This image includes the simple squamous epithelium, the mesothelium, of the serosa that covers the ileum. Smooth muscle cell, nucleus, l.s. Smooth muscle cell, sarcoplasm Smooth muscle cell, sarcoplasm Smooth muscle cell, nucleus, l.s. Smooth muscle cell, nucleus, x.s. Smooth muscle cell, nucleus, x.s. Simple squamous cell, nucleus Simple squamous cell, nucleus Smooth muscle cell, sarcoplasm Smooth muscle cell, sarcoplasm Smooth muscle cell, nucleus, l.s. Smooth muscle cell, nucleus, x.s. Smooth muscle cell, sarcoplasm Smooth muscle cell, sarcoplasm Smooth muscle cell, sarcoplasm Smooth muscle cell, nucleus, x.s. </entry>
<entry linktype="AI" linkname="EUR-008-003" title="Figure 8.3: Smooth Muscle Tissue, Muscularis Externa, Jejunum, x.s., Sheep">Smooth Muscle Tissue, Muscularis Externa, Jejunum, x.s., Sheep. This is a magnified view of the layers of the muscularis externa showing smooth muscle tissue in x.s. and l.s. Smooth muscle cells each have a single, elongated nucleus sometimes referred to as cigar-shaped. This shape is apparent in cells that have been sectioned longitudinally. In a group of smooth muscle cells, the cells are oriented in the same direction and fitted closely together with tapered ends of some cells positioned between mid-portions of other cells. Thus, their nuclei appear staggered in smooth muscle tissue sectioned longitudinally and, because of the snug arrangement of the cells, their boundaries are often not discernable. The appearance of smooth muscle cells in cross section varies, depending on where they were transected along their length. If a cell was sliced through its mid region, its basophilic nucleus is visible and appears round. If the cell was cut closer to a tapered end, only eosinophilic cytoplasm, not the nucleus, is present and the cell appears smaller in diameter. Smooth muscle cell, sarcoplasm Smooth muscle cell, nucleus, l.s. Smooth muscle cell, nucleus, x.s. Smooth muscle cell, sarcoplasm Smooth muscle cell, sarcoplasm Smooth muscle cell, sarcoplasm Smooth muscle cell, nucleus, x.s. </entry>
<entry linktype="AI" linkname="EUR-008-004" title="Figure 8.4: Smooth Muscle Tissue, Coronary Artery, x.s., Pig">Smooth Muscle Tissue, Coronary Artery, x.s., Pig. The smooth muscle tissue in the tunica media of this blood vessel is contracted, as evidenced by the twisted appearance of the nuclei of the smooth muscle cells. Due to the arrangement of myofilaments and the presence of additional elements in the sarcoplasm of smooth muscle cells, the cells coil and bunch up as they shorten. Artery, lumen Smooth muscle cell, nucleus, l.s. Smooth muscle cell, nucleus, l.s. Smooth muscle cell, sarcoplasm Connective tissue Nerve fascicle, unmyelinated </entry>
<entry linktype="AI" linkname="EUR-008-005" title="Figure 8.5: Smooth Muscle Tissue, Urinary Bladder, Pig">Smooth Muscle Tissue, Urinary Bladder, Pig. The spindle-shape of individual smooth muscle cells in longitudinal section and their variable appearance in cross section are particularly evident here. An arteriole, with smooth muscle cells in its wall, is present. Smooth muscle cell, sarcoplasm Smooth muscle cell, nucleus, l.s. Smooth muscle cell, nucleus, l.s. 7 Arteriole, lumen Collagenous fiber Venule Smooth muscle cell, sarcoplasm Smooth muscle cell, sarcoplasm Smooth muscle cell, nucleus, x.s. Fibroblast, nucleus </entry>
<entry linktype="AI" linkname="EUR-008-006" title="Figure 8.6: Smooth Muscle Tissue and Dense Irregular Connective Tissue, Duodenum, Cat">Smooth Muscle Tissue and Dense Irregular Connective Tissue, Duodenum, Cat. Layers of smooth muscle tissue, cut longitudinally and transversely, of the muscularis mucosa can be distinguished from the dense irregular connective tissue of the submucosa. The collagenous fibers of the connective tissue are shinier and a brighter pink color than the cytoplasm of the muscle cells. The elongated, pale nuclei of the smooth muscle cells in longitudinal section are aligned in the same direction. The dark nuclei of fibroblasts of the connective tissue are more irregularly arranged. Simple columnar epithelium Crypt of Lieberk├╝hn (intestinal gland) Fibroblast, nucleus Smooth muscle cell, nucleus, l.s. Smooth muscle cell, nucleus, x.s. Collagenous fiber Smooth muscle cell, sarcoplasm Muscularis mucosae Dense irregular connective tissue Smooth muscle cell, nucleus, x.s. Collagenous fiber Smooth muscle cell, sarcoplasm Smooth muscle cell, nucleus, l.s. Fibroblast, nucleus </entry>
<entry linktype="AI" linkname="EUR-008-007" title="Figure 8.7: Skeletal Muscle Tissue, x.s. and l.s., Tongue, Cat">Skeletal Muscle Tissue, x.s. and l.s., Tongue, Cat. The tongue is highly muscular, with bundles of skeletal muscle cells oriented perpendicular to one another. For this reason, the tongue serves as a useful specimen to observe skeletal muscle tissue in both longitudinal and cross sections. Figure 8.8 is a magnified view of skeletal muscle tissue of a tongue. Connective tissue Stratified squamous epithelium Skeletal muscle cell, l.s. Skeletal muscle cell, x.s. Skeletal muscle cell, l.s. Skeletal muscle cell, l.s. Perimysium Skeletal muscle cell, x.s. Skeletal muscle cell, x.s. Skeletal muscle cell, x.s. </entry>
<entry linktype="AI" linkname="EUR-008-008" title="Figure 8.8: Skeletal Muscle Tissue, x.s. and l.s., Tongue, Horse">Skeletal Muscle Tissue, x.s. and l.s., Tongue, Horse. Skeletal muscle cells are large and long and possess numerous, peripheral nuclei. Some of the nuclei that are near the skeletal muscle cells belong to cells of the endomysium and perimysium. In skeletal muscle cells cut longitudinally, cross-striations are evident as thin light and dark stripes perpendicular to the long axis of the cell. When cut transversely, the cells appear round to polygonal, and myofibrils are visible as dots packed in the cytoplasm. If a skeletal muscle cell is sectioned near its surface, its nuclei appear to be more centrally located. Skeletal muscle cell, nucleus, superficial cut Skeletal muscle cell, nucleus, superficial cut Separation artifact Skeletal muscle cell, oblique cut Endomysium Skeletal muscle cell, nucleus Skeletal muscle cell, l.s. Perimysium Skeletal muscle cell, nucleus Capillary, x.s. Myofibrils, x.s., in sarcoplasm Capillary, x.s. Skeletal muscle cell, x.s. Skeletal muscle cell, x.s. Skeletal muscle cell, x.s. </entry>
<entry linktype="AI" linkname="EUR-008-009" title="Figure 8.9: Skeletal Muscle Tissue, l.s., Lip, Dog (Masson's)">Skeletal Muscle Tissue, l.s., Lip, Dog (Masson's). Individual myofibrils that have frayed apart at the cut ends of these two skeletal muscle cells in longitudinal section are distinct. The light and dark bands of the myofibrils line up with those of other myofibrils within each cell, so that each entire cell appears cross-striated. H band A band I band Z line H band Muscle cell, l.s. Muscle cell, l.s. Endomysium A band I band Z line Myofibrils </entry>
<entry linktype="AI" linkname="EUR-008-010" title="Figure 8.10: Skeletal Muscle Tissue, x.s., Tongue, Horse">Skeletal Muscle Tissue, x.s., Tongue, Horse. In cross section, the skeletal muscle cells are round to polygonal. Myofibrils are packed in the cytoplasm and peripheral nuclei are evident. Separation artifact between skeletal muscle cells makes the individual cells more distinct and reveals the capillaries and loose connective tissue of the endomysium. Capillary, x.s. Skeletal muscle cell, nucleus Separation artifact Endomysium Myofibrils, x.s., in sarcoplasm Capillary, x.s. Skeletal muscle cell, nucleus Skeletal muscle cell, x.s. </entry>
<entry linktype="AI" linkname="EUR-008-011" title="Figure 8.11: Skeletal Muscle Tissue, x.s., Tongue, Horse">Skeletal Muscle Tissue, x.s., Tongue, Horse. Myofibrils are eosinophilic rod-like structures that extend the length of the muscle cell and are formed by myofilaments. In skeletal muscle cells that are cut in cross section, their myofibrils are also cut in cross section and appear as numerous dot-like structures packed in the sarcoplasm. They are especially evident in this preparation. Skeletal muscle cell, nucleus Capillary, x.s. Skeletal muscle cell, x.s. Myofibrils, x.s., in sarcoplasm Capillary, x.s. Skeletal muscle cell, nucleus </entry>
<entry linktype="AI" linkname="EUR-008-012" title="Figure 8.12: keletal Muscle and Tendon, Oblique Cut, Tongue, Horse">Skeletal Muscle and Tendon, Oblique Cut, Tongue, Horse. The collagenous fibers of the dense regular connective tissue of a tendon can be seen associated with skeletal muscle cells. Dense regular connective tissue Skeletal muscle cell, x.s. Skeletal muscle cell, oblique section Skeletal muscle cell, oblique section Adipose tissue Separation artifact </entry>
<entry linktype="AI" linkname="EUR-008-013" title="Figure 8.13: Skeletal and Smooth Muscle Tissue, Sheep (Masson's)">Skeletal and Smooth Muscle Tissue, Sheep (Masson's). The spindle shape of the individual smooth muscle cells cut longitudinally is evident. Cross-striations of portions of skeletal muscle cells in longitudinal section are also visible. With the connective tissue stain used to color this preparation, collagenous fibers are blue/green while the cytoplasm of the muscle cells is magenta (purplish red). Collagenous fiber Smooth muscle cell, sarcoplasm Smooth muscle cell, nucleus Smooth muscle cell, sarcoplasm Smooth muscle cell, nucleus Collagenous fiber Skeletal muscle cell, nucleus Skeletal muscle cell, nucleus Skeletal muscle cell, l.s. </entry>
<entry linktype="AI" linkname="EUR-008-014" title="Figure 8.14: Cardiac Muscle Tissue, l.s., Heart, Cat">Cardiac Muscle Tissue, l.s., Heart, Cat. Branching (bifurcation) of the cardiac muscle cells is visible and endomysium is discernible where separation artifact has occurred. Intercalated disk Intercalated disk Cardiac muscle cell, nucleus, l.s. Endomysium Separation artifact Endomysium Bifurcation Cardiac muscle cell, nucleus, l.s. </entry>
<entry linktype="AI" linkname="EUR-008-015" title="Figure 8.15: Cardiac Muscle Tissue, l.s., Heart, Cat">Cardiac Muscle Tissue, l.s., Heart, Cat. Branching and cross-striations are apparent in this preparation. Intercalated discs appear as dark, somewhat irregular lines perpendicular to the long axis of the cells and are thicker than cross-striations. (Intercalated discs are not always apparent in H and E preparations.) Nuclei of cardiac muscle cells are centrally located. Nuclei of cells of the endomysium between cardiac muscle cells are also visible. Intercalated disk Cardiac muscle cell, nucleus, l.s. Intercalated disk Cardiac muscle cell, nucleus, l.s. Separation artifact Fibroblast, nucleus </entry>
<entry linktype="AI" linkname="EUR-008-016" title="Figure 8.16: Cardiac Muscle Tissue, x.s.,Heart, Pig">Cardiac Muscle Tissue, x.s., Heart, Pig. Separation artifact exposes the boundaries of the cardiac muscle cells cut in cross section and the location of the endomysium between them. In many cardiac muscle cells, their centrally located nucleus is visible; in others it was not included in the plane of the section. Cross sections vary in shape and diameter, depending on the plane of section through the branching cells. Capillary, x.s Separation artifact Cardiac muscle cell, x.s. Cardiac muscle cell, x.s. Endomysium Capillary, x.s Cardiac muscle cell, nucleus, x.s. Cardiac muscle cell, nucleus, x.s. Cardiac muscle cell, x.s. Fibroblast, nucleus Cardiac muscle cell, x.s. </entry>
<entry linktype="AI" linkname="EUR-008-017" title="Figure 8.17: Cardiac Muscle Tissue, x.s., Heart, Pig">Cardiac Muscle Tissue, x.s., Heart, Pig. In cardiac muscle cells, the myofibrils separate around the centrally located nucleus, forming a perinuclear halo of 'clear' cytoplasm free of myofibrils. Capillary, x.s Cardiac muscle cell, nucleus, x.s. Myofibrils, x.s., in sarcoplasm Cardiac muscle cell, x.s. Cardiac muscle cell, x.s. Cardiac muscle cell, nucleus, x.s. Endomysium Capillary, x.s </entry>
<entry linktype="AI" linkname="EUR-009-001" title="Figure 9.1: Cerebellum, Sheep">Cerebellum, Sheep. The molecular and granular layers of the gray matter and Purkinje cells are shown. The white matter lies deep to the gray matter. Pia mater Pia mater Molecular layer Purkinje cell Granular layer White matter Subarachnoid space </entry>
<entry linktype="AI" linkname="EUR-009-002" title="Figure 9.2: Cerebellum, Sheep">Cerebellum, Sheep. Portions of the dendritic tree of the multipolar Purkinje cells are visible. Dendrite Molecular layer Purkinje cell </entry>
<entry linktype="AI" linkname="EUR-009-003" title="Figure 9.3: Cerebral Cortex, Dog">Cerebral Cortex, Dog. Outer portions of cerebral cortex with numerous blood vessels. Blood vessel Pyramidal cell Pyramidal cell layer Pyramidal cell Outer granular layer Molecular layer Pia mater </entry>
<entry linktype="AI" linkname="EUR-009-004" title="Figure 9.4: Cerebral Cortex, Pyramidal Cells, Dog">Cerebral Cortex, Pyramidal Cells, Dog. Magnified view of cells of the pyramidal layer. Pyramidal cell Pyramidal cell </entry>
<entry linktype="AI" linkname="EUR-009-005" title="Figure 9.5: Dura Mater, Goat">Dura Mater, Goat. The dura remains attached to the skull when the latter is separated from the brain. It is a dense fibroelastic layer lined by a mesothelium. The dura merges with the periosteum of the skull. Bone, skulll Periosteum Dura mater Mesothelium </entry>
<entry linktype="AI" linkname="EUR-009-006" title="Figure 9.6: Meninges, Cerebellum, Sheep (Mallory's)">Meninges, Cerebellum, Sheep (Mallory's). The arachnoid mater, subarachnoid space, and pia mater are shown. The subarachnoid space is filled with cerebrospinal fluid, which is stained purple. Wisps of collagenous fibers (blue) can be seen within the subarachnoid space. These connect the arachnoid layer with the pia. Arachnoid mater Collagenous fiber Cerebrospinal fluid Collagenous fiber Pia mater Molecular layer Small artery Arachnoid mater Pia mater </entry>
<entry linktype="AI" linkname="EUR-009-007" title="Figure 9.7: Cerebellum, Dog">Cerebellum, Dog. Portion of a sulcus containing a venule. The perivascular space surrounding the vessel is continuous with the subarachnoid space and separates the vessel from the pia mater on either side. Purkinje cell Molecular layer Capillary Pia mater Perivascular space Venule Pia mater </entry>
<entry linktype="AI" linkname="EUR-009-008" title="Figure 9.8: Choroid Plexus, Cat (Cresyl Violet)">Choroid Plexus, Cat (Cresyl Violet). Portion of the fourth ventrical with choroid plexus in the roof of the medulla. Cerebellum, vermis Fourth ventricle Choroid plexus Medulla </entry>
<entry linktype="AI" linkname="EUR-009-009" title="Figure 9.9: Choroid Plexus, Dog">Choroid Plexus, Dog. The simple cuboidal epithelium and large, thin-walled capillaries are major constituents of the villi of the choroid plexus. Capillary Fourth ventricle Villus, x.s. Epithelium Epithelium Capillary Fourth ventricle </entry>
<entry linktype="AI" linkname="EUR-009-010" title="Figure 9.10: Brain Sand, Hypothalamus, Dog">Brain Sand, Hypothalamus, Dog. Calcified, granular material called brain sand can be found dispersed through various parts of the brain, including the hypothalamus, cerebellum, and pineal gland. Brain sand Brain sand </entry>
<entry linktype="AI" linkname="EUR-009-011" title="Figure 9.11: Fibrous Astrocytes, Medulla, Cat (Golgi)">Fibrous Astrocytes, Medulla, Cat (Golgi). These neuroglia cells have long processes that show little or no branching. Astrocyte, process Astrocyte, process Astrocyte, cell body Neuron </entry>
<entry linktype="AI" linkname="EUR-009-012" title="Figure 9.12: Spinal Cord, Cervical, x.s., Sheep">Spinal Cord, Cervical, x.s., Sheep The area outlined by the rectangle is shown in Figure 9.13. Central canal Gray matter, ventral horn White matter Gray matter, ventral horn Area shown in Figure 9.13 </entry>
<entry linktype="AI" linkname="EUR-009-013" title="Figure 9.13: Spinal Cord, Cervical, x.s., Sheep (Masson's).">Spinal Cord, Cervical, x.s., Sheep (Masson's). The central canal, gray matter, and white matter are shown. The cell bodies of multipolar neurons reside in the gray matter. Central canal Multipolar neuron, cell body Gray matter, ventral horn Multipolar neuron, cell body White matter White matter Multipolar neuron, cell body Gray matter, ventral horn Multipolar neuron, cell body </entry>
<entry linktype="AI" linkname="EUR-009-014" title="Figure 9.14: Central Canal, Spinal Cord, x.s., Sheep">Central Canal, Spinal Cord, x.s., Sheep. Tall ependymal cells, some of which are ciliated, line the central canal. Gray matter Central canal Cilia Gray matter </entry>
<entry linktype="AI" linkname="EUR-009-015" title="Figure 9.15: Multipolar Neurons, Spinal Cord, Sheep">Multipolar Neurons, Spinal Cord, Sheep. The axon hillock of two neurons can be seen. Nissl granules are absent from the hillock region, but extend into the dendrites. Nissl granules Nucleus Axon hillock Axon hillock Dendrite Dendrite Nissl granules </entry>
<entry linktype="AI" linkname="EUR-009-016" title="Figure 9.16: Multipolar Neurons, Spinal Cord, Sheep">Multipolar Neurons, Spinal Cord, Cow. Two multipolar neurons are shown in this smear preparation. Note prominent nucleoli and Nissl granules. Nucleolus Nucleus Neuron cell body Dendrite Dendrite </entry>
<entry linktype="AI" linkname="EUR-009-017" title="Figure 9.17: Dorsal Root Ganglion, Dog (Luxol Fast Blue/Cresylecht Violet)">Dorsal Root Ganglion, Dog (Luxol Fast Blue/Cresylecht Violet). Portion of a dorsal root ganglion showing neurons and nerve fibers. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Neuron cell body Nerve fibers Neuron cell body Nerve fibers </entry>
<entry linktype="AI" linkname="EUR-009-018" title="Figure 9.18: Dorsal Root Ganglion, Dog (Luxol Fast Blue/Cresylecht Violet)">Dorsal Root Ganglion, Dog (Luxol Fast Blue/Cresylecht Violet). Flattened satellite cells envelop the round neuron cell bodies of the unipolar neurons. (Photograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Satellite cell Nissl granules Neuron cell body Nissl granules Nerve fiber Satellite cell </entry>
<entry linktype="AI" linkname="EUR-009-019" title="Figure 9.19: Parasympathetic Ganglion, Pulmonary Artery, Dog">Parasympathetic Ganglion, Pulmonary Artery, Dog. A ganglion and associated nerve located in the adventitia of the artery. Nerve Satellite cell Neuron cell body </entry>
<entry linktype="AI" linkname="EUR-009-020" title="Figure 9.20: Meissner's Plexus, Esophagus, x.s., Pig">Meissner's Plexus, Esophagus, x.s., Pig. These parasympathetic plexuses are located in the submucosa of the digestive tract. Note the characteristic large OowlOs eyeO nucleus of the neurons. Plexus Neuron cell body Neuron cell body Muscularis mucosae Submucosa Submucosa Muscularis externa, inner circular </entry>
<entry linktype="AI" linkname="EUR-009-021" title="Figure 9.21: Auerbach's Plexus, Jejunum, l.s., Dog">Auerbach's Plexus, Jejunum, l.s., Dog. These parasympathetic plexuses are located between the inner circular and outer longitudinal layers of the muscularis externa of the digestive tract. Plexus Neuron cell body Neuron cell body Muscularis externa, inner circular Muscularis externa, outer longitudinal </entry>
<entry linktype="AI" linkname="EUR-009-022" title="Figure 9.22: Nerve, Myelinated, x.s., Pig (Masson's)">Nerve, Myelinated, x.s., Pig (Masson's). The nerve shown is comprised of many fascicles bounded by a connective tissue sheath, the epineurium. Each fascicle is surrounded by a perineurium and contains numerous axons. A magnified view of a nerve fascicle in this preparation is shown in Figure 9.23. Adipose tissue Epineurium Adipose tissue Perineurium Perineurium Epineurium </entry>
<entry linktype="AI" linkname="EUR-009-023" title="Figure 9.23: Nerve Fascicle (portion), Myelinated, x.s., Pig (Masson's)">Nerve Fascicle (portion), Myelinated, x.s., Pig (Masson's). Magnified view of one of the nerve fascicles shown in Figure 9.22. Delicate connective tissue fibers of the endoneurium are visible around individual myelinated axons. Space artifact Endoneurium Myelin sheath Endoneurium Axon Axon Axon Axon Axon Myelin sheath Space artifact Myelin sheath Axon Endoneurium Myelin sheath Space artifact Myelin sheath Space artifact </entry>
<entry linktype="AI" linkname="EUR-009-024" title="Figure 9.24: Nerve, Myelinated, Thoracic Wall, Cat">Nerve, Myelinated, Thoracic Wall, Cat. Myelin sheaths (pink) often present a scalloped or vacuolated appearance, an artifact of processing. Axons in this preparation are round, oval, or shriveled and either blue-gray or purple. Myelin sheath Myelin sheath Axon Axon Schwann cell, nucleus Axon Axon Schwann cell, nucleus Perineurium Myelin sheath </entry>
<entry linktype="AI" linkname="EUR-009-025" title="Figure 9.25: Axons, Myelinated, Medulla, Horse (Hagguist)">Axons, Myelinated, Medulla, Horse (Hagguist). Axons (blue) with myelin sheaths (pink) are seen in longitudinal sections and cross sections. Axon Myelin sheath Axon Myelin sheath Axon Axon Myelin sheath Axon </entry>
<entry linktype="AI" linkname="EUR-009-026" title="Figure 9.26: Nerve Fascicles, Unmyelinated, Ureter, Pig">Nerve Fascicles, Unmyelinated, Ureter, Pig. Note the wavy appearance of the fibers that have been cut longitudinally. See Figures 9.27 and 9.28 for comments on the relationship of unmyelinated axons to Schwann cells. Blood vessel Nerve fibers, l.s. Schwann cell, nucleus Schwann cell, nucleus Nerve fibers, x.s. Perineurium Blood vessel Nerve fibers, l.s. Nerve fibers, x.s. Schwann cell, nucleus Schwann cell, nucleus Perineurium </entry>
<entry linktype="AI" linkname="EUR-009-027" title="Figure 9.27: Schwann Cell With Unmyelinated Axons">Schwann Cell With Unmyelinated Axons. Unmyelinated axons of the peripheral nervous system are enveloped by Schwann cells. A Schwann cell may have 20 or more grooves in its surface, each groove containing one or more axons. Axon Schwann cell, nucleus Groove in plasma membrane of Schwann cell Axon Axon Groove in plasma membrane of Schwann cell </entry>
<entry linktype="AI" linkname="EUR-009-028" title="Figure 9.28: Nerve Fascicle (portion), Unmyelinated, Left Ventricle, Pig">Nerve Fascicle (portion), Unmyelinated, Left Ventricle, Pig. Each Schwann cell enwraps several unmyelinated axons within grooves (which appear as vesicles in cross section) of its plasma membrane. Axons can be seen filling some of the grooves, while in other grooves the axons have shrunken from the plasma membrane of the Schwann cell. Unmyelinated axons are typically smaller in diameter than myelinated axons. Groove in plasma membrane of Schwann cell Axon Schwann cell, nucleus Groove in plasma membrane of Schwann cell Axon Groove in plasma membrane of Schwann cell Axon Schwann cell, nucleus Axon Axon Axon Groove in plasma membrane of Schwann cell </entry>
<entry linktype="AI" linkname="EUR-009-029" title="Figure 9.29: Pacinian Corpuscle, Wholemount, Mesentery, Cat (Carmine)">Pacinian Corpuscle, Wholemount, Mesentery, Cat (Carmine). Two Pacinian corpuscles (one on the right somewhat distorted) are shown. Each is surrounded by a capsule of connective tissue within which are located concentric laminae of flattened cells that form the core. A nerve ending courses through the center of the corpuscle. The closely packed inner core cells surround the nerve. The peripheral laminae form a looser, outer core. Capsule Outer core Inner core Mesenteric blood vessel Nerve </entry>
<entry linktype="AI" linkname="EUR-009-030" title="Figure 9.30: Pacinian Corpuscle, x.s., Pancreas, Cat">Pacinian Corpuscle, x.s., Pancreas, Cat. The Pacinian corpuscle is frequently seen in the pancreas of carnivores. See Figure 9.29 for description. Pancreas Nerve Inner core Capsule Outer core </entry>
<entry linktype="AI" linkname="EUR-009-031" title="Figure 9.31: Small Encapsulated Nerve Endings, Dermis, Planum, Cow">Small Encapsulated Nerve Endings, Dermis, Planum, Cow. Numerous encapsulated sensory nerve endings occur in the dermis of the planum near the epithelium. Arteriovenous shunt Nerve Capsule Nerve </entry>
<entry linktype="AI" linkname="EUR-009-032" title="Figure 9.32: Neuromuscular Spindle, x.s., Thoracic Muscle, Cat">Neuromuscular Spindle, x.s., Thoracic Muscle, Cat. A neuromuscular spindle is a proprioceptor located within a muscle. It consists of sensory and motor nerve endings and intrafusal fibers, which are narrow, modified skeletal muscle cells. Nuclear chain fibers are intrafusal fibers with a single row of nuclei, whereas nuclear bag fibers are intrafusal fibers that contain many closely packed nuclei. A capsule encloses the fluid-filled space that surrounds the intrafusal fibers. Nuclear bag fiber Capsule Nuclear chain fiber Fluid-filled space Skeletal muscle cell, x.s. </entry>
<entry linktype="AI" linkname="EUR-009-033" title="Figure 9.33: Glycogen Body, Lumbosacral Enlargement, Spinal Cord, x.s., Chicken">Glycogen Body, Lumbosacral Enlargement, Spinal Cord, x.s., Chicken. The glycogen body is found only in birds. It consists of polyhedral, vesicular cells, each containing a central mass of glycogen and a peripherally displaced nucleus. Glycogen body Gray matter Gray matter Multipolar neurons Central canal Multipolar neurons White matter White matter </entry>
<entry linktype="AI" linkname="EUR-009-034" title="Figure 9.34: Glycogen Body, Lumbosacral Enlargement, Spinal Cord, x.s., Chicken">Glycogen Body, Lumbosacral Enlargement, Spinal Cord, x.s., Chicken. Cells of the glycogen body in detail. See Figure 9.33 for description. Cell of glycogen body Central canal Cell of glycogen body White matter </entry>
<entry linktype="AI" linkname="EUR-009-035" title="Figure 9.35: Dorsal Root Ganglion, Lumbosacral Enlargement, Spinal Cord, x.s., Chicken">Dorsal Root Ganglion, Lumbosacral Enlargement, Spinal Cord, x.s., Chicken. Portions of the spinal cord, ventral root of a spinal nerve, dorsal root ganglion, and vertebra. Gray matter White matter Space artifact Dorsal root ganglion Bone Multipolar neuron Ventral root </entry>
<entry linktype="AI" linkname="EUR-009-037" title="Figure 9.37: Herbst Corpuscle, Upper Beak, x.s., Chicken">Herbst Corpuscle, Upper Beak, x.s., Chicken. These encapsulated nerve endings occur frequently in the skin of the bird. They are similar to Pacinian corpuscles of mammals and consist of an outer capsule of connective tissue, a laminated core, and an axial sensory nerve ending. Sharpey's fibers Bone Sharpey's fibers Nerve Corel Capsule of Herbst corpuscle </entry>
<entry linktype="AI" linkname="EUR-009-038" title="Figure 9.38: Herbst Corpuscle, Skin, Neck, Chicken">Herbst Corpuscle, Skin, Neck, Chicken. The Herbst corpuscles associated with follicles of feathered skin are sausage-shaped Dermis Epidermis Capsule of Herbst corpuscle Muscle (moves feather) Nerve Muscle (moves feather) </entry>
<entry linktype="AI" linkname="EUR-010-002" title="Figure 10.2: Capillary, l.s., Lamina Propria, Duodenum, Sheep">Capillary, l.s., Lamina Propria, Duodenum, Sheep. Erythrocytes are lined up in the lumen of this capillary. Endothelial cell, nucleus Erythrocytes Mast cell 9 9 </entry>
<entry linktype="AI" linkname="EUR-010-003" title="Figure 10.3: Arterioles and Venules, Eyelid, Pig">Arterioles and Venules, Eyelid, Pig. Small blood vessels of various sizes are present in the dermis. Small vein Arteriole, x.s. Arteriole, x.s. Small vein Small artery, x.s. Arteriole, x.s. </entry>
<entry linktype="AI" linkname="EUR-010-004" title="Figure 10.4: Arterioles, x.s., Endometrium, Uterus, Dog">Arterioles, x.s., Endometrium, Uterus, Dog. The smallest of the arterioles shown have only one layer of smooth muscle in their walls. Arteriole, x.s. Arteriole, x.s. Endothelial cell, nucleus Endothelial cell, nucleus Macrophage Macrophage </entry>
<entry linktype="AI" linkname="EUR-010-005" title="Figure 10.5: Venule, l.s., Connective Tissue, Epiglottis, Goat">Venule, l.s., Connective Tissue, Epiglottis, Goat. The wall of the venule consists of an endothelium surrounded by a small amount of connective tissue. Endothelial cell, surface cut Erythrocytes Endothelial cell, nucleus </entry>
<entry linktype="AI" linkname="EUR-010-006" title="Figure 10.6: Arterioles and Venule, l.s., Submucosa, Esophagus, Cat">Arterioles and Venule, l.s., Submucosa, Esophagus, Cat. The circular arrangement of the smooth muscle of the tunica media can be seen in the region where the arterioles have been cut tangentially. Tunica media Tunica adventitia Tunica adventitia Venule Arteriole Endothelial cell, nucleus Tunica media Arteriole </entry>
<entry linktype="AI" linkname="EUR-010-007" title="Figure 10.7: Small Artery and Vein, x.s., Eyelid, Pig">Small Artery and Vein, x.s., Eyelid, Pig. These vessels are surrounded by portions of sweat glands in the dermis. Veins such as the one shown often have an irregular or collapsed lumen. Sweat gland Tunica media Small artery, x.s. Internal elastic membrane Tunica adventitia Small vein, collapsed, x.s. </entry>
<entry linktype="AI" linkname="EUR-010-008" title="Figure 10.8: Small Artery, l.s., Esophagus, Pig">Small Artery, l.s., Esophagus, Pig. Endothelial cell, nucleus Tunica adventitia Skeletal muscle Tunica media Tunica media </entry>
<entry linktype="AI" linkname="EUR-010-009" title="Figure 10.9: Small Vein with Valve, l.s., Nose, Sheep">Small Vein with Valve, l.s., Nose, Sheep. Valves are thin flaps of connective tissue covered on both sides by an endothelium. Erythrocytes Valve Tunica adventitia Tunica media Endothelial cell, nucleus Plasma </entry>
<entry linktype="AI" linkname="EUR-010-010" title="Figure 10.10: Small Artery, x.s., with Branch, Subcutis, Dog">Small Artery, x.s., with Branch, Subcutis, Dog. Tunica adventitia Tunica media Tunica media Endothelial cell, nucleus Internal elastic membrane </entry>
<entry linktype="AI" linkname="EUR-010-011" title="Figure 10.11: Small Artery, Vein, and Nerve, x.s., Pancreas, Cat">Small Artery, Vein, and Nerve, x.s., Pancreas, Cat. Note that both of the vessels have a sparse adventitia. Artery External elastic membrane Nerve fascicle, unmyelinated Adipose tissue Internal elastic membrane Tunica adventitia Tunica adventitia Vein Tunica media Tunica media Pancreas Adipose tissue </entry>
<entry linktype="AI" linkname="EUR-010-012" title="Figure 10.12: Artery and Vein, x.s., Wattle, Rooster">Artery and Vein, x.s., Wattle, Rooster. Note the especially thick tunica media of the artery. Artery Tunica media Tunica adventitia Tunica adventitia Vein Tunica media Tunica intima, endothelium Erythrocytes </entry>
<entry linktype="AI" linkname="EUR-010-013" title="Figure 10.13: Medium Artery, x.s., Lymph Node, Pig">Medium Artery, x.s., Lymph Node, Pig. The rich pink color of the elastic fibers contrasts with the paler pink of the collagenous fibers and smooth muscle. Internal elastic membrane Tunica intima, endothelium Tunica media Elastic fiber Elastic fiber Elastic fiber Tunica adventitia Nerve fascicle, unmyelinated </entry>
<entry linktype="AI" linkname="EUR-010-014" title="Figure 10.14: Medium Artery, x.s., Lymph Node, Pig (Orcein)">Medium Artery, x.s., Lymph Node, Pig (Orcein). Elastic fibers are stained reddish brown with orcein. Internal elastic membrane Elastic fiber Elastic fiber Elastic fiber </entry>
<entry linktype="AI" linkname="EUR-010-015" title="Figure 10.15: Medium Vein, l.s., Lymph Node, Pig">Medium Vein, l.s., Lymph Node, Pig. This vein accompanied the artery in Figures 10.13 and 10.14. Tunica media Adipose tissue Tunica adventitia Nerve fascicle, unmyelinated Tunica intima, endothelium </entry>
<entry linktype="AI" linkname="EUR-010-016" title="Figure 10.16: Medium Vein, l.s., Lymph Node, Pig (Orcein)">Medium Vein, l.s., Lymph Node, Pig (Orcein). Elastic fibers are stained reddish brown with orcein. Adipose tissue Tunica intima, endothelium Tunica media Tunica adventitia </entry>
<entry linktype="AI" linkname="EUR-010-017" title="Figure 10.17: Medium Artery, x.s., Lymph Node, Cat">Medium Artery, x.s., Lymph Node, Cat. Longitudinally oriented smooth muscle is present in the tunica intima between the endothelium and internal elastic membrane. Tunica intima, endothelium Internal elastic membrane Tunica media External elastic membrane Tunica adventitia Nerve fascicle, unmyelinated </entry>
<entry linktype="AI" linkname="EUR-010-018" title="Figure 10.18: Renal Artery, Near Aorta, x.s., Pig">Renal Artery, Near Aorta, x.s., Pig. Note both an inner and outer layer of smooth muscle in the tunica media. The inner layer is arranged longitudinally. Tunica media Internal elastic membrane Tunica media Tunica intima, endothelium Tunica adventitia </entry>
<entry linktype="AI" linkname="EUR-010-019" title="Figure 10.19: Portal Vein, x.s., Dog">Portal Vein, x.s., Dog. Note the bundles of longitudinally arranged smooth muscle in the tunica adventitia, a characteristic of large veins. Tunica adventitia Tunica adventitia Tunica adventitia Tunica media Tunica intima, endothelium </entry>
<entry linktype="AI" linkname="EUR-010-020" title="Figure 10.20: Vein with Valves, x.s., Lip, Pig">Vein with Valves, x.s., Lip, Pig. Portions of two leaflets of a valve extend into the lumen of this vein. Tunica adventitia Tunica intima, endothelium Valve Tunica media </entry>
<entry linktype="AI" linkname="EUR-010-021" title="Figure 10.21: Umbilical Artery (Right) and Vein (Left), x.s., Horse (Masson's)">Umbilical Artery (Right) and Vein (Left), x.s., Horse (Masson's). The tunica media of the umbilical artery is thicker than that of the umbilical vein. Tunica intima, endothelium Tunica adventitia Tunica media Tunica adventitia Tunica intima, endothelium Tunica media </entry>
<entry linktype="AI" linkname="EUR-010-022" title="Figure 10.22: Umbilical Artery, x.s., Horse (Masson's)">Umbilical Artery, x.s., Horse (Masson's). The umbilical artery lacks an internal elastic membrane. The innermost smooth muscle cells of the tunica media are epithelioid (epithelial-like) and oriented longitudinally. Tunica media Tunica intima, endothelium Epithelioid cells </entry>
<entry linktype="AI" linkname="EUR-010-023" title="Figure 10.23: Glomus, Nose, Pig">Glomus, Nose, Pig. The highly convoluted anastomotic artery, surrounding connective tissue, and nerves forming this organized arteriovenous anastomosis can be seen. 4 Anastomotic artery Anastomotic artery Anastomotic artery 4 </entry>
<entry linktype="AI" linkname="EUR-010-024" title="Figure 10.24: Arteriovenous Anastomosis, x.s., Lip, Pig">Arteriovenous Anastomosis, x.s., Lip, Pig. Longitudinally directed cells of smooth muscle of the tunica media are characteristically epithelioid (epithelial-like) in an anastomotic artery. These arteries lack an internal elastic membrane and have a small lumen. Tunica adventitia Tunica intima, endothelium Epithelioid cells </entry>
<entry linktype="AI" linkname="EUR-010-025" title="Figure 10.25: Aorta (Left) and Pulmonary Artery (Right), x.s., Pig (Orcein)">Aorta (Left) and Pulmonary Artery (Right), x.s., Pig (Orcein). This preparation was stained with orcein to highlight elastic tissue <i>(red-brown).</i> Aorta, lumen Tunica adventitia Tunica media Tunica media Tunica intima Pulmonary artery, lumen Tunica intima </entry>
<entry linktype="AI" linkname="EUR-010-026" title="Figure 10.26: Aorta, x.s., Dog (Orcein)">Aorta, x.s., Dog (Orcein). This specimen was stained with orcein to emphasize elastic tissue <i>(red-brown).</i> Tunica intima, endothelium Tunica media </entry>
<entry linktype="AI" linkname="EUR-010-027" title="Figure 10.27: Pulmonary Artery, x.s., Sheep">Pulmonary Artery, x.s., Sheep. Portion of the tunica intima and tunica media. Smooth muscle of the tunica media is oriented in various directions. Wavy, pink elastic fibers occur among the smooth muscle. Smooth muscle Smooth muscle Elastic fibers Tunica intima, endothelium </entry>
<entry linktype="AI" linkname="EUR-010-028" title="Figure 10.28: Vena Cava, x.s., Dog">Vena Cava, x.s., Dog. This section was taken from a region near the heart. The tunica adventitia consists largely of cardiac muscle and adipose tissue. Tunica intima, endothelium Adipose tissue Tunica media Cardiac muscle Cardiac muscle Adipose tissue Vasa vasorum </entry>
<entry linktype="AI" linkname="EUR-010-029" title="Figure 10.29: Right Auricle, Pig (Orcein)">Right Auricle, Pig (Orcein). The section was stained with orcein to show the distribution of elastic fibers <i>(red-brown).</i> Endocardium Myocardium Smooth muscle Elastic fibers Elastic fibers </entry>
<entry linktype="AI" linkname="EUR-010-030" title="Figure 10.30: Right Auricle, Pig (Mallory's)">Right Auricle, Pig (Mallory's). This preparation shows the distribution of smooth muscle in the endocardium. Endocardium Myocardium Smooth muscle Myocardium Collagenous fibers </entry>
<entry linktype="AI" linkname="EUR-010-031" title="Figure 10.31: Pulmonic (Semilunar) Valve, x.s., Dog">Pulmonic (Semilunar) Valve, x.s., Dog. Pulmonic valves are located in the pulmonary artery near the heart. The section shows a portion of the fibrous cardiac skeleton. Pulmonary artery, lumen Valve Cardiac skeleton, fibrous Pulmonary artery, lumen Tunica media Adipose tissue </entry>
<entry linktype="AI" linkname="EUR-010-032" title="Figure 10.32: Pulmonic (Semilunar) Valve, x.s., Dog (Masson's)">Pulmonic (Semilunar) Valve, x.s., Dog (Masson's). Portions of two adjacent pulmonic valves are visible. The connective tissue of the valves and the tunica media of the pulmonary artery blend with the fibrous cardiac skeleton. A cushion of mesenchyme-like connective tissue lies adjacent to the cardiac skeleton. Valve Valve Mesenchyme-like tissue Cardiac skeleton, fibrous Mesenchyme-like tissue Tunica intima, endothelium Tunica media Tunica adventitia Adipose tissue Tunica adventitia </entry>
<entry linktype="AI" linkname="EUR-010-033" title="Figure 10.33: Pulmonic (Semilunar) Valve, x.s., Dog">Pulmonic (Semilunar) Valve, x.s., Dog. The valve consists of a core of dense irregular connective tissue sandwiched between two layers of endothelium. Valve Tunica intima, endothelium Mesenchyme-like tissue Tunica media Mesenchyme-like tissue Cardiac skeleton, fibrous </entry>
<entry linktype="AI" linkname="EUR-010-034" title="Figure 10.34: Pulmonic (Semilunar) Valve, x.s., Dog">Pulmonic (Semilunar) Valve, x.s., Dog. A portion of the atrial wall, pulmonary artery, aorta, and cardiac skeleton (cartilaginous and fibrous) are visible. Pulmonary artery, lumen Valve Pulmonary artery, lumen Atrium, myocardium Cardiac skeleton, cartilaginous Cardiac skeleton, cartilaginous Cardiac skeleton, fibrous Aorta, lumen </entry>
<entry linktype="AI" linkname="EUR-010-035" title="Figure 10.35: Cardiac Skeleton, Dog">Cardiac Skeleton, Dog. The cartilaginous portion of the cardiac skeleton of the dog is formed from fibrocartilage containing numerous scattered chondrocytes. Chondrocyte Chondrocyte </entry>
<entry linktype="AI" linkname="EUR-010-036" title="Figure 10.36: Purkinje Cells, x.s. and l.s., Left Ventricle, Goat">Purkinje Cells, x.s. and l.s., Left Ventricle, Goat. Myofibrils are limited to the periphery of these large, modified cardiac muscle cells. Purkinje cell, l.s. Myofibrils Purkinje cell, x.s. Purkinje cell, x.s. Purkinje cell, l.s. Myofibrils Purkinje cell, l.s. </entry>
<entry linktype="AI" linkname="EUR-010-037" title="Figure 10.37: Visceral and Parietal Pericardium, Cat">Visceral and Parietal Pericardium, Cat. The pericardium consists of a mesothelium (simple squamous epithelium) and underlying connective tissue. The mesothelium of the visceral pericardium (epicardium) covers the surface of the heart. The remainder of the pericardial cavity is lined by the mesothelium of the parietal pericardium. Pericardium, visceral Adipose tissue Pericardium, parietal Pericardial cavity Myocardium, right ventricle </entry>
<entry linktype="AI" linkname="EUR-010-038" title="Figure 10.38: Aortic Body, Pig">Aortic Body, Pig. The aortic body is located between the pulmonary artery and aorta. It is a small, encapsulated structure containing blood vessels, nerves, and two types of parenchyma cells (see Figure 10.39). Neuron cell body Nerve fascicle, unmyelinated Arteriole Parenchyma cells Parenchyma cells </entry>
<entry linktype="AI" linkname="EUR-010-039" title="Figure 10.39: Aortic Body, Pig">Aortic Body, Pig. Two types of parenchyma cells can be distinguished in the aortic body. The type I (glomus) cell has a round nucleus and a granular cytoplasm. The type II (sustentacular) cell has few or no cytoplasmic granules and an oval nucleus. Type I cells usually occur in clusters surrounded by Type II cells and connective tissue. Arteriole Type II cell Type I cell Type I cell Nerve fascicle, unmyelinated Type I cell Type II cell </entry>
<entry linktype="AI" linkname="EUR-010-040" title="Figure 10.40: Lymphatic Vessel with Valve, Artery, and Vein, Cecal Tonsil, Chicken">Lymphatic Vessel with Valve, Artery, and Vein, Cecal Tonsil, Chicken. Lymphatic vessels have a large lumen and a relatively thin wall. Valves may be present. Cecum, wall Valve Lymphatic vessel Vein Plasma Erythrocytes Adipose tissue Artery </entry>
<entry linktype="AI" linkname="EUR-010-041" title="Figure 10.41: Lymphatic Vessel with Valve, Lymph Node, Pig">Lymphatic Vessel with Valve, Lymph Node, Pig. The valves of lymphatic vessels consist of a connective tissue core surrounded on each side by an endothelium. Valve Lymph Adipose tissue </entry>
<entry linktype="AI" linkname="EUR-010-042" title="Figure 10.42: Large Lymphatic Vessel, Submucosa, Cecum, Horse">Large Lymphatic Vessel, Submucosa, Cecum, Horse. The wall of the lymphatic vessel consists of an endothelium surrounded by a small amount of connective tissue. The latter blends with the connective tissue of the submucosa. Arteriole Arteriole Venule Endothelium Lymph </entry>
<entry linktype="AI" linkname="EUR-011-001" title="Figure 11.1: Lymphatic Nodules and Diffuse Lymphatic Tissue, Pyloric Stomach, Cat">Lymphatic Nodules and Diffuse Lymphatic Tissue, Pyloric Stomach, Cat. Dense aggregations of lymphocytes form lymphatic nodules in the lamina propria. Diffuse lymphatic tissue Mucosa Submucosa Muscularis externa Lymphatic nodule Germinal center </entry>
<entry linktype="AI" linkname="EUR-011-002" title="Figure 11.2: Lymphatic Nodules and Diffuse Lymphatic Tissue, Colon, x.s., Pig">Lymphatic Nodules and Diffuse Lymphatic Tissue, Colon, x.s., Pig. The mucosa and submucosa contain diffuse lymphatic tissue and large lymphatic nodules with germinal centers. Lymphatic nodules are especially numerous in the digestive tract of the pig. Diffuse lymphatic tissue Lymphatic nodule Diffuse lymphatic tissue Mucosa Submucosa Corona Diffuse lymphatic tissue Submucosa Germinal center </entry>
<entry linktype="AI" linkname="EUR-011-003" title="Figure 11.3: Lymphatic Nodule, Colon, Pig">Lymphatic Nodule, Colon, Pig. Cells of the germinal center and corona. Many small lymphocytes occur in the peripheral corona; fewer and larger cells are seen in the germinal center. Lymphocyte, large Germinal center Lymphocyte, large Lymphocyte, small Reticular cell Corona </entry>
<entry linktype="AI" linkname="EUR-011-004" title="Figure 11.4: Lymphatic Nodule, Colon, Pig">Lymphatic Nodule, Colon, Pig. Detail of cells of the germinal center and corona. Small lymphocytes are characterized by a heterochromatic nucleus and scant cytoplasm. Lymphocyte, large Corona Germinal center Lymphocyte, small </entry>
<entry linktype="AI" linkname="EUR-011-005" title="Figure 11.5: Peyer's Patch, Ileum, x.s., Cat">Peyer's Patch, Ileum, x.s., Cat. A Peyer's patch is an aggregation of lymphatic nodules in the lamina propria and submucosa of the small intestine. Lymphatic nodule Villus </entry>
<entry linktype="AI" linkname="EUR-011-006" title="Figure 11.6: Peyer's Patch, Ileum, x.s., Dog">Peyer's Patch, Ileum, x.s., Dog. Eight lymphatic nodules of a portion of a Peyer's patch are visible in this section. Villus Villus Diffuse lymphatic tissue Diffuse lymphatic tissue Lymphatic nodule Muscularis externa Submucosa </entry>
<entry linktype="AI" linkname="EUR-011-007" title="Figure 11.7: Paraepiglottic Tonsil, Larynx, l.s., Cat">Paraepiglottic Tonsil, Larynx, l.s., Cat. In the cat an accumulation of lymphatic tissue in the lateral wall of the larynx, between the epiglottis and the vestibular fold, forms a tonsil without crypts. Epiglottis Stratified squamous epithelium, tonsil Lymphatic nodule Diffuse lymphatic tissue Diffuse lymphatic tissue Vestibular fold </entry>
<entry linktype="AI" linkname="EUR-011-008" title="Figure 11.8: Palatine Tonsil, Dog">Palatine Tonsil, Dog. In the dog the entire tonsil lies within a fossa (a small hollow) and is covered in part by a semilunar fold. The palatine tonsils of carnivores lack crypts. Lymphatic nodule Stratified squamous epithelium, semilunar fold Stratified squamous epithelium, tonsil Fossa semilunar fold Salivary glands Skeletal muscle </entry>
<entry linktype="AI" linkname="EUR-011-009" title="Figure 11.9: Palatine Tonsil, Dog">Palatine Tonsil, Dog. A portion of a tonsil and semilunar fold. Stratified squamous epithelium, semilunar fold Salivary glands Lymphatic nodule Fossa semilunar fold Stratified squamous epithelium, tonsil Diffuse lymphatic tissue </entry>
<entry linktype="AI" linkname="EUR-011-010" title="Figure 11.10: Palatine Tonsil, Dog">Palatine Tonsil, Dog. Mixed salivary glands are associated with the wall of the tonsils in carnivores. In other species only mucous glands are present. Serous acinus Serous demilune Mucous acinus Serous demilune </entry>
<entry linktype="AI" linkname="EUR-011-011" title="Figure 11.11: Palatine Tonsil, Horse">Palatine Tonsil, Horse. The palatine tonsils of noncarnivores have crypts (surface invaginations lined by stratified squamous epithelium). Lymphatic nodule Stratified squamous epithelium Crypt Salivary glands, mucous Crypt </entry>
<entry linktype="AI" linkname="EUR-011-012" title="Figure 11.12: Palatine Tonsil, Horse">Palatine Tonsil, Horse. Note that the continuity of each crypt with the surface is not always evident. Stratified squamous epithelium Crypt Crypt Diffuse lymphatic tissue Lymphatic nodule </entry>
<entry linktype="AI" linkname="EUR-011-013" title="Figure 11.13: Palatine Tonsil, Horse">Palatine Tonsil, Horse. Lymphocytes and other leukocytes have infiltrated and partly obliterated the epithelial lining of this crypt. Leukocyte infiltration Stratified squamous epithelium Crypt Stratified squamous epithelium Leukocyte infiltration Leukocyte infiltration Stratified squamous epithelium Crypt Stratified squamous epithelium Leukocyte infiltration </entry>
<entry linktype="AI" linkname="EUR-011-014" title="Figure 11.14: Lymph Node, Cow">Lymph Node, Cow. The lymph node is surrounded by a capsule. Trabeculae project inward from the capsule. The cortex contains sinuses, diffuse lymphatic tissue, and lymphatic nodules. The medulla is composed of medullary cords and sinuses. Capsule Lymphatic nodule Diffuse lymphatic tissue Trabecula Medullary sinus Medullary cord Deep cortex Deep cortex Diffuse lymphatic tissue Lymphatic nodule Cortical sinus Subcapsular sinus </entry>
<entry linktype="AI" linkname="EUR-011-015" title="Figure 11.15: Lymph Node, Dog">Lymph Node, Dog. This histologic section of a lymph node at low magnification shows the same features as the drawing in Figure 11.14. Trabecula Medullary sinus Medullary sinus Medullary cord Deep cortex Medullary cord Lymphatic nodule Capsule Subcapsular sinus Cortical sinus </entry>
<entry linktype="AI" linkname="EUR-011-016" title="Figure 11.16: Tracheobronchial Lymph Node, Dog">Tracheobronchial Lymph Node, Dog. This lymph node is adjacent to the wall of a primary bronchus near the tracheal bifurcation. Primary bronchus, lumen Cartilage plate, bronchus Cortex, lymph node Medulla, lymph node </entry>
<entry linktype="AI" linkname="EUR-011-017" title="Figure 11.17: Lymph Node, Horse">Lymph Node, Horse. The arrangement of cortical and medullary tissues may be atypical in some of the lymph nodes of mammals. In the example shown the distribution of cortical and medullary components is the reverse of that commonly expected. Capsule ?? Medullary cord Cortical tissue Lymphatic nodule Lymphatic nodule </entry>
<entry linktype="AI" linkname="EUR-011-018" title="Figure 11.18: Lymph Node, Horse">Lymph Node, Horse. Not only is the arrangement of cortical and medullary components reversed in this section, but the proportion of the medullary tissue is much greater than usual. Capsule Medullary cord Medullary sinus Cortical tissue </entry>
<entry linktype="AI" linkname="EUR-011-019" title="Figure 11.19: Lymph Node, Pig">Lymph Node, Pig. The lymph nodes of pigs consistently show an atypical pattern. In this section cortical tissue is predominantly central, while medullary tissue occurs both superficially and internally. Lymphatic nodule Diffuse lymphatic tissue Capsule Medullary sinus Medullary cord Diffuse lymphatic tissue Diffuse lymphatic tissue Lymphatic nodule Medullary sinus Medullary cord </entry>
<entry linktype="AI" linkname="EUR-011-020" title="Figure 11.20: Lymph Node, Cow">Lymph Node, Cow. The lymph node of the cow is often characterized by the presence of large lymphatic nodules. Lymphatic nodule Diffuse lymphatic tissue Medullary sinus Medullary cord Medullary sinus Medullary cord Capsule </entry>
<entry linktype="AI" linkname="EUR-011-021" title="Figure 11.21: Cortex, Lymph Node, Horse">Cortex, Lymph Node, Horse. The subcapsular sinus below the capsule continues as cortical sinuses that parallel the trabeculae through the cortex. Capsule Subcapsular sinus Subcapsular sinus Cortical sinus Trabecula </entry>
<entry linktype="AI" linkname="EUR-011-027" title="Figure 11.27: Deep Cortex, Lymph Node, Dog">Deep Cortex, Lymph Node, Dog. Postcapillary venules, l.s. and x.s. These vessels are lined by elongated cells that appear cuboidal in cross section. Lymphocytes migrate between the endothelial cells of the postcapillary venules. Lymphocyte Postcapillary venule, x.s. Lymphocyte Postcapillary venule, l.s. Postcapillary venule, l.s. Lymphocyte Diffuse lymphatic tissue </entry>
<entry linktype="AI" linkname="EUR-011-028" title="Figure 11.28: Cortex, Lymph Node, Horse">Cortex, Lymph Node, Horse. Multinucleate giant cells, derived from the coalescence of macrophages, are sometimes found in lymph nodes. Multinucleate giant cell Macrophage Multinucleate giant cell </entry>
<entry linktype="AI" linkname="EUR-011-031" title="Figure 11.31: Medulla, Lymph Node, Dog">Medulla, Lymph Node, Dog. Cellular medullary cords surround medullary sinuses that are lined incompletely by endothelial cells. A megakaryocyte is present in a medullary cord. Megakaryocyte Lymphocyte Endothelial cell, nucleus Medullary sinus Lymphocyte Medullary sinus Medullary cord Lymphocyte </entry>
<entry linktype="AI" linkname="EUR-011-032" title="Figure 11.32: Medulla, Lymph Node, Dog">Medulla, Lymph Node, Dog. Macrophages containing phagocytized erythrocytes are evident in the medullary sinuses. Granulocyte Granulocyte Reticular cell Endothelial cell, nucleus Macrophage with erythrocytes Lymphocyte Reticular cell Lymphocyte Medullary sinus Medullary cord Endothelial cell, nucleus Macrophage with erythrocytes </entry>
<entry linktype="AI" linkname="EUR-011-033" title="Figure 11.33: Hemal Node, Sheep">Hemal Node, Sheep. The general organization is much like that of a lymph node, but the sinuses are filled with blood. Lymphatic nodules are scarce, and trabeculae of connective tissue are not apparent. Capsule Diffuse lymphatic tissue Medullary sinus Medullary sinus Subcapsular sinus Adipose tissue Lymphatic nodule Subcapsular sinus </entry>
<entry linktype="AI" linkname="EUR-011-034" title="Figure 11.34: Hemal Node, Sheep">Hemal Node, Sheep. The subcapsular (marginal) sinus is filled with blood. Reticular cells of the sinus contain phagocytized material. Capsule Subcapsular sinus Erythrocytes Erythrocytes Reticular cell Diffuse lymphatic tissue </entry>
<entry linktype="AI" linkname="EUR-011-035" title="Figure 11.35: Spleen, Dog">Spleen, Dog. This drawing is of a small portion of the spleen. Capsule White pulp Red pulp Trabecula Red pulp Red pulp Central artery Lymphatic nodule Lymphatic nodule Trabecula Central artery </entry>
<entry linktype="AI" linkname="EUR-011-036" title="Figure 11.36: Spleen, Dog">Spleen, Dog. The parenchyma of the spleen is organized into red pulp and white pulp (periarterial lymphatic sheaths and lymphatic nodules). Trabeculae extend inward from the capsule and are seen throughout the red pulp. Red pulp Capsule Trabecula Central artery White pulp Trabecula Red pulp Red pulp Lymphatic nodule White pulp Central artery </entry>
<entry linktype="AI" linkname="EUR-011-037" title="Figure 11.37: Spleen, Dog">Spleen, Dog. Note the smooth muscle in the capsule and trabeculae. The spleen of the dog is a sinusal spleen, containing venous sinuses. See Figure 11.38. Red pulp Mesothelium Capsule Venous sinus Red pulp Ellipsoid Trabecula Ellipsoid </entry>
<entry linktype="AI" linkname="EUR-011-038" title="Figure 11.38: Spleen, Dog">Spleen, Dog. Venous sinuses are lined by longitudinally oriented, elongated endothelial cells. The nuclei may or may not be apparent in cross sections of such lining cells. Erythrocytes fill the sinuses and the spaces of the red pulp. Red pulp Trabecula Venous sinus Venous sinus 13 Ellipsoid </entry>
<entry linktype="AI" linkname="EUR-011-039" title="Figure 11.39: Spleen, Dog">Spleen, Dog. Ellipsoids can be seen in the marginal zone between the periarterial lymphatic sheath (white pulp) and the red pulp. They are also present in the red pulp. Marginal zone Red pulp Central artery Marginal zone Ellipsoid Lymphatic nodule Red pulp Marginal zone Ellipsoid Marginal zone </entry>
<entry linktype="AI" linkname="EUR-011-040" title="Figure 11.40: Spleen, Pig (Orcein)">Spleen, Pig (Orcein). The capsule and trabeculae are rich in elastic fibers (red-brown). Elastic fiber Capsule 8 8 Trabecula Trabecula </entry>
<entry linktype="AI" linkname="EUR-011-041" title="Figure 11.41: Spleen, Pig (Mallory's)">Spleen, Pig (Mallory's). Ellipsoids are abundant in the pig. They are especially numerous in the vicinity of the marginal zone of a periarterial lymphatic sheath. See Figure 11.44 for details of ellipsoids. Ellipsoid Ellipsoid Periarterial lymphatic sheath 8 Marginal zone Central artery Capsule Trabecula Trabecula Trabecula Ellipsoid Central artery Ellipsoid Ellipsoid </entry>
<entry linktype="AI" linkname="EUR-011-042" title="Figure 11.42: Capsule, Spleen, Horse">Capsule, Spleen, Horse. The capsule of the spleen of the horse and cow contains layers of smooth muscle oriented at right angles to each other, rather than being interwoven as in carnivores, pigs, sheep, and goats. In this preparation there are three distinct layers of muscle. Compare with Figures 11.37, 11.43, and 11.45. Smooth muscle </entry>
<entry linktype="AI" linkname="EUR-011-043" title="Figure 11.43: Capsule, Spleen, Cow">Capsule, Spleen, Cow. The capsule contains two thick layers of smooth muscle oriented at right angles to each other. Serosa Smooth muscle 8 </entry>
<entry linktype="AI" linkname="EUR-011-044" title="Figure 11.44: Spleen, Pig">Spleen, Pig. Ellipsoids are especially abundant in the spleen of the pig. Each consists of macrophages and reticular fibers that surround a capillary. Ellipsoid Capillary lumen Ellipsoid Ellipsoid Capillary lumen </entry>
<entry linktype="AI" linkname="EUR-011-045" title="Figure 11.45: Capsule, Spleen, Sheep">Capsule, Spleen, Sheep. In sheep the bulk of the capsule contains many interwoven smooth muscle cells. The smooth muscle in the capsule of the spleen of carnivores (Figure 11.37), pigs, and goats has a similar arrangement. In the horse (Figure 11.42) and cow (Figure 11.43) the muscle cells are arranged in layers instead. Elastic fibers can be observed as faint pink spirals. Serosa Smooth muscle Elastic fiber Lymphatic vessel Smooth muscle </entry>
<entry linktype="AI" linkname="EUR-011-046" title="Figure 11.46: Spleen, Sheep">Spleen, Sheep. Note the thick trabecula. Characteristically, the spleens of cows and sheep have thick trabeculae. Compare with Figure 11.41. White pulp White pulp Red pulp Trabecula </entry>
<entry linktype="AI" linkname="EUR-011-047" title="Figure 11.47: Red Pulp, Spleen, Sheep">Red Pulp, Spleen, Sheep. Wisps of smooth muscle are scattered throughout the red pulp. Smooth muscle Smooth muscle Smooth muscle </entry>
<entry linktype="AI" linkname="EUR-011-048" title="Figure 11.48: Thymus, Puppy">Thymus, Puppy. A thin capsule of connective tissue covers the thymus. Lobules, incompletely divided by connective-tissue septa, consist of an outer, dark cortex and an inner, pale medulla. The medulla is continuous between adjacent lobules. Cortex Capsule Septum Medulla Septum Cortex Medulla </entry>
<entry linktype="AI" linkname="EUR-011-049" title="Figure 11.49: Thymus, Puppy">Thymus, Puppy. Portion of the medulla and cortex. The cortex consists predominantly of small lymphocytes. The lymphocytes of the medulla are larger and less abundant. The medulla contains concentrically arranged, swollen, and keratinized reticular cells that form Hassall's corpuscles, which are characteristic of the thymus. White pulp Hassall’s corpuscle Medulla Hassall’s corpuscle </entry>
<entry linktype="AI" linkname="EUR-011-051" title="Figure 11.51: Cecal Tonsil, x.s., Chicken">Cecal Tonsil, x.s., Chicken. The accumulation of diffuse and nodular lymphatic tissue in the lamina propria and submucosa near the opening of each cecum is called the cecal tonsil. Villus Lymphatic nodule Lymphatic nodule Crypt of Lieberk├╝hn (intestinal gland) Crypt of Lieberk├╝hn (intestinal gland) Muscularis externa </entry>
<entry linktype="AI" linkname="EUR-011-052" title="Figure 11.52: Spleen, Chicken">Spleen, Chicken. Red pulp (pink) intermingles with white pulp (purple). The white pulp contains a few lymphatic nodules. Trabeculae of connective tissue are absent. Lymphatic nodule White pulp Red pulp Red pulp White pulp Blood vessel </entry>
<entry linktype="AI" linkname="EUR-011-053" title="Figure 11.53: Capsule, Spleen, Chicken">Capsule, Spleen, Chicken. Layers of smooth muscle make up a substantial part of the capsule. Connective tissue Mesothelium Connective tissue Smooth muscle of capsule Smooth muscle of capsule Erythrocyte Erythrocyte </entry>
<entry linktype="AI" linkname="EUR-011-054" title="Figure 11.54: Spleen, Chicken">Spleen, Chicken. Sheathed arteries, x.s., in white pulp. These vessels are lined by plump endothelial cells surrounded by reticular cells. Red pulp Erythrocyte Granulocyte Granulocyte White pulp 11 Sheathed artery, lumen Sheathed artery, lumen 11 White pulp </entry>
<entry linktype="AI" linkname="EUR-011-055" title="Figure 11.55: Thymus, Chicken">Thymus, Chicken. The thymus of the chicken is similar to that of mammals. The pale areas throughout the medullary regions of the lobules are called reticular structures (Figure 11.56). Septum Medulla Cortex Reticular structure Reticular structure Medulla Cortex Reticular structure </entry>
<entry linktype="AI" linkname="EUR-011-056" title="Figure 11.56: Medulla, Thymus, Chicken">Medulla, Thymus, Chicken. Myoid cells, cut obliquely, are characterized by a fibrous cytoplasm and peripheral nuclei. The pale-staining reticular structure in this section is considered a diffuse form of a Hassall's corpuscle. It consists of diffuse groups of reticular cells and scattered vesicles. The vesicles may contain eosinophilic material or degenerating cells. Myoid cell Reticular structure Vesicle Myoid cell </entry>
<entry linktype="AI" linkname="EUR-011-057" title="Figure 11.57: Bursa of Fabricius, Chicken">Bursa of Fabricius, Chicken. Portions of the long mucosal folds (plicae) project into the lumen of the bursa. Numerous follicles, each composed of a cortex and medulla, fill the lamina propria of each fold. Follicle Pseudostratified epithelium Follicle Bursa of Fabricius, lumen Pseudostratified epithelium Follicle Muscularis </entry>
<entry linktype="AI" linkname="EUR-011-058" title="Figure 11.58: Bursa of Fabricius, Chicken">Bursa of Fabricius, Chicken. Where the apex of a follicle contacts the epithelium, tall, pale columnar cells with apical nuclei form an epithelial tuft. Elsewhere, mucosal folds are covered by a pseudostratified columnar epithelium. Pseudostratified epithelium Epithelial tuft Lamina propria Undifferentiated epithelial cell Lamina propria Undifferentiated epithelial cell Medulla Cortex </entry>
<entry linktype="AI" linkname="EUR-011-059" title="Figure 11.59: Bursa of Fabricius, Chicken">Bursa of Fabricius, Chicken. A portion of a follicle. The darkly stained cortex is composed mostly of many small lymphocytes. The paler medulla contains fewer cells of various sizes. A layer of undifferentiated epithelial cells, which are cuboidal with an acidophilic cytoplasm, occupies the periphery of the medulla. A capillary network separates the cortex and the medulla. Capillary layer Medulla Undifferentiated epithelial cell Undifferentiated epithelial cell Cortex </entry>
<entry linktype="AI" linkname="EUR-012-001" title="Figure 12.1: Planum Nasale and Hairy Skin, Nose, Dog">Planum Nasale and Hairy Skin, Nose, Dog. Junction of the hairless planum nasale (thick skin) and the hairy portion (thin skin) of the nose. No glands are associated with the planum of carnivores. There are surface grooves in the planum of the dog. Surface groove Epithelium, planum Dermis Subcutis Hair follicle Sweat gland Epithelium, hairy skin </entry>
<entry linktype="AI" linkname="EUR-012-002" title="Figure 12.2: Planum Nasale and Hairy Skin, Nose, Cat">Planum Nasale and Hairy Skin, Nose, Cat. No hairs or glands are associated with the planum of carnivores. The surface of the planum bears numerous small, raised tubercles that are characteristic of the cat. Epidermal peg Dermal papilla Dermis Epithelium, planum Hair follicle Hair follicle Epithelium, hairy skin Sweat gland Subcutis </entry>
<entry linktype="AI" linkname="EUR-012-003" title="Figure 12.3: Epithelium, Planum Nasale, Cat">Epithelium, Planum Nasale, Cat. Portions of the small tubercles typical of the cat's planum. All layers of the epidermis are evident. Note how the papillae of the dermis interdigitate with the epidermal pegs. Stratum lucidum Stratum corneum Stratum granulosum Stratum spinosum Stratum spinosum Stratum granulosum Dermal papilla Stratum basale Epidermal peg Stratum spinosum Stratum basale </entry>
<entry linktype="AI" linkname="EUR-012-004" title="Figure 12.4: Nose, Horse">Nose, Horse. Numerous small sebaceous glands, sweat glands, fine hairs, and the follicle of a sinus hair are evident. The epidermis is heavily pigmented. Epidermis Dermis Sebaceous gland Sebaceous gland Dermis Hair follicle Sweat gland Hair follicle Sinus hair follicle Sweat gland </entry>
<entry linktype="AI" linkname="EUR-012-005" title="Figure 12.5: Nose, Horse">Nose, Horse. A melanocyte with numerous pigment granules is located in the deep portion of the epidermis. Surrounding cells have phagocytized melanin granules produced by melanocytes. The granules are aggregated like a cap just above the nucleus of some of the cells of the stratum spinosum. Dermis Melanocyte Stratum spinosum Intercellular bridges Intercellular bridges Stratum basale </entry>
<entry linktype="AI" linkname="EUR-012-006" title="Figure 12.6: Planum Rostrale, Pig">Planum Rostrale, Pig. The very thick epidermis of the snout of the pig has low, wide elevations and an especially thick stratum corneum. Long dermal papillae project into the epidermis. Numerous merocrine sweat glands occur in the subcutis. Hairs, which are sparse on the planum of the pig, are not shown. Stratum corneum Dermis Merocrine sweat gland Dermal papilla Epidermis Dermal papilla Dermis Merocrine sweat gland </entry>
<entry linktype="AI" linkname="EUR-012-007" title="Figure 12.7: Planum Rostrale, Pig">Planum Rostrale, Pig. Detail of the merocrine sweat glands. Secretory cells are either columnar or cuboidal and are surrounded by myoepithelial cells. Merocrine sweat gland Merocrine sweat gland Myoepithelial cell, nucleus Myoepithelial cell, nucleus </entry>
<entry linktype="AI" linkname="EUR-012-008" title="Figure 12.8: Planum Nasolabiale, Cow">Planum Nasolabiale, Cow. The surface of the planum of the cow is hairless and marked by grooves. Long dermal papillae project into the thick epidermis. Glands are abundant in the subcutis of the planum of ruminants. Surface groove Epidermis Dermal papilla Duct Dermis Nasolabial gland Duct </entry>
<entry linktype="AI" linkname="EUR-012-009" title="Figure 12.9: Planum Nasolabiale, Cow">Planum Nasolabiale, Cow. The tissue was cut parallel to the surface of the planum, so that cross sections of dermal papillae appear in the stratum spinosum. Each papilla is surrounded by cells of the stratum basale and each contains several blood vessels. Dermal papilla Stratum basale Stratum spinosum Stratum basale Stratum spinosum </entry>
<entry linktype="AI" linkname="EUR-012-010" title="Figure 12.10: Planum Nasolabiale, Cow">Planum Nasolabiale, Cow. During tissue processing, the keratinocytes of the stratum spinosum shrink away from each other, but remain attached at multiple sites where desmosomes are located. As a result of this artifact, there appear to be cytoplasmic connections between adjacent cells. Some early workers called these 'intercellular bridges' because they were thought to represent cytoplasmic connections between cells. Others thought the artifacts resembled spines, hence the name stratum spinosum. Intercellular bridges Keratinocyte nucleus Intercellular bridges </entry>
<entry linktype="AI" linkname="EUR-012-011" title="Figure 12.11: Planum Nasolabiale, Cow">Planum Nasolabiale, Cow. The planum of the cow, sheep, and goat contains many tubuloacinar serous glands. Branches of an intralobular duct can be seen entering secretory acini. Secretory acinus Intralobular duct </entry>
<entry linktype="AI" linkname="EUR-012-012" title="Figure 12.12: Digital Pad, Dog">Digital Pad, Dog. The digital pad is hairless and covered by a very thick epidermis that is roughened by small conical projections in the dog. Compare with Figure 12.14. Duct of sweat gland Duct of sweat gland Digital cushion Dermis, reticular layer Dermis, papillary layer </entry>
<entry linktype="AI" linkname="EUR-012-013" title="Figure 12.13: Digital Pad, Dog">Digital Pad, Dog. Coiled merocrine sweat glands and pacinian corpuscles among skeletal muscle and loose connective tissue of the digital pad. Skeletal muscle Merocrine sweat gland Pacinian corpuscle </entry>
<entry linktype="AI" linkname="EUR-012-014" title="Figure 12.14: Digital Pad, Cat">Digital Pad, Cat. The surface of the digital pad of the cat is smooth, lacking the conical papillae that are typical of the dog (Figure 12.12). Portions of the excretory ducts of sweat glands spiral through the stratified squamous epithelium. Dermis, papillary layer Dermis, reticular layer Digital cushion Duct of sweat gland Epidermis Duct of sweat gland Digital cushion </entry>
<entry linktype="AI" linkname="EUR-012-015" title="Figure 12.15: Digital Pad, Cat">Digital Pad, Cat. Detail of the epidermis and dermis shown in Figure 12.14. All five layers of the epidermis are evident. Dermis, papillary layer Stratum basale Stratum spinosum Stratum granulosum Stratum lucidum Stratum corneum </entry>
<entry linktype="AI" linkname="EUR-012-016" title="Figure 12.16: Skin, Mid-ventral Abdomen, Dog">Skin, Mid-ventral Abdomen, Dog. The epidermis is thin and consists of four layers. Note that only a few layers of cells comprise the stratum spinosum. The stratum corneum is also relatively thin, and the keratinized cells have loosened and separated from the surface. Hair, x.s. Dermis Stratum basale Stratum granulosum Stratum corneum Stratum spinosum </entry>
<entry linktype="AI" linkname="EUR-012-017" title="Figure 12.17: Skin, Back, Cat">Skin, Back, Cat. Two compound follicles are visible in the dermis. In carnivores the hairs of compound follicles merge at the level of the sebaceous glands and share a common follicular opening to the surface. Bits of hairs are evident in the follicles as shiny, yellow-brown structures. The arrector pill muscles of the skin of the back are especially well developed in cats and dogs. A space artifact separates the subcutis from the underlying skeletal muscle. Arrector pili muscle Arrector pili muscle Dermis, deep Dermis, superficial Epidermis Hair Hair bulb Skeletal muscle Subcutis </entry>
<entry linktype="AI" linkname="EUR-012-018" title="Figure 12.18: Skin, Caudal Abdomen, Cat">Skin, Caudal Abdomen, Cat. The epidermis is extremely thin. Cells of the stratum spinosum are sparse, and those of the stratum granulosum are visible only as occasional dark granular areas just beneath the stratum corneum. Hairs are visible within the compound follicles. Dermis, deep Dermis, superficial Hair Hair Hair Stratum basale Stratum corneum Stratum spinosum cell, nucleus </entry>
<entry linktype="AI" linkname="EUR-012-019" title="Figure 12.19: Skin, Back, Cat (Masson's)">Skin, Back, Cat (Masson's). Portions of an arrector pill muscle, sebaceous gland, and a hair within a follicle. Arrector pili muscle Dermis, deep Hair Sebaceous gland </entry>
<entry linktype="AI" linkname="EUR-012-021" title="Figure 12.21: Skin, Neck, Horse">Skin, Neck, Horse. Mid-region of a longitudinal section of a hair follicle. Large, clear cells of the medulla of the hair have round nuclei that become pyknotic as they progress distally from the hair bulb. The pigment-laden cortex of the hair is formed from closely packed elongated cells that have become keratinized. Scalelike, keratinized cells of the cuticle of the hair partially overlap so that their free edges point upward. They interlock with cells of the cuticle of the inner root sheath, whose free edges are directed downward. Connective tissue sheath 11 Outer root sheath Cuticle, inner root sheath Pyknotic nucleus Cortex, hair Medulla, hair Cuticle, inner root sheath Inner root sheath Connective tissue sheath Cuticle, hair Outer root sheath </entry>
<entry linktype="AI" linkname="EUR-012-022" title="Figure 12.22: Skin, Neck, Horse">Skin, Neck, Horse. A dermal papilla projects into the hair bulb at the base of the follicle. Cells of the cortex of the hair are nearly obscured by pigment granules provided by melanocytes of the bulb. Sweat gland Cortex, hair Outer root sheath Inner root sheath Medulla, hair Dermis Dermal papilla Sweat gland Connective tissue sheath </entry>
<entry linktype="AI" linkname="EUR-012-023" title="Figure 12.23: Skin, Dorsal Neck, Pig">Skin, Dorsal Neck, Pig. Note the extremely thick dermis. Sweat glands and adipose tissue are seen in the subcutis. Epidermis Dermis Sweat gland Adipose tissue Sweat gland </entry>
<entry linktype="AI" linkname="EUR-012-024" title="Figure 12.24: Skin, Dorsal Neck, Pig">Skin, Dorsal Neck, Pig. The epidermis and part of the dermis are shown in detail. Stratum corneum Stratum spinosum Stratum granulosum Dermis, superficial layer Stratum basale </entry>
<entry linktype="AI" linkname="EUR-012-025" title="Figure 12.25: Skin, Dorsal Neck, Pig (Orcein)">Skin, Dorsal Neck, Pig (Orcein). The dermis of the skin contains numerous branching elastic fibers. The fibers of the superficial layer are fine, while those of the deep layer are coarse. Dermis, superficial layer Epidermis Dermis, deep layer Elastic fiber Collagenous fiber Collagenous fiber Elastic fiber </entry>
<entry linktype="AI" linkname="EUR-012-026" title="Figure 12.26: Skin, Back, Sheep">Skin, Back, Sheep. Various portions of numerous hair follicles are embedded in the thick superficial layer of the dermis. The hair follicles of sheep tend to be arranged vertically, rather than diagonally, in the dermis. Compare with Figures 12.17 and 12.20. Dermis, superficial layer Sebaceous gland Epidermis Hair bulb Sweat gland Sweat gland Dermis, deep layer Hair bulb </entry>
<entry linktype="AI" linkname="EUR-012-027" title="Figure 12.27: Scrotum, Goat">Scrotum, Goat. The epidermis of the scrotum is remarkably thin. Portions of two simple hair follicles are located in the dermis. Bundles of smooth muscle among fibroelastic tissue in the dermis comprise the tunica dartos. Stratum corneum Hair Dermis, superficial layer Sebaceous gland Hair Sweat gland Dermis, deep layer Dartos muscle </entry>
<entry linktype="AI" linkname="EUR-012-028" title="Figure 12.28: Scrotum, Goat">Scrotum, Goat. The thin epidermis and a portion of a hair follicle are shown in detail. Epidermis Dermis, superficial layer Duct of sweat gland Hair follicle Hair follicle </entry>
<entry linktype="AI" linkname="EUR-012-029" title="Figure 12.29: Pinna (Auricle), External Ear, Dog">Pinna (Auricle), External Ear, Dog. A plate of elastic cartilage is covered by the skin of the outer (convex) and inner (concave) surfaces of the pinna. Hair follicles are more numerous in the skin of the outer surface. Elastic cartilage Hair follicle Epidermis, inner surface </entry>
<entry linktype="AI" linkname="EUR-012-030" title="Figure 12.30: Pinna, External Ear, Dog">Pinna, External Ear, Dog. Clusters of compound hair follicles cut in cross section vary in appearance at different levels of the dermis. The cells of the cortex and medulla of the hairs are evident in the deepest portions of the follicles. More superficially, the cells become keratinized and appear shiny pink (medulla) and yellow (cortex). Several hairs have merged to share a common follicle wall near the epidermis.</entry>
<entry linktype="AI" linkname="EUR-012-031" title="Figure 12.31: Pinna, External Ear, Dog">Pinna, External Ear, Dog. Detail of follicles, shown in cross section, from the deep region of the dermis, similar to those in Figure 12.30.</entry>
<entry linktype="AI" linkname="EUR-012-033" title="Figure 12.33: Sinus Hair Follicle, l.s., Nose, Cow">Sinus Hair Follicle, l.s., Nose, Cow. The entire length of the blood-filled sinus is crossed by numerous trabeculae in sinus hair follicles of ruminants, horses, and pigs. Sebaceous gland Epidermis Erythrocytes Connective tissue sheath, outer Hair bulb Connective tissue sheath, outer Connective tissue sheath, inner Hair Trabecula </entry>
<entry linktype="AI" linkname="EUR-012-034" title="Figure 12.34: Sinus Hair Follicle, Oblique Section, Nose, Dog">Sinus Hair Follicle, Oblique Section, Nose, Dog. The large sinus hair follicle contains a blood-filled sinus, lined by an endothelium, between the inner and outer layers of the connective tissue sheath. In carnivores only the lower region of the sinus is spanned by a network of trabeculae of connective tissue. The upper region contains an annular sinus, free of trabeculae, into which protrudes a thickening of the inner connective tissue sheath called the sinus pad. Epidermis Hair Sebaceous gland Outer root sheath Annular sinus Hair Sinus pad Trabecula Connective tissue sheath, outer Connective tissue sheath, inner Sinus pad Inner root sheath Annular sinus Sebaceous gland </entry>
<entry linktype="AI" linkname="EUR-012-035" title="Figure 12.35: Sinus Hair Follicle, Nose, Dog">Sinus Hair Follicle, Nose, Dog. Detail of Figure 12.34. Portion of the sinus pad, annular sinus, and trabeculated sinus. Note the Merkel's cells, associated with tactile stimulation, in the external (outer) root sheath. Annular sinus Erythrocytes Merkel’s cell 3 Outer root sheath Endothelial cell, nucleus Connective tissue sheath, outer Trabecula Connective tissue sheath, inner </entry>
<entry linktype="AI" linkname="EUR-012-036" title="Figure 12.36: Sebaceous Gland and Hair Follicle, l.s., Lip, Sheep">Sebaceous Gland and Hair Follicle, l.s., Lip, Sheep. The inner root sheath forms follicular (circular) folds below the entrance of sebaceous glands into the follicle.</entry>
<entry linktype="AI" linkname="EUR-012-037" title="Figure 12.37: Nose, Dog">Nose, Dog. Longitudinal sections of two serpentine sweat glands. Their tubular structure is evident. Duct Duct Hair follicle Sebaceous gland Sweat gland, l.s. Sweat gland, x.s. Sweat gland, l.s. </entry>
<entry linktype="AI" linkname="EUR-012-038" title="Figure 12.38: Sebaceous Gland and Sweat Gland, Nose, Dog">Sebaceous Gland and Sweat Gland, Nose, Dog. The secretory portion of a sweat gland, lined by cuboidal to columnar cells, is continuous with the bistratified, flattened cells of its duct. The cell types found in the holocrine sebaceous gland are evident: small, flat, peripheral stem cells; maturing, round cells with pale, vacuolated cytoplasm; inner degenerating cells with pyknotic nuclei. Duct Stem cell Sebaceous gland Pyknotic nucleus Stem cell Vacuolated cell Secretory portion, sweat gland Myoepithelial cell, nucleus </entry>
<entry linktype="AI" linkname="EUR-012-039" title="Figure 12.39: Sweat Gland, Skin, Horse (Trichrome)">Sweat Gland, Skin, Horse (Trichrome). Cross and oblique sections of a coiled sweat gland in the dermis are lined by cuboidal to columnar cells and surrounded by myoepithelial cells. The solid sheet of several cells represents a surface cut through the wall of the gland. Myoepithelial cell, nucleus Secretory portion, sweat gland Capillary Secretory portion, sweat gland Gland cells, surface cut Capillary </entry>
<entry linktype="AI" linkname="EUR-012-040" title="Figure 12.40: Sweat Gland and Duct, Teat, Sheep">Sweat Gland and Duct, Teat, Sheep. Low columnar secretory cells with apical blebs end abruptly where the duct epithelium begins. Both the secretory cells and the initial segment of the duct are surrounded by myoepithelial cells. The cytoplasm of the myoepithelial cells appears as a pink, sometimes rippled band. Hair Myoepithelial cell, nucleus Secretory portion, sweat gland Myoepithelial cell, nucleus Myoepithelial cell, nucleus Duct </entry>
<entry linktype="AI" linkname="EUR-012-041" title="Figure 12.41: Sweat Gland, Teat, Sheep">Sweat Gland, Teat, Sheep. The secretory cells of sweat glands vary from squamous to tall columnar. They are squamous in this preparation, but are columnar in Figure 12.40. Note that one of the secretory portions is cut tangentially, revealing the elongated shape of the myoepithelial cells. Myoepithelial cell, cytoplasm Myoepithelial cell, nucleus, x.s. Secretory cell, nucleus Secretory cell, nucleus Myoepithelial cell, nucleus, l.s. </entry>
<entry linktype="AI" linkname="EUR-012-042" title="Figure 12.42: Sweat Gland, Teat, Sheep (Silver and Eosin)">Sweat Gland, Teat, Sheep (Silver and Eosin). The basement membrane of a sweat gland is blackened with silver. Myoepithelial cells occur between the flattened secretory cells and the basement membrane. Basement membrane Myoepithelial cell, cytoplasm Basement membrane Myoepithelial cell, nucleus, x.s. Secretory cell, nucleus </entry>
<entry linktype="AI" linkname="EUR-012-043" title="Figure 12.43: Carpal Gland, Pig">Carpal Gland, Pig. Lobules of merocrine sweat glands occur in the subcutaneous tissue on the medial side of the carpus of the pig. Duct of sweat gland Epidermis Hair follicle Sweat gland Dermis Hair bulb </entry>
<entry linktype="AI" linkname="EUR-012-044" title="Figure 12.44: Carpal Gland, Pig">Carpal Gland, Pig. Dark and clear cells of the secretory units of these merocrine sweat glands are surrounded by myoepithelial cells. Dark cell Clear cell Clear cell Myoepithelial cell, nucleus, l.s. Dark cell </entry>
<entry linktype="AI" linkname="EUR-012-045" title="Figure 12.45: Infraorbital Pouch (Sinus), Sheep">Infraorbital Pouch (Sinus), Sheep. Many large sebaceous glands occupy the wall of the infraorbital pouch of sheep. Some apocrine sweat glands lie deep to the sebaceous glands. Hair follicle Sebaceous gland Duct of sweat gland Sweat gland Dermis Epidermis Sebaceous gland Sweat gland </entry>
<entry linktype="AI" linkname="EUR-012-046" title="Figure 12.46: Inguinal Pouch, Sheep">Inguinal Pouch, Sheep. The skin of the inguinal pouch of sheep contains a few hairs, sebaceous glands, and an abundance of apocrine sweat glands. Epidermis Sebaceous gland Hair follicle Sweat gland Sweat gland </entry>
<entry linktype="AI" linkname="EUR-012-047" title="Figure 12.47: Mammary Gland, Inactive, Cat">Mammary Gland, Inactive, Cat. Lobules of glandular tissue and ducts are surrounded by fibroelastic subcutaneous tissue. The overlying skin contains a few hairs. Large lymphatic vessels lie deep to the parenchyma. Epidermis Interlobular duct Gland Intralobular duct Lymphatic vessel </entry>
<entry linktype="AI" linkname="EUR-012-048" title="Figure 12.48: Mammary Gland, Inactive, Cow">Mammary Gland, Inactive, Cow. Abundant interlobular connective tissue and components of the duct system are evident in an inactive gland. Interlobular ducts branch into the lobules as intralobular ducts. Interlobular duct Intralobular duct Interlobular connective tissue Lobule Intralobular duct </entry>
<entry linktype="AI" linkname="EUR-012-049" title="Figure 12.49: Mammary Gland, Inactive, Cow">Mammary Gland, Inactive, Cow. Lobules are composed of intralobular ducts and intralobular connective tissue, which is moderately rich in cells. Thickenings at the terminations of intralobular ducts represent remnants or precursors of glandular epithelium. When these are cut in cross section, they cannot always be distinguished from ducts. Intralobular duct Intralobular connective tissue Glandular epithelium Interlobular connective tissue Glandular epithelium Intralobular connective tissue Intralobular duct </entry>
<entry linktype="AI" linkname="EUR-012-050" title="Figure 12.50: Mammary Gland, Active, Cow">Mammary Gland, Active, Cow. In the active gland, secretory parenchyma is well developed and connective tissue is reduced. Compare with Figure 12.48. The lumens of the secretory glands and ducts are filled with secretion <i>(deep pink)</i>. Corpora amylacea Lobule Secretory unit Intralobular duct Intralobular duct Interlobular duct Secretory unit Corpora amylacea </entry>
<entry linktype="AI" linkname="EUR-012-051" title="Figure 12.51: Mammary Gland, Active, Cow">Mammary Gland, Active, Cow. A portion of a lobule containing numerous tubuloacinar secretory units. Some of the alveoli contain round concretions of casein and cellular debris called corpora amylacea. Secretory unit Intralobular connective tissue Intralobular connective tissue Corpora amylacea </entry>
<entry linktype="AI" linkname="EUR-012-052" title="Figure 12.52: Mammary Gland, Active, Cow">Mammary Gland, Active, Cow. Many secretory cells have basally displaced nuclei and indistinct lateral cell borders. These cells appear pale because their cytoplasmic lipids have been extracted. Sloughed cells, whose dark nuclei are visible in the lumens, are part of the secretory product. Some of the flat nuclei surrounding the alveoli belong to myoepithelial cells. Intralobular connective tissue Secretory cell, nucleus Myoepithelial cell, nucleus Secretion </entry>
<entry linktype="AI" linkname="EUR-012-053" title="Figure 12.53: Teat, x.s., Dog">Teat, x.s., Dog. A portion of the teat shows numerous sinuses among intermingling bundles of smooth muscle and fibroelastic connective tissue. Nonruminants have multiple teat sinuses and teat canals. Some glands and hairs are associated with the skin of the teat of carnivores, horses, sheep, and goats. Teat sinus Smooth muscle Smooth muscle Sweat gland Epidermis </entry>
<entry linktype="AI" linkname="EUR-012-054" title="Figure 12.54: Teat Sinus, x.s., Dog">Teat Sinus, x.s., Dog. Detail of a teat sinus of Figure 12.53 reveals a highly folded lining. Glandular areas, composed of small secretory units, are associated with the wall of the sinus. Connective tissue Connective tissue Teat sinus Smooth muscle Secretory unit </entry>
<entry linktype="AI" linkname="EUR-012-055" title="Figure 12.55: Teat Sinus, x.s., Cat">Teat Sinus, x.s., Cat. This cross section through a teat reveals five teat sinuses. Some of these contain a secretion that is stained pink. Epidermis Teat sinus Teat sinus </entry>
<entry linktype="AI" linkname="EUR-012-056" title="Figure 12.56: Teat Sinus, x.s., Horse (Orcein)">Teat Sinus, x.s., Horse (Orcein). A band of collagenous fibers lies between the epithelium and the underlying fibroelastic connective tissue. Epithelium Collagenous band Elastic fibers </entry>
<entry linktype="AI" linkname="EUR-012-057" title="Figure 12.57: Teat Sinus, x.s., Cow">Teat Sinus, x.s., Cow. The mucosa of the teat sinus blends with the middle layer of the teat. The latter contains well-developed, longitudinally oriented blood vessels (cut in x.s.), bundles of smooth muscle, fibroelastic tissue, and lymphatic vessels. The outer layer, the skin surface, is not shown. Lymphatic vessel Teat sinus Smooth muscle Blood vessel </entry>
<entry linktype="AI" linkname="EUR-012-058" title="Figure 12.58: Teat Sinus, x.s., Cow">Teat Sinus, x.s., Cow. The teat sinus is lined by a bistratified cuboidal to columnar epithelium. Bistratified cuboidal epithelium Teat sinus Lamina propria Bistratified columnar epithelium </entry>
<entry linktype="AI" linkname="EUR-012-059" title="Figure 12.59: Teat Sinus, x.s., Sheep, Male">Teat Sinus, x.s., Sheep, Male. The skin of the teat contains hairs, sebaceous glands, and sweat glands, except in the cow and pig. Compare with Figure 12.63. Epidermis Hair follicle Sebaceous gland Hair follicle Sweat gland Teat sinus Blood vessel </entry>
<entry linktype="AI" linkname="EUR-012-060" title="Figure 12.60: Teat Sinus and Canal, Junction, x.s., Horse">Teat Sinus and Canal, Junction, x.s., Horse. Patches of the bistratified epithelium (columnar and cuboidal) of the teat sinus intermingle with the stratified squamous epithelium of the teat canal. Bistratified columnar epithelium Lamina propria Stratified squamous epithelium Lamina propria Bistratified cuboidal epithelium </entry>
<entry linktype="AI" linkname="EUR-012-061" title="Figure 12.61: Teat Canal, x.s., Cow (Trichrome)">Teat Canal, x.s., Cow (Trichrome). The keratinized stratified squamous lining of the teat canal is encircled by a papillated layer (green) of connective tissue and bundles of smooth muscle <i>(pale yellow)</i>. Smooth muscle Epithelium Blood vessel Smooth muscle Blood vessel </entry>
<entry linktype="AI" linkname="EUR-012-062" title="Figure 12.62: Teat Canal, x.s., Cow (Trichrome)">Teat Canal, x.s., Cow (Trichrome). Detail of the thick, keratinized, stratified squamous epithelium and the surrounding connective tissue and smooth muscle shown in Figure 12.61. Stratum corneum Stratum spinosum Stratum basale Smooth muscle </entry>
<entry linktype="AI" linkname="EUR-012-063" title="Figure 12.63: Skin Surface, Teat, x.s., Cow (Trichrome)">Skin Surface, Teat, x.s., Cow (Trichrome). The skin surface of the teat of the cow and pig is hairless. Epidermis Dermis Blood vessel </entry>
<entry linktype="AI" linkname="EUR-012-064" title="Figure 12.64: Developing Claw, l.s., Fetus, Dog">Developing Claw, l.s., Fetus, Dog. The claw of carnivores consists of a dorsal and lateral wall (body, claw plate) and a ventral sole of hard keratin that cover the distal phalanx. The claw fold is the skin that covers the wall at the base of the claw. Endochondral bone formation has begun in the phalanges of this specimen. Middle phalanx Claw fold Dermis Wall Sole Limiting furrow Distal phalanx Digital pad </entry>
<entry linktype="AI" linkname="EUR-012-065" title="Figure 12.65: Sole of Claw and Digital Pad, Dog">Sole of Claw and Digital Pad, Dog. The limiting furrow separates the digital pad from the sole of the claw. Epidermis, digital pad Dermis Merocrine sweat gland Distal phalanx Dermis Limiting furrow Sole </entry>
<entry linktype="AI" linkname="EUR-012-066" title="Figure 12.66: Apex of Claw, l.s., Dog">Apex of Claw, l.s., Dog. The dermis of the wall bears laminae (lamellae) at the apex of the claw. Distal phalanx Dermis Sole Laminae Wall </entry>
<entry linktype="AI" linkname="EUR-012-067" title="Figure 12.67: Horn, Cow">Horn, Cow. Horns of ruminants are composed of bone of the cornual process covered by a dermis and epidermis. The epidermis with a thick stratum corneum of hard keratin (horn) and a portion of the underlying papillated dermis are shown here. (Photograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Stratum corneum Stratum spinosum Dermis Stratum basale </entry>
<entry linktype="AI" linkname="EUR-012-068" title="Figure 12.68: Chestnut, Horse">Teat Sinus, x.s., Cow. The teat sinus is lined by a bistratified cuboidal to columnar epithelium. Bistratified cuboidal epithelium Teat sinus Lamina propria Bistratified columnar epithelium </entry>
<entry linktype="AI" linkname="EUR-012-069" title="Figure 12.69: Chestnut, Horse">Teat Sinus, x.s., Sheep, Male. The skin of the teat contains hairs, sebaceous glands, and sweat glands, except in the cow and pig. Compare with Figure 12.63. Epidermis Hair follicle Sebaceous gland Hair follicle Sweat gland Teat sinus Blood vessel </entry>
<entry linktype="AI" linkname="EUR-012-070" title="Figure 12.70: Chestnut, Horse">Chestnut, Horse. The section was cut parallel to the surface of the chestnut at the level of the stratum corneum. Horn tubules appear in cross section between intertubular horn. Horn tubule Intertubular horn Horn tubule </entry>
<entry linktype="AI" linkname="EUR-012-071" title="Figure 12.71: Hoof, Horse">Hoof, Horse. The various regions of the hoof are shown. The inner surface of the periople and coronary region and that of the sole, frog, and bulbs are stippled in the drawing. In the intact toe, dermal papillae extend into the funnel-shaped depressions whose openings are represented by the stipples. Epidermal laminae Periople Coronary region Sole Bar Bulb Frog Periople Coronary region White line </entry>
<entry linktype="AI" linkname="EUR-012-072" title="Figure 12.72: Sole, Hoof, Horse">Sole, Hoof, Horse. The sole forms most of the ventral surface of the hoof. It is bordered by the bars, the apex of the frog, and the inner border of the wall of the hoof. Laminae of wall Sole Frog Bar Bulb Stratum medium, deep unpigmented layer White line </entry>
<entry linktype="AI" linkname="EUR-012-073" title="Figure 12.73: Developing Hoof, l.s., Fetus, Horse">Developing Hoof, l.s., Fetus, Horse. The regions that form the three layers of the hoof wall are apparent: the perioplic, coronary, and laminar regions. Perioplic epidermis Perioplic dermis Hair follicle, developing Coronary epidermis Coronary dermis Cartilage, developing P3 Laminar dermis </entry>
<entry linktype="AI" linkname="EUR-012-074" title="Figure 12.74: Developing Hoof, Coronary Region, l.s., Fetus, Horse">Developing Hoof, Coronary Region, l.s., Fetus, Horse. Portion of coronary epidermis and coronary dermis, later in development than in Figure 12.73, showing tubular and intertubular horn. The medulla and cortex of the horn tubules are formed from the cells of the stratum basale that cover the tip and the sides of dermal papillae, respectively. Intertubular horn is formed by cells of the stratum basale that are located between the bases of the dermal papillae. (Photograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Horn tubule Intertubular horn Horn tubule Dermal papilla Coronary dermis </entry>
<entry linktype="AI" linkname="EUR-012-075" title="Figure 12.75: Developing H oof, Coronary R egion, l.s., Fetus, Horse">Developing Hoof, Coronary Region, l.s., Fetus, Horse. Detail of Figure 12.74, showing two horn tubules in longitudinal section. (Photograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Intertubular horn Horn tubule, cortex Horn tubule, medulla Horn tubule, cortex Intertubular horn Horn tubule, medulla </entry>
<entry linktype="AI" linkname="EUR-012-076" title="Figure 12.76: Hoof, Coronary Region, x.s., Horse">Hoof, Coronary Region, x.s., Horse. Dermal papillae and horn tubules of tubular horn. (Photograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Horn tubule Intertubular horn Horn tubule Dermal papilla Dermal papilla Coronary dermis </entry>
<entry linktype="AI" linkname="EUR-012-077" title="Figure 12.77: Developing Hoof, Wall and Sole, x.s., Fetus, Horse">Developing Hoof, Wall and Sole, x.s., Fetus, Horse. The dermis of the wall is laminated, while that of the sole is papillated. Dermis, wall Bone, P3 Dermis, sole Epidermis, wall Epidermis, sole </entry>
<entry linktype="AI" linkname="EUR-012-078" title="Figure 12.78: Developing Hoof, Wall, x.s., Fetus, Horse">Developing Hoof, Wall, x.s., Fetus, Horse. Detail of Figure 12.77. The epidermal laminae, at this time, consist mainly of a layer of basal cells (stratum basale). Primary epidermal laminae have begun to form secondary laminae. The primary and secondary dermal laminae are extensions of the laminar dermis. Stratum medium Epidermal lamina, primary Dermal lamina, primary Dermal lamina, secondary Epidermal lamina, primary Dermal lamina, secondary Dermal lamina, secondary Dermal lamina, primary Basal cell Epidermal lamina, secondary Laminar dermis Epidermal lamina, secondary Basal cell </entry>
<entry linktype="AI" linkname="EUR-012-079" title="Figure 12.79: Hoof, Laminar Region, x.s., Horse">Hoof, Laminar Region, x.s., Horse. Horn tubules of the stratum medium are seen in cross section. Primary and secondary epidermal laminae of the stratum internum interdigitate with the laminar dermis, which anchors the third phalanx to the wall of the hoof. Epidermal laminae, which are long ridges, appear featherlike in cross section. (Photograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Dermal lamina, secondary Epidermal lamina, primary Dermal lamina, primary Horn tubule Epidermal lamina, primary Dermal lamina, secondary Blood vessel Epidermal lamina, secondary Laminar dermis Epidermal lamina, secondary Bone, P3 </entry>
<entry linktype="AI" linkname="EUR-012-080" title="Figure 12.80: Hoof, Laminar Region, x.s., Horse">Hoof, Laminar Region, x.s., Horse. Primary epidermal laminae of the stratum internum, continuous with the stratum medium, bear secondary epidermal laminae. These interdigitate with primary and secondary dermal laminae. The secondary epidermal laminae and the dermal laminae comprise the sensitive laminae. Nuclei of the basal cells appear as small dark spots along the periphery of secondary epidermal laminae. (Photograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Horn tubule Horn tubule Epidermal lamina, secondary Dermal lamina, secondary Epidermal lamina, primary Dermal lamina, primary Epidermal lamina, secondary Dermal lamina, secondary Epidermal lamina, primary </entry>
<entry linktype="AI" linkname="EUR-012-081" title="Figure 12.81: Hoof, Sole, Oblique Section, Horse">Hoof, Sole, Oblique Section, Horse. Dermal papillae and horn tubules of the sole are shown. (Photograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Horn tubule Intertubular horn Horn tubule Dermal papilla </entry>
<entry linktype="AI" linkname="EUR-012-082" title="Figure 12.82: Skin, Neck, Chicken">Skin, Neck, Chicken. The epidermis of feathered skin is very thin and composed of a stratum germinativum and stratum corneum. The layers of the stratum germinativum are evident in Figure 12.92. Nuclei of the epidermal cells are often organized into stacks perpendicular to the surface. Abundant small blood vessels appear in the superficial region of the dermis. Dermis Stack of nuclei Stratum corneum Stratum germinativum </entry>
<entry linktype="AI" linkname="EUR-012-083" title="Figure 12.83: Feather Follicle, Skin, Neck, Chicken">Feather Follicle, Skin, Neck, Chicken. Oblique section through the basal region of a follicle with a developing feather. An epidermal collar surrounds the dermal papilla. The upper portion of the dermal papilla blends with the feather pulp. Dermis Feather muscle Feather follicle Feather pulp Corneous cells Dermal papilla Axial blood vessel Dermis Epidermal collar Feather muscle </entry>
<entry linktype="AI" linkname="EUR-012-085" title="Figure 12.85: Skin, Chicken">Skin, Chicken. Oblique section of a developing contour feather. Melanocytes lie among cells of the barb. Barbule cells, beginning with the outermost ones, receive pigment from the processes of the melanocytes. Feather sheath Feather pulp Melanocyte </entry>
<entry linktype="AI" linkname="EUR-012-086" title="Figure 12.86: Skin, Chicken">Skin, Chicken. Longitudinal section of a contour feather showing several developing barbs, later in development than in Figure 12.85. The pale, cuboidal cells at the base of each barb form the stem of the barb. Feather pulp Feather sheath Cells of barb stem Barbules Barbules Stratum corneum, follicle Stratum germinativum, follicle </entry>
<entry linktype="AI" linkname="EUR-012-087" title="Figure 12.87: Skin, Chicken">Skin, Chicken. Portion of contour feather follicle, x.s., at level of calamus (quill). Note that feather pulp has been replaced by an air space. Feather muscle Stratum corneum, follicle Stratum germinativum, follicle Air space Calamus (quill) </entry>
<entry linktype="AI" linkname="EUR-012-089" title="Figure 12.89: Skin, Eyelid, Chicken">Skin, Eyelid, Chicken. Feather follicles, x.s. The follicle wall of the tiny filoplume feather is relatively thick. A feather muscle attaches to the sheath of connective tissue of the follicle of a contour feather by an elastic tendon. Stratum corneum Stratum germinativum, skin Follicle, filoplume feather Calamus (quill) Elastic tendon Follicle, contour feather Feather muscle </entry>
<entry linktype="AI" linkname="EUR-012-090" title="Figure 12.90: Wattle, x.s., Rooster">Wattle, x.s., Rooster. Numerous sinus capillaries in the superficial layer of the dermis impart a red color to the wattle (and comb) when filled with blood. Mucous connective tissue of the intermediate layer of the dermis surrounds the central layer of dense connective tissue. Mucous connective tissue Epidermis Dermis, superficial layer Sinus capillary Mucous connective tissue Dermis, central layer Epidermis </entry>
<entry linktype="AI" linkname="EUR-012-091" title="Figure 12.91: Comb, Rooster">Comb, Rooster. The point of a comb is similar in appearance to the wattle (Figure 12.90). The collagenous fibers of the central layer of the dermis arise from the periosteum of the skull and carry vessels and nerves to the extremities of the comb. These vessels of the comb are shown in Figure 12.92. Sinus capillary Epidermis Dermis, superficial layer Mucous connective tissue Dermis, central layer Mucous connective tissue </entry>
<entry linktype="AI" linkname="EUR-012-092" title="Figure 12.92: Comb, Rooster">Comb, Rooster. Portion of epidermis and superficial dermis. The stratum corneum and layers of the stratum germinativum (basal, intermediate, and transitional layers) are evident. The lower ends of the cells of the basal layer bulge into the dermis, so that the epidermal-dermal boundary is uneven. Numerous anastomosing, blood-filled sinus capillaries in the superficial layer of the dermis are lined by pigment-laden endothelial cells. Endothelial cell, nucleus Sinus capillary Endothelial cell, nucleus Erythrocyte Basal layer Intermediate layer Sinus capillary Stratum corneum Transitional layer </entry>
<entry linktype="AI" linkname="EUR-012-093" title="Figure 12.93: Comb, Hen">Comb, Hen. The comb of a laying hen, compared with that of a rooster, contains less mucous connective tissue and more dense connective tissue in the intermediate layer, as well as fewer and smaller sinus capillaries in the superficial layer of the dermis (Figure 12.94). Sinus capillaries Dermis, intermediate layer Dermis, superficial layer Mucous connective tissue Epidermis Dermis, intermediate layer Dermis, central layer Adipose tissue Dermis, central layer </entry>
<entry linktype="AI" linkname="EUR-012-094" title="Figure 12.94: Comb, Hen">Comb, Hen. Detail of the epidermis and a portion of the dermis in Figure 12.93. Fewer and smaller sinus capillaries are in the superficial layer of the dermis of the comb of the laying hen as compared with that of the rooster. Note the arrangement of the nuclei of epidermal cells into stacks. Dermis, intermediate layer Herbst corpuscle Blood Vessel Adipose tissue Bone </entry>
<entry linktype="AI" linkname="EUR-012-095" title="Figure 12.95: Comb, Hen">Comb, Hen. Numerous Merkel's cells are located along the inner surface of the epidermis. These cells are associated with tactile nerve endings. Stratum corneum Merkel's cell Sinus capillary Merkel's cell Dermis, superficial layer Stratum germinativum </entry>
<entry linktype="AI" linkname="EUR-012-096" title="Figure 12.96: Upper Beak, x.s., Chicken">Upper Beak, x.s., Chicken. One side of the upper beak is shown. The bone of the premaxilla is covered by a periosteum, dermis, and epidermis with a thick layer of hard keratin. The dermis of the lateral surface of the upper beak often contains Herbst corpuscles; one corpuscle is shown here. See Figure 9.35 for detail of this corpuscle. Dermal papillae of the lateral surface diminish medially. The lower beak slips inside the upper beak between the palatine ridge and the stratum corneum of the medial surface. Palatine ridge Oral cavity Stratum germinativum Stratum corneum Bone Dermal papilla Herbst corpuscle Stratum corneum Periosteum Tomial edge </entry>
<entry linktype="AI" linkname="EUR-012-097" title="Figure 12.97: Upper Beak, x.s., Chicken">Upper Beak, x.s., Chicken. Detail of dermis and epidermis of the tomial edge of Figure 12.96. Cells of the stratum basale vary in height and width, so that intermittent groups of tall, slender cells form epidermal pegs between which project dermal papillae. Blood Vessel Epidermal peg Dermal papilla Stratum germinativum Stratum corneum Oral cavity </entry>
<entry linktype="AI" linkname="EUR-012-098" title="Figure 12.98: Spur, Hen">Spur, Hen. The spur cap consists of an extremely thick stratum corneum of hard keratin. Stratum corneum Stratum germinativum Dermis Adipose tissue, subcutis </entry>
<entry linktype="AI" linkname="EUR-012-099" title="Figure 12.99: Scutes, l.s., Anterior Metatarsus, Chicken">Scutes, l.s., Anterior Metatarsus, Chicken. Scutes are large scales that are covered by hard keratin. Their region of overlap, shown here, forms a sulcus lined by soft keratin. Keratin, hard Keratin, soft Sulcus Dermis Adipose tissue, subcutis </entry>
<entry linktype="AI" linkname="EUR-012-100" title="Figure 12.100: Scutes, l.s., Anterior Metatarsus, Chicken">Scutes, l.s., Anterior Metatarsus, Chicken. The region of overlap of two scutes shows the transition from the hard keratin to the deeper-staining, soft keratin of the sulcus. Keratin, hard Stratum germinativum Dermis Keratin, soft Sulcus </entry>
<entry linktype="AI" linkname="EUR-012-101" title="Figure 12.101: Reticulate Scale, x.s., Digit, Chicken">Reticulate Scale, x.s., Digit, Chicken. The hard keratin of the stratum corneum covers the outer surface and lines the sulci of these small scales from the lateral metatarsus. Sulcus Dermis Stratum corneum Stratum germinativum </entry>
<entry linktype="AI" linkname="EUR-012-102" title="Figure 12.102: Digital Pad, Chicken">Digital Pad, Chicken. A thick keratinized epithelium, a dermis, and a thick cushion of adipose tissue in the subcutis characterize the digital pad. Stratum corneum Dermis Adipose tissue, subcutis Stratum germinativum </entry>
<entry linktype="AI" linkname="EUR-012-103" title="Figure 12.103: Multilocular Fat, Digital Pad, Chicken">Multilocular Fat, Digital Pad, Chicken. Multilocular adipocytes, containing numerous lipid vacuoles and a central nucleus, are common in the subcutis of the chicken. Multilocular fat cell, nucleus </entry>
<entry linktype="AI" linkname="EUR-012-104" title="Figure 12.104: Claw, l.s., Chicken">Claw, l.s., Chicken. The dotted line indicates the approximate location of the drawing (cross section) of the claw shown in Figure 12.105. Footpad </entry>
<entry linktype="AI" linkname="EUR-012-105" title="Figure 12.105: Claw, Base, x.s., Chicken">Claw, Base, x.s., Chicken. The region of the base of the claw indicated with a dotted line in Figure 12.104 is represented in cross section in this drawing. Bone, distal phalanx Tendon Dermis Stratum germinativum Unguinal scale, dorsal surface Unguinal scale, ventral surface Dorsal plate, claw </entry>
<entry linktype="AI" linkname="EUR-012-106" title="Figure 12.106: Claw, Base, x.s., Chicken">Claw, Base, x.s., Chicken. Compare this photomicrograph with Figures 12.104 and 12.105. The free edge of the dorsal, unguinal scale (scute type) overlaps the base of the claw, so that a cross section reveals a dorsal and ventral surface of the scale. The soft keratin of the ventral surface of the scale abuts the dorsal plate of hard keratin of the base of the claw. The dorsal plate curves ventrally over the bone of the distal phalanx. Bone, distal phalanx Bone, distal phalanx Dorsal plate, claw Dermis Dermis Stratum germinativum Unguinal scale, ventral surface Unguinal scale, dorsal surface </entry>
<entry linktype="AI" linkname="EUR-012-107" title="Figure 12.107: Uropygial Gland, l.s., Chicken">Uropygial Gland, l.s., Chicken. A portion of one lobe of this bilobed holocrine gland shows branched tubular glands surrounded by a capsule of connective tissue. Each tubular gland is composed of a peripheral, sebaceous zone and an inner, glycogen zone. The latter communicates with the lumen of the lobe. Lobe, lumen Glycogen zone Sebaceous zone Capsule of connective tissue </entry>
<entry linktype="AI" linkname="EUR-012-108" title="Figure 12.108: Uropygial Gland, l.s., Chicken">Uropygial Gland, l.s., Chicken. The lumen of a lobe communicates with a primary duct, which passes through the isthmus toward the papilla of the gland. Sebaceous zone Glycogen zone Glycogen zone Isthmus Primary duct Lobe, lumen Epidermis </entry>
<entry linktype="AI" linkname="EUR-012-109" title="Figure 12.109: Uropygial Gland, l.s., Chicken">Uropygial Gland, l.s., Chicken. The two primary ducts pass through the papilla (nipple). Their openings (not shown) onto the surface are surrounded by feathers. Adipose tissue Primary duct Smooth muscle Primary duct Epidermis Smooth muscle Feather follicle </entry>
<entry linktype="AI" linkname="EUR-012-110" title="Figure 12.110: Sebaceous Zone, Uropygial Gland, Chicken">Sebaceous Zone, Uropygial Gland, Chicken. Portions of tubular glands are shown in cross section. The basal layer of the glandular epithelium is represented by the oval to flat nuclei of the small basal cells. A single layer of acidophilic and grainy intermediate cells lies on the basal layer. Cells of the thick, central (transitional) layer accumulate lipid, hypertrophy, and degenerate toward the luminal surface. Gland, lumen Intermediate cell Basal cell, nucleus Basal cell, nucleus Intermediate cell Basal cell, nucleus Central layer </entry>
<entry linktype="AI" linkname="EUR-012-111" title="Figure 12.111: Glycogen Zone, Uropygial Gland, Chicken">Glycogen Zone, Uropygial Gland, Chicken. Portions of tubular glands are shown in cross section. Intermediate cells, with an acidophilic and grainy cytoplasm, form a thick layer in the glycogen zone. The pale cells of the central layer are less numerous. Compare with Figure 12.110. Gland, lumen Intermediate cell Basal cell, nucleus Central layer </entry>
<entry linktype="AI" linkname="EUR-013-001" title="Figure 13.1: Lip, Sheep">The section was taken through the junction of the hairy and nonhairy portions of the lip. The stratum granulosum is present in the epidermis of the hairy portion of the lip, but disappears at the junction with the nonhairy portion of the lip. Portions of hair follicles are present. Connective tissue, papilla of Stratified squamous epithelium, keratinized Stratum granulosum Skeletal muscle Sebaceous gland Hair follicle </entry>
<entry linktype="AI" linkname="EUR-013-002" title="Figure 13.2: Lip, Sheep">Lip, Sheep. Oral surface of the lip with mixed labial glands among the skeletal muscle. Labial gland Stratified squamous epithelium, keratinized Skeletal muscle Duct Labial gland </entry>
<entry linktype="AI" linkname="EUR-013-004" title="Figure 13.4: Cheek, Sheep">Cheek, Sheep. The mucous membrane of the cheek of ruminants is characterized by numerous, conical papillae. The apex and lateral surfaces of the papillae are highly keratinized. Stratified squamous epithelium, keratinized Duct </entry>
<entry linktype="AI" linkname="EUR-013-005" title="Figure 13.5: Developing Permanent Tooth, Dog">Developing Permanent Tooth, Dog. The ectodermally derived enamel organ has differentiated into the outer and inner enamel epithelium and the stellate reticulum. The dental papilla, derived from mesenchyme, is in contact with the inner enamel epithelium. Alveolar bone Dental papilla Inner enamel epithelium Stellate reticulum Outer enamel epithelium Dental lamina Dental sac </entry>
<entry linktype="AI" linkname="EUR-013-006" title="Figure 13.6: Developing Permanent Tooth, Dog">Developing Permanent Tooth, Dog. Dentin and enamel formation has begun (Figure 13.7). Alveolar bone Dental sac Space artifact Dental papilla Odontoblasts Dentin Stellate reticulum Outer enamel epithelium Ameloblasts </entry>
<entry linktype="AI" linkname="EUR-013-007" title="Figure 13.7: Dentinoenamel Junction, Developing Permanent Tooth, Dog">Dentinoenamel Junction, Developing Permanent Tooth, Dog. Odontoblasts cover the surface of the mesenchymal dental papilla. These cells produce predentin (uncalcified dentin). The pale layer of predentin abuts the recently calcified dentin. The enamel organ consists of tall, columnar ameloblasts that produce enamel; a stratum intermedium; and the stellate reticulum. Space artifact Odontoblasts Dental papilla Dentin Predentin Enamel Stellate reticulum Stratum intermedium Ameloblasts </entry>
<entry linktype="AI" linkname="EUR-013-008" title="Figure 13.8: Root of Tooth, x.s., and Periodontal Ligament, Dog">Root of Tooth, x.s., and Periodontal Ligament, Dog. The periodontal ligament consists of bundles of collagenous fibers, blood and lymphatic vessels, nerves, and cells (mostly fibroblasts). The fiber bundles extend between, and anchor to, the cementum of the tooth and the alveolar bone. The ends of the fibers that are embedded in either cementum or bone are called Sharpey's fibers. They are indistinct in this micrograph. Dentin Cementum Precementum Alveolar bone Blood vessel Fiber bundle </entry>
<entry linktype="AI" linkname="EUR-013-009" title="Figure 13.9: Upper Deciduous Tooth, Decalcified, and Gingiva, l.s., Dog">Upper Deciduous Tooth, Decalcified, and Gingiva, l.s., Dog. The enamel space identifies the location of enamel before it was lost during decalcification. The attachment (junctional) epithelium of the gingiva is nonkeratinized stratified squamous and lacks papillae of connective tissue. It abuts the enamel region and is continuous with the papillated, keratinized stratified squamous epithelium of the free gingiva. Attachment epithelium Lamina propria Epithelium, free gingiva Enamel space Dentin Odontoblasts Dental pulp </entry>
<entry linktype="AI" linkname="EUR-013-010" title="Figure 13.10: Dental Pad, Cow">Dental Pad, Cow. The dental pad of ruminants is distinguished by its thick stratum corneum and well-developed papillae of connective tissue. Horn tubule-like structure </entry>
<entry linktype="AI" linkname="EUR-013-011" title="Figure 13.11: Epithelium, Dental Pad, Sheep">Epithelium, Dental Pad, Sheep. The section shows a thick stratum corneum and underlying stratum spinosum. A horn, a tubulelike structure, extends through the stratum corneum. Stratum corneum Stratum spinosum Stratum basale Connective tissue, papilla of Stratum spinosum Horn tubule-like structure </entry>
<entry linktype="AI" linkname="EUR-013-012" title="Figure 13.12: Hard Palate, Caudal, Dog (Masson's)">Hard Palate, Caudal, Dog (Masson's). All domestic mammals, except the pig, have glands (mucous or mixed) in the submucosa of the caudal portion of the hard palate. The cranial portion lacks glands in all of the domestic mammals. Stratified squamous epithelium, keratinized Mixed gland Palatine bone Palatine bone </entry>
<entry linktype="AI" linkname="EUR-013-013" title="Figure 13.13: Hard Palate, Pig">Hard Palate, Pig. Large irregular patches of pale, loose connective tissue are scattered throughout the submucosa. Stratified squamous epithelium, keratinized Connective tissue, papilla of Loose connective tissue </entry>
<entry linktype="AI" linkname="EUR-013-014" title="Figure 13.14: Soft Palate, Cow">Soft Palate, Cow. Mucous glands and adipose tissue occupy portions of the lamina propria and submucosa. The epithelium is stratified squamous and keratinized. Stratified squamous epithelium, keratinized Lamina propria Adipose tissue Mucous gland </entry>
<entry linktype="AI" linkname="EUR-013-015" title="Figure 13.15: Filiform Papilla, Tongue, Cat">Filiform Papilla, Tongue, Cat. The filiform papilla of carnivores contains several small, rostral connective tissue papillae and a large, caudal connective tissue papilla. A large, keratinized spine is associated with the caudal papilla. Spine Connective tissue, papilla of (caudal) Connective tissue, papilla of (rostral) Skeletal muscle </entry>
<entry linktype="AI" linkname="EUR-013-016" title="Figure 13.16: Filiform Papillae, Tongue, Horse">Filiform Papillae, Tongue, Horse. In horses and pigs, delicate, threadlike, keratinized projections extend from the upper surfaces of the filiform papillae. The papillae of connective tissue are long, but are not subdivided. Filiform papilla, projection of Filiform papilla, projection of Connective tissue, papilla of </entry>
<entry linktype="AI" linkname="EUR-013-017" title="Figure 13.17: Fungiform and Filiform Papillae, Tongue, Goat">Fungiform and Filiform Papillae, Tongue, Goat. This section is from the tip of the tongue. The fungiform papilla is moundlike in section with a broad core of connective tissue containing numerous nerves. Portions of keratinized projections of filiform papillae appear on either side. In ruminants, the connective tissue of filiform papillae is subdivided into several small papillae. Filiform papilla, projection of Fungiform papilla, core Filiform papilla, projection of Small papilla Skeletal muscle </entry>
<entry linktype="AI" linkname="EUR-013-018" title="Figure 13.18: Taste Bud, Fungiform Papilla, Tongue, Horse">Taste Bud, Fungiform Papilla, Tongue, Horse. The taste bud is embedded within the keratinized stratified squamous epithelium of a fungiform papilla. Supportive and sensory cells are visible within the bud. The nucleus and cytoplasm of the sensory cells are slightly darker than those of the supporting cells. Stratum spinosum </entry>
<entry linktype="AI" linkname="EUR-013-019" title="Figure 13.19: Circumvallate Papilla, Tongue, Goat">Circumvallate Papilla, Tongue, Goat. This large papilla lies within a depression of the lingual epithelium. Taste buds occur within the epithelium of the papilla facing the cavity of the depression, but are usually absent from the upper surface of the papilla. Stratified squamous epithelium Stratified squamous epithelium Connective tissue, core of Taste buds Lingual salivary gland Connective tissue, papilla of Duct Lingual salivary gland </entry>
<entry linktype="AI" linkname="EUR-013-020" title="Figure 13.20: Conical Papilla, Tongue, Goat">Conical Papilla, Tongue, Goat. This highly keratinized papilla is located on the upper surface of the tongue. Skeletal muscle Core of connective tissue Stratified squamous epithelium, keratinized </entry>
<entry linktype="AI" linkname="EUR-013-021" title="Figure 13.21: Lingual Salivary Glands, Horse">Lingual Salivary Glands, Horse. Both mucous and serous glands occur between the skeletal muscle bundles of the tongue. 3 Serous gland Mucous gland Adipose tissue Adipose tissue </entry>
<entry linktype="AI" linkname="EUR-013-022" title="Figure 13.22: Musculature, Tongue, l.s., Cat">Musculature, Tongue, l.s., Cat. The vertical, horizontal, and transverse arrangement of the lingual skeletal musculature can be seen below the mucosal papillae. Muscle, vertical Muscle, transverse Muscle, longitudinal Filiform papilla, epithelium of Muscle, vertical Muscle, transverse </entry>
<entry linktype="AI" linkname="EUR-013-023" title="Figure 13.23: Parotid Gland, Horse">Parotid Gland, Horse. Portions of several lobules are shown. Lobules are often delineated by space artifacts. See Figure 13.24 for detail of a lobule. Space artifact Interlobular connective tissue Interlobular duct Intralobular duct Lobule Intralobular duct Interlobular duct </entry>
<entry linktype="AI" linkname="EUR-013-024" title="Figure 13.24: Parotid Gland, Horse">Parotid Gland, Horse. Serous acini, intercalated ducts, and striated (secretory) ducts are present. The latter show clearly defined basal striations. Serous acinus Intercalated duct Serous acinus Basal striations Striated duct </entry>
<entry linktype="AI" linkname="EUR-013-026" title="Figure 13.26: Parotid Gland, Cow">Parotid Gland, Cow. The secretory units are lined by pale, acidophilic cells with large nuclei. The cells vary in height, giving the luminal surface a scalloped appearance. This feature is unique to the cow. Secretory unit Interlobular connective tissue Secretory unit </entry>
<entry linktype="AI" linkname="EUR-013-029" title="Figure 13.29: Submandibular Gland, Sheep (Mallory's)">Submandibular Gland, Sheep (Mallory's). The junction between a mucous acinus and an intercalated duct is illustrated. Serous demilune Mucous acinus Interlobular connective tissue Intercalated duct </entry>
<entry linktype="AI" linkname="EUR-013-030" title="Figure 13.30: Sublingual Gland, Dog">Sublingual Gland, Dog. In the cat, dog, and horse, the sublingual gland contains mucous secretory units, serous acini, and serous demilunes. Long tubular mucous units are a characteristic feature of the gland in the dog. Tubular mucous unit Serous demilune Serous acinus Interlobular connective tissue Striated duct Interlobular connective tissue Tubular mucous unit Serous acinus </entry>
<entry linktype="AI" linkname="EUR-013-031" title="Figure 13.31: Sublingual Gland, Pig">Sublingual Gland, Pig. In the pig and ruminant, mucous tubuloacinar secretory units predominate. Serous demilunes are sparse. Intercalated duct Intercalated duct Mucous acinus Serous demilune Interlobular connective tissue Striated duct </entry>
<entry linktype="AI" linkname="EUR-013-032" title="Figure 13.32: Interlobular Duct, Sublingual Gland, Pig">Interlobular Duct, Sublingual Gland, Pig. This large interlobular duct is lined by a columnar epithelium. The latter is bistratified in places. Goblet cells occur in the epithelium. Coat of connective tissue Goblet cells Blood vessel Blood vessel Epithelium Adipose tissue </entry>
<entry linktype="AI" linkname="EUR-013-033" title="Figure 13.33: Oropharynx, Dog">Oropharynx, Dog. The section shows mixed glands among the skeletal muscle and within the submucosa. Mixed glands are shown in detail in Figure 11.10. Skeletal muscle Skeletal muscle Mixed glands Duct Duct Stratified squamous epithelium </entry>
<entry linktype="AI" linkname="EUR-013-034" title="Figure 13.34: Oropharynx, Dog (Orcein)">Oropharynx, Dog (Orcein). A thick band of connective tissue, containing numerous elastic fibers, parallels the mucosa. Stratified squamous epithelium Lamina propria Elastic fibers Mixed glands </entry>
<entry linktype="AI" linkname="EUR-013-035" title="Figure 13.35: Esophagus, Mid-region, x.s., Dog">Esophagus, Mid-region, x.s., Dog. The glands of the dogÕs esophagus are predominantly mucous. They are located in the submucosa throughout the length of the esophagus of the dog. The muscularis externa is skeletal muscle, except very near the stomach (Figure 13.36). Duct Muscularis mucosae Blood vessel Mucous glands Muscularis externa, inner circular Muscularis externa, outer longitudinal Stratified squamous epithelium Lamina propria Submucosa </entry>
<entry linktype="AI" linkname="EUR-013-036" title="Figure 13.36: Esophagus, Near Stomach, l.s., Dog">Esophagus, Near Stomach, l.s., Dog. The muscularis externa of the dog's esophagus is composed of skeletal muscle, except in the region caudal to the diaphragm, where the musculature is mixed. Smooth muscle Muscularis externa, inner circular Muscularis externa, outer longitudinal Skeletal muscle Smooth muscle Smooth muscle Skeletal muscle </entry>
<entry linktype="AI" linkname="EUR-013-037" title="Figure 13.37: Esophagus, Cranial, l.s., Cat">Esophagus, Cranial, l.s., Cat. A few mixed glands are present in the submucosa. In the cat, horse, and ruminant, esophageal glands occur only near the junction of the esophagus and pharynx. The stratified squamous lining of the esophagus of carnivores is typically nonkeratinized. In the cat and hors, the muscularis externa is skeletal muscle throughout much of the esophagus. The transition from skeletal to smooth occurs in the caudal one-fifth to one-third of the esophagus in these animals. Adipose tissue Mixed glands Muscularis externa, inner circular Submucosa Lamina propria Stratified squamous epithelium </entry>
<entry linktype="AI" linkname="EUR-013-038" title="Figure 13.38: Esophagus, Cranial, x.s., Horse">Esophagus, Cranial, x.s., Horse. The papillated stratified squamous epithelium shows a distinct keratinized layer. The epithelium is also keratinized in pigs and ruminants. A sparse muscularis mucosae is present in the cranial esophagus in the horse, cat, and ruminant. The muscularis externa consists of skeletal muscle in this region. Stratified squamous epithelium, keratinized Lamina propria Muscularis mucosae Muscularis mucosae Submucosa Muscularis externa, inner circular </entry>
<entry linktype="AI" linkname="EUR-013-039" title="Figure 13.39: Esophagus, Cranial, l.s., Pig">Esophagus, Cranial, l.s., Pig. The stratified squamous epithelium is also keratinized in horses and ruminants. Note the abundance of mucous glands in the submucosa. In the cranial portion of the esophagus, a muscularis mucosae is absent in the pig and dog. The muscularis externa consists of skeletal muscle in this region. Stratified squamous epithelium, keratinized Esophagus, lumen Duct Lamina propria Mucous glands Mucous glands Submucosa Adipose tissue Muscularis externa, inner circular Muscularis externa, outer oblique Adventitia </entry>
<entry linktype="AI" linkname="EUR-013-040" title="Figure 13.40: Esophagus, Mid-region, l.s., Pig">Esophagus, Mid-region, l.s., Pig. Note the decrease in glandular tissue and the presence of a muscularis mucosae. Compare with Figure 13.39. The muscularis externa consists of skeletal muscle in this region. Stratified squamous epithelium Esophagus, lumen Submucosa Lamina propria Muscularis mucosae Muscularis externa, inner circular Mucous gland Muscularis externa, outer Adipose tissue Adventitia oblique </entry>
<entry linktype="AI" linkname="EUR-013-041" title="Figure 13.41: Esophagus, Caudal, x.s., Pig">Esophagus, Caudal, x.s., Pig. The region of the pig's esophagus just cranial to the diaphragm shows the presence of smooth and skeletal muscle in the muscularis externa, a lack of glands, and a thick muscularis mucosae. Esophagus, lumen Stratified squamous epithelium Muscularis mucosae Submucosa Lamina propria Muscularis externa, inner circular Serosa Muscularis externa, outer longitudinal </entry>
<entry linktype="AI" linkname="EUR-013-042" title="Figure 13.42: Esophagus, Caudal, x.s., Pig">Esophagus, Caudal, x.s., Pig. Detail of Figure 13.41 shows the smooth and skeletal musculature of the muscularis externa. Muscularis externa, inner circular Smooth muscle Skeletal muscle Smooth muscle Skeletal muscle Muscularis externa, outer longitudinal </entry>
<entry linktype="AI" linkname="EUR-013-043" title="Figure 13.43: Esophagus, Mid-Region, x.s., Sheep">Esophagus, Mid-Region, x.s., Sheep. The muscularis mucosae is less developed than in the pig (see Figure 13.40). Esophagus, lumen Stratified squamous epithelium Connective tissue, papilla of Lamina propria Connective tissue, papilla of Lamina propria Muscularis mucosae Submucosa Muscularis mucosae </entry>
<entry linktype="AI" linkname="EUR-013-044" title="Figure 13.44: Rumen, Sheep">Rumen, Sheep. The mucosa of the rumen is differentiated into paddle-shaped papillae.</entry>
<entry linktype="AI" linkname="EUR-013-045" title="Figure 13.45: Rumen, Cow">Rumen, Cow. A part of the wall from the lumen to the beginning of the muscularis externa (smooth muscle). A complete short papilla and a portion of a long papilla are included. Note the submucosa entering the long papilla. A muscularis mucosae is not present in this part of the forestomach. Submucosa Muscularis externa Lamina propria Stomach contents Stratified squamous epithelium, keratinized Submucosa </entry>
<entry linktype="AI" linkname="EUR-013-046" title="Figure 13.46: Rumen, Sheep">Rumen, Sheep. Section shows two cuts through adjacent long papillae. These papillae are flat, paddlelike, structures (Figure 13.44). The bottom one in the photograph was cut parallel to the flat surface, and the top one was cut perpendicular to the flat surface. A dense, more darkly stained band of connective tissue mimics a muscularis mucosae. Stratified squamous epithelium, keratinized Stratified squamous epithelium, keratinized Connective tissue, band of Submucosa Lamina propria </entry>
<entry linktype="AI" linkname="EUR-013-047" title="Figure 13.47: Rumen, Sheep">Rumen, Sheep. Section illustrates the vacuolated, keratinized cells of the stratified squamous epithelium of a papilla. Numerous capillaries abut the epithelium. Keratinized cells Stratified squamous epithelium, keratinized Capillary Lymphatic vessel Arteriole </entry>
<entry linktype="AI" linkname="EUR-013-048" title="Figure 13.48: Reticulum, Sheep">Reticulum, Sheep. The mucosa of the reticulum is extended into intersecting folds that subdivide the surface into distinct compartments, suggesting a honeycomb. Conical papillae project from the crests of the folds and from the mucosa of the compartments.</entry>
<entry linktype="AI" linkname="EUR-013-049" title="Figure 13.49: Reticulum, Cow">Reticulum, Cow. Short folds and the base of a long fold are visible. A muscularis mucosae occurs in the upper segment of the long fold. This is a characteristic feature of the reticulum. Sides and crests of long folds have conical papillae with keratinized tips. Conical papilla Conical papilla na na na Muscularis externa </entry>
<entry linktype="AI" linkname="EUR-013-050" title="Figure 13.50: Reticulum, Sheep">Reticulum, Sheep. Section shows a long fold cut in a plane parallel to its flat surface. The apparent gaps are the result of undulations in the fold. Conical papillae are evident along the crest of the fold. Stratified squamous epithelium, keratinized Conical papilla Muscularis mucosae Conical papilla Muscularis mucosae Submucosa Muscularis externa </entry>
<entry linktype="AI" linkname="EUR-013-051" title="Figure 13.51: Reticulum, Goat (Masson's)">Reticulum, Goat (Masson's). The section is through the region of intersection of three long folds. The muscularis mucosae passes from one fold to another at the intersection. Two conical papillae, with keratinized tips, project from the sides of two of the folds. Conical papilla Lamina propria Muscularis mucosae Stratified squamous epithelium, keratinized Muscularis mucosae </entry>
<entry linktype="AI" linkname="EUR-013-052" title="Figure 13.52: Omasum, Sheep">Omasum, Sheep. Laminae (folds) of different sizes extend from the wall of the omasum, somewhat like the pages of a book. The mucosal surfaces of the laminae are studded with numerous conical papillae.</entry>
<entry linktype="AI" linkname="EUR-013-053" title="Figure 13.53: Omasum, Sheep">Omasum, Sheep. Small folds such as the one shown contain a lamina propria and muscularis mucosae, but lack an extension of smooth muscle from the muscularis externa. Stratified squamous epithelium, keratinized Muscularis mucosae Lamina propria Lamina propria Muscularis externa Submucosa Muscularis mucosae </entry>
<entry linktype="AI" linkname="EUR-013-054" title="Figure 13.54: Omasum, Sheep">Omasum, Sheep. The base of a long fold is shown. In addition to the muscularis mucosae, smooth muscle from the muscularis externa projects into the center of the fold. Lamina propria Stratified squamous epithelium, keratinized Cardiac glands Smooth muscle of muscularis externa Cardiac glands Smooth muscle of muscularis externa </entry>
<entry linktype="AI" linkname="EUR-013-055" title="Figure 13.55: Omasum, Sheep">Omasum, Sheep. Portions of two long folds are shown. Numerous small papillae cover the surface of the folds. Cardiac glands Cardiac glands Smooth muscle of muscularis externa Cardiac glands Cardiac glands Lymphatic vessel Lamina propria Smooth muscle of muscularis externa Papilla Lymphatic vessel </entry>
<entry linktype="AI" linkname="EUR-013-056" title="Figure 13.56: Omasum, Goat (Orcein)">Omasum, Goat (Orcein). The lamina propria of a portion of a small papilla contains an extensive network of elastic fibers. Stratified squamous epithelium, keratinized Elastic fiber Elastic fiber Vein </entry>
<entry linktype="AI" linkname="EUR-013-057" title="Figure 13.57: Junction, Esophagus and Cardiac Gland Region of Stomach, Dog">Junction, Esophagus and Cardiac Gland Region of Stomach, Dog. Numerous glands, predominantly mucous with a few serous demilunes, occupy the submucosa of the esophagus and extend into the cardiac gland region of the stomach of dogs. Stratified squamous epithelium, esophagus Cardiac gland region Cardiac gland region Fundic gland region </entry>
<entry linktype="AI" linkname="EUR-013-058" title="Figure 13.58: Junction, Esophagus and Cardiac Gland Region of Stomach, Dog">Junction, Esophagus and Cardiac Gland Region of Stomach, Dog. Detail of Figure 13.57. The stratified squamous epithelium of the esophagus ends abruptly where the columnar epithelium of the stomach begins. Stratified squamous epithelium, esophagus Lamina propria Cardiac glands Columnar epithelium, stomach Lamina propria Cardiac glands </entry>
<entry linktype="AI" linkname="EUR-013-059" title="Figure 13.59: Junction of Esophagus and Stomach, Dog">Junction of Esophagus and Stomach, Dog. Section passes through the cardiac sphincter. Esophageal glands Cardiac sphincter Fundic gland region </entry>
<entry linktype="AI" linkname="EUR-013-060" title="Figure 13.60: Margo Plicatus, Horse">Margo Plicatus, Horse. At the margo plicatus, the keratinized stratified squamous epithelium of the forestomach ends, and the simple columnar epithelium of the cardiac gland region of the stomach begins. Stratified squamous epithelium, keratinized Simple columnar epithelium Cardiac glands Gastric pit Gastric pit Cardiac glands Connective tissue, papilla of Muscularis mucosae Fundic glands </entry>
<entry linktype="AI" linkname="EUR-013-061" title="Figure 13.61: Cardiac Gland Region, Stomach, Pig">Cardiac Gland Region, Stomach, Pig. Numerous lymphatic nodules characterize the mucosa of the cardiac gland region of the pig's stomach. Muscularis mucosae Cardiac glands Muscularis mucosae Gastric pit Lymphatic nodule </entry>
<entry linktype="AI" linkname="EUR-013-062" title="Figure 13.62: Light Zone, Fundic Gland Region, Stomach, Dog">Light Zone, Fundic Gland Region, Stomach, Dog. The light zone of the carnivore's fundic stomach has a thinner mucosa than the more aboral dark zone. The gastric pits of the light zone are comparatively deep, extending, in some cases, to a depth equivalent to half the thickness of the mucosa. Compare with Figure 13.65. Note that smooth muscle (arrows) of the muscularis mucosae of the stomach extends into the lamina propria. Simple columnar epithelium Gastric pit Muscularis mucosae Submucosa Fundic glands Lamina propria Muscularis mucosae </entry>
<entry linktype="AI" linkname="EUR-013-063" title="Figure 13.63: Light Zone, Fundic Gland Region, Stomach, Dog">Light Zone, Fundic Gland Region, Stomach, Dog. Chief and parietal cells form the walls of the fundic glands. The glands are shown in cross section. Parietal cell Lamina propria Parietal cell Chief cell Chief cell Lamina propria </entry>
<entry linktype="AI" linkname="EUR-013-064" title="Figure 13.64: Dark Zone, Fundic Gland Region, Stomach, Dog">Dark Zone, Fundic Gland Region, Stomach, Dog. A portion of the stomach wall, including the base of a fold, is shown. Mucosa Submucosa Submucosa Muscularis externa Serosa </entry>
<entry linktype="AI" linkname="EUR-013-065" title="Figure 13.65: Dark Zone, Fundic Gland Region, Stomach, Dog">Dark Zone, Fundic Gland Region, Stomach, Dog. The mucosa of the dark zone of the fundic stomach of carnivores is thicker than that of the light zone. The gastric pits are comparatively shallow, extending no farther into the mucosa than one-third of its thickness. Compare with Figure 13.62. Gastric pit Parietal cells Parietal cells Muscularis mucosae Chief cells Chief cells </entry>
<entry linktype="AI" linkname="EUR-013-066" title="Figure 13.66: Dark Zone, Fundic Gland Region, Stomach, Dog (PAS)">Dark Zone, Fundic Gland Region, Stomach, Dog (PAS). The surface mucous cells lining the lumen, cells of the gastric pits and the mucous neck cells of the glands, both contain complex carbohydrates and are PAS positive (magenta stain). Surface mucous cells Gastric pit Mucous neck cells Mucous neck cells Fundic glands Fundic glands </entry>
<entry linktype="AI" linkname="EUR-013-067" title="Figure 13.67: Lamina Subglandularis, Fundic Gland Region, Stomach, Cat (Old)">Lamina Subglandularis, Fundic Gland Region, Stomach, Cat (Old). A thick layer of connective tissue, the stratum compactum, and an overlying layer of fibroblasts, the stratum granulosum, together form the lamina subglandularis, a structure seen consistently in cats and occasionally in dogs. Presumably, the lamina subglandularis protects the stomach from punctures by sharp objects. Lamina propria Stratum granulosum Lamina propria Stratum granulosum Fundic glands Stratum compactum Muscularis mucosae </entry>
<entry linktype="AI" linkname="EUR-013-068" title="Figure 13.68: Fundic Gland Region, Stomach, Cat">Fundic Gland Region, Stomach, Cat. The fundic glands have been cut longitudinally. They are formed largely from parietal and chief cells. Lamina propria Fundic gland, lumen Smooth muscle Parietal cells Chief cells </entry>
<entry linktype="AI" linkname="EUR-013-070" title="Figure 13.70: Junction of the Cardiac and Fundic Gland Regions, Stomach, Horse">Junction of the Cardiac and Fundic Gland Regions, Stomach, Horse. The mucous glands of the cardiac gland region are distinct from the parietal and chief cells of the fundic gland region of the stomach. Cardiac glands Fundic glands Muscularis mucosae </entry>
<entry linktype="AI" linkname="EUR-013-071" title="Figure 13.71: Fundic Gland Region, Stomach, Horse">Fundic Gland Region, Stomach, Horse. The presence of surface mucous cells is a unique feature of the epithelium of the glandular stomach. Mucigen, the precursor of mucus, fills much of the apical portion of these cells in living tissue. Epithelial cells, surface cut Simple columnar epithelium Mucous precursor Gastric pit Gastric pit Lamina propria </entry>
<entry linktype="AI" linkname="EUR-013-073" title="Figure 13.73: Fundic Gland Region, Abomasum, Goat">Fundic Gland Region, Abomasum, Goat. Parietal and chief cells of the glands are evident. Note the deep gastric pits. Gastric pit Parietal cells Muscularis mucosae Chief cells Adipose tissue </entry>
<entry linktype="AI" linkname="EUR-013-074" title="Figure 13.74: Fundic Gland Region, Abomasum, Cow">Fundic Gland Region, Abomasum, Cow. Parietal and chief cells of the fundic glands. Globular leukocyte Lamina propria Parietal cell Chief cell </entry>
<entry linktype="AI" linkname="EUR-013-075" title="Figure 13.75: Mucosa, Pyloric Gland Region, Stomach, Dog (PAS)">Mucosa, Pyloric Gland Region, Stomach, Dog (PAS). The content of the surface mucous cells and that of the secretory units of the pyloric glands are PAS positive (magenta color). Surface mucous cells Gastric pit Lamina propria Pyloric gland Muscularis mucosae </entry>
<entry linktype="AI" linkname="EUR-013-076" title="Figure 13.76: Surface Mucous Cells, Pyloric Gland Region, Stomach, Dog">Surface Mucous Cells, Pyloric Gland Region, Stomach, Dog. Columnar cells lining the gastric pits and bordering the gastric lumen show typical cup-shaped concentrations of mucous precursor (mucigen) in their apical ends. The epithelium contains many migrating lymphocytes. Surface mucous cells Surface mucous cells Mucous precursor Lymphocytes Simple columnar epithelium, oblique section Gastric pit Mucous precursor Simple columnar epithelium, oblique section Lamina propria Lamina propria Simple columnar epithelium </entry>
<entry linktype="AI" linkname="EUR-013-077" title="Figure 13.77: Pyloric Gland Region, Stomach, Cat">Pyloric Gland Region, Stomach, Cat. Note the deep gastric pits. Some extend halfway through the thickness of the mucosa. Gastric pit Pyloric gland Muscularis mucosae Lamina subglandularis Submucosa Serosa Muscularis externa </entry>
<entry linktype="AI" linkname="EUR-013-078" title="Figure 13.78: Mucosa, Pyloric Gland Region, Stomach, Cat">Mucosa, Pyloric Gland Region, Stomach, Cat. Note the presence of deep gastric pits. Some extend to about half the depth of the mucosa. Surface mucous cells Lamina propria Pyloric gland Lamina subglandularis Gastric pit Muscularis mucosae </entry>
<entry linktype="AI" linkname="EUR-013-079" title="Figure 13.79: Pyloric Gland Region, Stomach, Cat">Pyloric Gland Region, Stomach, Cat. Basal ends of pyloric glands and the stratum granulosum and stratum compactum of the lamina subglandularis are present in this section. Stratum granulosum Arteriole Stratum granulosum Stratum compactum Muscularis mucosae Arteriole Pyloric gland Lamina propria </entry>
<entry linktype="AI" linkname="EUR-013-081" title="Figure 13.81: Junction, Pyloric Gland Region and Duodenum, l.s., Do">Junction, Pyloric Gland Region and Duodenum, l.s., Dog. Brynner's glands are located primarily in the submucosa of the duodenum. They also extend a short distance into the pyloric gland region of the stomach. They occasionally break through the muscularis mucosae and extend into the lamina propria. Villus of duodenum Lamina propria Gastric pit Lamina propria Crypt of Lieberkuhn Pyloric gland Muscularis mucosae Pyloric gland Brunner's gland Muscularis externa Junction, pyloric gland region and duodenum </entry>
<entry linktype="AI" linkname="EUR-013-082" title="Figure 13.82: Junction, Pyloric Gland Region and Duodenum, l.s., Dog">Junction, Pyloric Gland Region and Duodenum, l.s., Dog. Gastric pits and mucous glands of the pyloric gland region of the stomach can be seen. Brynner's glands (mucous) occur below the interrupted muscularis mucosae. See Figure 13.83 for detail of the epithelium. Gastric pit Lamina propria Pyloric gland Muscularis mucosae Brunner's gland Crypt of Lieberkuhn Brunner's gland Villus of duodenum Lamina propria Crypt of Lieberkuhn Muscularis mucosae Junction, pyloric gland region and duodenum </entry>
<entry linktype="AI" linkname="EUR-013-083" title="Figure 13.83: Junction, Pyloric Gland Region and Duodenum, Dog">Junction, Pyloric Gland Region and Duodenum, Dog. Note the change in the epithelium when it passes from the stomach to the duodenum. Typical columnar surface mucous cells of the pyloric gland region of the stomach contrast with the columnar absorptive cells and goblet cells of the duodenum. Lamina propria Lymphocytes Surface mucous cells, stomach Central lacteal Lamina propria Goblet cell Intestinal absorptive cells Striated border Goblet cell </entry>
<entry linktype="AI" linkname="EUR-013-084" title="Figure 13.84: Brunner's Gland, Duodenum, l.s., Dog">Brynner's Gland, Duodenum, l.s., Dog. Detail of mucous secretory units. The latter, in the dog, are lined by tall columnar cells and have large lumens. Compare with Figure 13.90. Secretory unit Secretory unit </entry>
<entry linktype="AI" linkname="EUR-013-085" title="Figure 13.85: Duodenum, x.s., Cat">Duodenum, x.s., Cat. A segment of the wall of the duodenum is shown. The intestinal villi of carnivores tend to be longer than those of noncarnivores. Note the shrinkage artifact at the apical ends of the villi. Villus Villus Artifact Submucosa Crypt of Lieberkuhn Muscularis mucosae Muscularis externa Serosa </entry>
<entry linktype="AI" linkname="EUR-013-086" title="Figure 13.86: Duodenum, Proximal, x.s., Cat (Masson's)">Duodenum, Proximal, x.s., Cat (Masson's). Ducts of Brynner's glands penetrate the muscularis mucosae. Brynner's glands are marked off into distinct lobules in the cat. Muscularis mucosae Crypt of Lieberkuhn Goblet cell Duct Muscularis mucosae Submucosa Brunner's gland Brunner's gland </entry>
<entry linktype="AI" linkname="EUR-013-087" title="Figure 13.87: Duodenum, x.s., Cat (Masson's)">Duodenum, x.s., Cat (Masson's). The submucosa in the cat and dog is a moderately dense irregular connective tissue. In other domestic mammals, it is a loose connective tissue. Muscularis mucosae Crypt of Lieberkuhn Crypt of Lieberkuhn Submucosa </entry>
<entry linktype="AI" linkname="EUR-013-088" title="Figure 13.88: Epithelium of Villus, Duodenum, Cat">Epithelium of Villus, Duodenum, Cat. Lymphocytes can be seen migrating through the simple columnar epithelium. Note the presence of several globular leukocytes. Lamina propria Lamina propria Globular leukocyte Striated border Lymphocyte Lymphocyte Lamina propria </entry>
<entry linktype="AI" linkname="EUR-013-089" title="Figure 13.89: Duodenum, Horse">Duodenum, Horse. Paneth cells are visible in the basal portions of the crypts of Lieberkyhn in the small intestine of the horse. Paneth cell Lamina propria Crypt of Lieberkuhn Paneth cell </entry>
<entry linktype="AI" linkname="EUR-013-090" title="Figure 13.90: Duodenum, Horse">Duodenum, Horse. In the horse, Brynner's glands have both mucous and serous components. Note that the lumens of the secretory units are small. Compare with Figure 13.84. Serous gland Mucous gland </entry>
<entry linktype="AI" linkname="EUR-013-092" title="Figure 13.92: Duodenum, Pig">Duodenum, Pig. In the pig the lumens of the secretory units of Brynner's glands are very small. Secretory unit Secretory unit Adipose cell </entry>
<entry linktype="AI" linkname="EUR-013-093" title="Figure 13.93: Duodenum, l.s., Cow">Duodenum, l.s., Cow. Brynner's glands are present throughout much of the submucosa of an intestinal fold (plica). Mucosa Brunner's gland Muscularis externa, inner circular </entry>
<entry linktype="AI" linkname="EUR-013-094" title="Figure 13.94: Duodenum, Cow">Duodenum, Cow. Detail of Brynner's gland. In the cow, some gland cells have an acidophilic cytoplasm. The lumens of secretory units are large. Crypt of Lieberkuhn Secretory unit Secretory unit Muscularis mucosae </entry>
<entry linktype="AI" linkname="EUR-013-095" title="Figure 13.95: Duodenum, x.s., Sheep">Duodenum, x.s., Sheep. The muscularis externa of the intestine is arranged into an inner circular and outer longitudinal layer of smooth muscle. Compare the appearance of the muscle layers seen in this cross section with that of the longitudinal section of the intestine in Figure 13.96. Submucosa Muscularis externa, inner circular Nerve fascicle, unmyelinated Muscularis externa, outer longitudinal Serosa </entry>
<entry linktype="AI" linkname="EUR-013-096" title="Figure 13.96: Duodenum, l.s., Sheep">Duodenum, l.s., Sheep. This section is through the muscularis externa. Compare the appearance of the muscle layers in this preparation with that in Figure 13.95. Submucosa Muscularis externa, inner circular Muscularis externa, outer longitudinal Serosa </entry>
<entry linktype="AI" linkname="EUR-013-097" title="Figure 13.97: Duodenum, Goat">Duodenum, Goat. Portions of the mucosa and submucosa. The lumens of the secretory units of Brynner's glands are large in the goat. Crypt of Lieberkuhn Muscularis mucosae Submucosa Secretory unit </entry>
<entry linktype="AI" linkname="EUR-013-098" title="Figure 13.98: Jejunum, x.s., Dog">Jejunum, x.s., Dog. A Meissner's plexus is present in the periphery of the submucosa. An Auerbach's plexus is wedged between the inner circular and outer longitudinal layers of the muscularis externa. Muscularis mucosae Submucosa Meissner’s plexus Crypt of Lieberkühn Muscularis externa, inner circular Auerbach’s plexus Muscularis externa, outer longitudinal </entry>
<entry linktype="AI" linkname="EUR-013-099" title="Figure 13.99: Jejunum, Dog">Jejunum, Dog. A well-developed stratum compactum is present between the lamina propria and muscularis mucosae of the small intestine in some cats and dogs. Crypt of Lieberk├╝hn Muscularis mucosae Stratum compactum Submucosa Crypt of Lieberk├╝hn Lamina propria </entry>
<entry linktype="AI" linkname="EUR-013-100" title="Figure 13.100: Jejunum, x.s., Cat">Jejunum, x.s., Cat. Slender villi and well-defined crypts of Lieberkyhn are evident. Intestinal lumen Villus Villus Lamina propria Crypt of Lieberk├╝hn Crypt of Lieberk├╝hn Crypt of Lieberk├╝hn Submucosa Muscularis externa, inner circular </entry>
<entry linktype="AI" linkname="EUR-013-101" title="Figure 13.101: Jejunum, Cat">Jejunum, Cat. Transverse sections of villi. Central lacteals are evident in two of them. Migrating lymphocytes are visible within the epithelium. Columnar epithelium Lamina propria Globular leukocyte Central lacteal, x.s. Globular leukocyte Villus Central lacteal, x.s. </entry>
<entry linktype="AI" linkname="EUR-013-102" title="Figure 13.102: Jejunum, Cat">Jejunum, Cat. Globular leukocytes are present among the columnar cells lining a crypt of Lieberkyhn. Numerous eosinophils are scattered through the lamina propria. Eosinophil Crypt of Lieberkuhn Globular leukocyte Nuclei of epithelium cut obliquely Lamina propria Eosinophil Lamina propria </entry>
<entry linktype="AI" linkname="EUR-013-103" title="Figure 13.103: Jejunum, l.s., Horse">Jejunum, l.s., Horse. All layers of the wall are included in this section. The villi are shorter than those of carnivores. Crypt of Lieberkuhn Villus Submucosa </entry>
<entry linktype="AI" linkname="EUR-013-104" title="Figure 13.104: Ileum, x.s., Cat">Ileum, x.s., Cat. A portion of the wall from the lumen to the serosa is shown. The epithelium of the villi contain numerous goblet cells. Serosa Muscularis externa, outer longitudinal Muscularis externa, inner circular Submucosa Crypt of Lieberkuhn Goblet cell Goblet cell Villus Villus </entry>
<entry linktype="AI" linkname="EUR-013-105" title="Figure 13.105: Ileum, Dog">Ileum, Dog. Mitotic figures can be seen in the crypts. Lamina propria Muscularis mucosae Crypt of Lieberkuhn Eosinophil Eosinophil Crypt of Lieberkuhn Mitotic figure </entry>
<entry linktype="AI" linkname="EUR-013-106" title="Figure 13.106: Cecum, Tip, Dog">Cecum, Tip, Dog. Large lymphatic nodules are present in the submucosa. Lymphatic nodule Lymphatic nodule Submucosa Mucosa Muscularis externa, inner circular Muscularis externa, outer longitudinal </entry>
<entry linktype="AI" linkname="EUR-013-107" title="Figure 13.107: Cecum, Dog">Cecum, Dog. Numerous goblet cells in the lining of the crypts of Lieberkyhn are characteristic of the organ. The epithelial cells bordering the lumen in this preparation have undergone some autolysis and look tattered. Muscularis externa, inner circular Submucosa Muscularis mucosae Crypt of Lieberkuhn Goblet cell Goblet cell Crypt of Lieberkuhn </entry>
<entry linktype="AI" linkname="EUR-013-108" title="Figure 13.108: Cecum, Dog">Cecum, Dog. Several crypts of Lieberkyhn appear in cross section. A striated border is present on the columnar cells. Goblet cells are numerous. Lamina propria Crypt of Lieberk├╝hn Lamina propria Goblet cell Crypt of Lieberk├╝hn Striated border </entry>
<entry linktype="AI" linkname="EUR-013-109" title="Figure 13.109: Cecal Band, x.s., Horse">Cecal Band, x.s., Horse. A cecal band consists of an admixture of smooth muscle (thickened outer longitudinal layer of the muscularis externa) and elastic fibers. Elastic fibers are predominant in the bands of both the cecum and the ventral large colon of the horse. Compare with Figure 13.112. Mucosa Serosa Cecal band Vein Muscularis externa, inner circular Submucosa </entry>
<entry linktype="AI" linkname="EUR-013-110" title="Figure 13.110: Cecum, Horse">Cecum, Horse. Veins with bands of smooth muscle in their walls are common in the submucosa throughout the digestive tract of the horse. Similar vessels are shown at low magnification in Figure 13.109. Small artery Muscle band Vein Small artery Vein Muscle band </entry>
<entry linktype="AI" linkname="EUR-013-111" title="Figure 13.111: Cecum, Cow">Cecum, Cow. In the large intestine of ruminants, the crypts of Lieberkyhn are usually tortuous. Adipose tissue is abundant in the submucosa. Adipose tissue Muscularis mucosae Lymphatic nodule Crypt of Lieberk├╝hn Crypt of Lieberk├╝hn </entry>
<entry linktype="AI" linkname="EUR-013-112" title="Figure 13.112: Taenia Coli, Small Colon, x.s., Horse">Taenia Coli, Small Colon, x.s., Horse. The taenia coli are thickenings of the outer longitudinal layer of the muscularis externa. In contrast to the bands of the cecum and ventral large colon, where elastic fibers are predominant, smooth muscle predominates in the bands of the small colon and dorsal large colon. Compare with Figure 13.109. Taenia coli </entry>
<entry linktype="AI" linkname="EUR-013-113" title="Figure 13.113: Taenia Coli, Colon, x.s., Pig">Taenia Coli, Colon, x.s., Pig. The muscular taenia coli is formed from the outer longitudinal layer of the muscularis externa. The submucosa is infiltrated with fat. Muscularis externa, inner circular Muscularis externa, outer longitudinal Adipose tissue Mucosa Taenia coli </entry>
<entry linktype="AI" linkname="EUR-013-114" title="Figure 13.114: Spiral Colon. x.s., Goat">Spiral Colon. x.s., Goat. The mucosa contains both tortuous and straight crypts of Lieberkyhn. The muscularis externa shows an abrupt thickening of its inner circular layer and outer longitudinal layer. Adipose tissue Crypt of Lieberkuhn Crypt of Lieberkuhn Muscularis externa, outer longitudinal Muscularis externa, inner circular Mucosa </entry>
<entry linktype="AI" linkname="EUR-013-115" title="Figure 13.115: Spiral Colon. x.s., Goat">Spiral Colon, x.s., Goat. The columnar epithelial cells have a distinct striated border. Lamina propria Lamina propria Striated border Striated border </entry>
<entry linktype="AI" linkname="EUR-013-116" title="Figure 13.116: Rectum, x.s., Cat">Rectum, x.s., Cat. The epithelium of the rectum presents a flat, uniform surface. Goblet cell Crypt of Lieberkuhn Crypt of Lieberkuhn Muscularis mucosae Submucosa </entry>
<entry linktype="AI" linkname="EUR-013-117" title="Figure 13.117: Rectoanal Junction, l.s., Dog">Rectoanal Junction, l.s., Dog. Note that the anal glands mark the junction (arrow) of the rectum and anal canal. Mucosa Submucosa Rectum Submucosa Anal canal Muscularis externa, inner circular Anal glands Circumanal glands Epidermis External anal sphincter Muscularis externa, outer longitudinal Glands of anal sac External anal sphincter </entry>
<entry linktype="AI" linkname="EUR-013-118" title="Figure 13.118: Rectoanal Junction, l.s., Dog">Rectoanal Junction, l.s., Dog. Note the change between the stratified squamous epithelium of the anal canal and the crypts of Lieberkyhn of the rectal mucosa. Note also that anal glands are located in the submucosa and are scattered among the smooth muscle of the internal anal sphincter (inner circular layer of the muscularis externa). See Figure 13.117 for orientation.</entry>
<entry linktype="AI" linkname="EUR-013-119" title="Figure 13.119: Anal Glands, Dog">Anal Glands, Dog. Section is through the secretory units of an anal gland. Anal gland External anal sphincter </entry>
<entry linktype="AI" linkname="EUR-013-120" title="Figure 13.120: Glands of the Anal Sac, Dog">Glands of the Anal Sac, Dog. A small portion of the wall of an anal sac and the secretory units of some of the glands of the anal sac are shown. See Figure 13.117 for location. External anal sphincter Apocrine tubular gland Apocrine tubular gland Apocrine tubular gland Keratinized epithelium of anal sac </entry>
<entry linktype="AI" linkname="EUR-013-121" title="Figure 13.121: Anal Sac, Cat">Anal Sac, Cat. About one-half of the wall of an anal sac is shown. External anal sphincter Sebaceous gland Debris in anal sac External anal sphincter Apocrine tubular gland Apocrine tubular gland </entry>
<entry linktype="AI" linkname="EUR-013-122" title="Figure 13.122: Glands of the Anal Sac, Cat">Glands of the Anal Sac, Cat. Portions of these glands are shown adjacent to the skeletal muscle of the external anal sphincter. The presence of sebaceous glands in this location is a characteristic of the cat. External anal sphincter Apocrine tubular gland Apocrine tubular gland Sebaceous gland Sebaceous gland </entry>
<entry linktype="AI" linkname="EUR-013-123" title="Figure 13.123: Anal Canal, l.s., Dog">Anal Canal, l.s., Dog. Junction of the keratinized and nonkeratinized regions of the anal canal. The stratum granulosum of the keratinized region stops abruptly at the junction. Sebaceous gland Stratum granulosum </entry>
<entry linktype="AI" linkname="EUR-013-124" title="Figure 13.124: Circumanal Glands, Dog">Circumanal Glands, Dog. Numerous nonsebaceous portions of circumanal glands are present subcutaneously among the skeletal muscle of the anal sphincter. These nonsebaceous portions are often called hepatoid glands because their cells resemble hepatocytes. Circumanal gland, nonsebaceous Circumanal gland, nonsebaceous Circumanal gland, nonsebaceous Skeletal muscle Circumanal gland, sebaceous Circumanal gland, sebaceous Keratinized epidermis </entry>
<entry linktype="AI" linkname="EUR-013-125" title="Figure 13.125: Circumanal Glands, Dog">Circumanal Gland, Dog. Detail of a part of one of the glands. The lower, nonsebaceous portion of these glands is more acidophilic than the upper, sebaceous portion. Circumanal gland, nonsebaceous Hair follicle Circumanal gland, sebaceous </entry>
<entry linktype="AI" linkname="EUR-013-126" title="Figure 13.126: Rectoanal Junction, l.s., Horse">Rectoanal Junction, l.s., Horse. The stratified squamous epithelium of the anal canal contrasts with the rectal mucosa. Crypt of Lieberkuhn Crypt of Lieberkuhn Simple columnar epithelium Stratified squamous epithelium </entry>
<entry linktype="AI" linkname="EUR-013-127" title="Figure 13.127: Rectoanal Junction, Horse">Rectoanal Junction, Horse. The abrupt change between the stratified squamous epithelium of the anal canal and the simple columnar epithelium of the rectal mucosa is apparent. Crypt of Lieberkuhn Lamina propria Stratified squamous epithelium Goblet cell Simple columnar epithelium </entry>
<entry linktype="AI" linkname="EUR-013-128" title="Figure 13.128: Liver, Cat">Liver, Cat. Transverse and longitudinal sections through the central veins of two classic lobules. Central vein, l.s. Central vein, x.s. Serosa </entry>
<entry linktype="AI" linkname="EUR-013-129" title="Figure 13.129: Liver, Cat">Liver, Cat. Transverse section through a classic lobule. Sinusoids empty into the central vein. Hepatocytes radiate as hepatic plates from the central vein. Central vein, x.s. Hepatocyte Nucleus of hepatocyte Sinusoid Hepatocyte Sinusoid </entry>
<entry linktype="AI" linkname="EUR-013-130" title="Figure 13.130: Liver, Cat">Liver, Cat. The portal tract in this section includes a branch of the hepatic portal vein and hepatic artery, bile ductule, and lymphatic vessel. Portal vein, branch Hepatocyte Lymphatic vessel Hepatocyte Bile ductile Bile ductile Lymphatic vessel Hepatic artery, branch </entry>
<entry linktype="AI" linkname="EUR-013-131" title="Figure 13.131: Liver, Horse">Liver, Horse. A portal tract is at the intersection of three classic lobules. Branches of the portal vein can be seen extending between the lobules. Hepatocyte Bile ductile Portal vein, branch Lobule, portion of Hepatic artery, branch Hepatocyte Portal vein, branch Lobule, portion of Hepatocyte Portal vein, branch Lobule, portion of </entry>
<entry linktype="AI" linkname="EUR-013-132" title="Figure 13.132: Liver, Cat (Masson's)">Liver, Cat (Masson's). Sections through various bile canaliculi are evident in this section. Hepatocyte Sinusoid Nucleus of hepatocyte Bile canaliculus, x.s. Bile canaliculus, x.s. Nucleus of hepatocyte Bile canaliculus, l.s. Hepatocyte Sinusoid Nucleus of hepatocyte Bile canaliculus, l.s. </entry>
<entry linktype="AI" linkname="EUR-013-133" title="Figure 13.133: Liver, Horse">Liver, Horse. A sinusoid joins with a branch of the portal vein. Sinusoid Hepatocyte Hepatocyte Sinusoid Portal vein, branch </entry>
<entry linktype="AI" linkname="EUR-013-134" title="Figure 13.134: Liver, Horse">Liver, Horse. Section is through mesothelial cells and connective tissue of the capsule of Glisson surrounding the liver. Together, the mesothelial cells and the capsule of Glisson comprise the serosa. Mesothelium Sinusoid Hepatocyte Capsule of Glisson </entry>
<entry linktype="AI" linkname="EUR-013-135" title="Figure 13.135: Liver, Pig">Liver, Pig. Classic lobules are clearly separated from one another by partitions of connective tissue in the pig. Portal tract Connective tissue, partition of Central vein Portal tract </entry>
<entry linktype="AI" linkname="EUR-013-136" title="Figure 13.136: Liver, Pig">Liver, Pig. Particulate-laden Kupffer cells within sinusoids of a classic lobule are evident in this section. Binucleate hepatocytes also can be seen. Binucleate hepatocyte Kupffer cell Sinusoid Binucleate hepatocyte Kupffer cell </entry>
<entry linktype="AI" linkname="EUR-013-137" title="Figure 13.137: Liver, Goat">Liver, Goat. A large bile duct with columnar epithelium and goblet cells. Bile duct Goblet cell </entry>
<entry linktype="AI" linkname="EUR-013-138" title="Figure 13.138: Gallbladder, Dog">Gallbladder, Dog. A portion of the wall showing the highly folded mucosa. Epithelium Lamina propria Gallbladder, lumen Muscularis Adventitia Mucosa </entry>
<entry linktype="AI" linkname="EUR-013-139" title="Figure 13.139: Gallbladder, Dog">Gallbladder, Dog. Epithelial lining with light and dark columnar cells. Dark cell Light cell Gallbladder, lumen Lamina propria Striated border Dark cell Dark cell </entry>
<entry linktype="AI" linkname="EUR-013-140" title="Figure 13.140: Gallbladder and Liver, Pig (Masson's)">Gallbladder and Liver, Pig (Masson's). Section shows a portion of the liver and gallbladder. Adventitia Liver Gallbladder, lumen Mucosa Muscularis </entry>
<entry linktype="AI" linkname="EUR-013-141" title="Figure 13.141: Gallbladder, Goat">Gallbladder, Goat. Portion of a mucosal fold showing goblet cells in the epithelium. Lamina propria Goblet cell </entry>
<entry linktype="AI" linkname="EUR-013-142" title="Figure 13.142: Gallbladder, Goat">Gallbladder, Goat. Mixed glands occur within the wall of the gallbladder of ruminants. Epithelium Mucous acinus Muscularis Muscularis Lamina propria Epithelium Serous acinus </entry>
<entry linktype="AI" linkname="EUR-013-143" title="Figure 13.143: Cystic Duct, Pig">Cystic Duct, Pig. The epithelium is composed of light cells, dark cells, and goblet cells. Acinus Goblet cell Acinus Light cell Anastomotic artery Muscularis </entry>
<entry linktype="AI" linkname="EUR-013-144" title="Figure 13.144: Pancreas, Horse">Pancreas, Horse. The organ is divided into lobules by septa of connective tissue. Most of the pancreas is formed from exocrine acinar cells. Islets of Langerhans are scattered through the exocrine region of the gland. A cells </entry>
<entry linktype="AI" linkname="EUR-013-145" title="Figure 13.145: Pancreas, Horse">Pancreas, Horse. Portions of two lobules showing acinar cells, interlobular ducts, and intercalated (intralobular) ducts. Acinus Goblet cell Dark cell Light cell Anastomotic artery Muscularis </entry>
<entry linktype="AI" linkname="EUR-013-146" title="Figure 13.146: Pancreas, Horse">Pancreas, Horse. An islet of Langerhans with some surrounding exocrine acini. In the horse, the darker A cells are located in the center of the islet, while the lighter B cells are positioned in the periphery. Compare with Figure 13.150. Note the numerous capillaries among cords of islet cells. Capillary B cells Acinus Acinus A cells Acinus </entry>
<entry linktype="AI" linkname="EUR-013-147" title="Figure 13.147: Pancreas, Dog">Pancreas, Dog. Detail of acini and intercalated ducts. Note acidophilic apical regions and basophilic basal regions of the acinar cells. Intercalated duct, x.s. Acinar cells Centroacinar cell Centroacinar cell Intercalated duct, l.s. Intercalated duct, l.s. Acinar cells </entry>
<entry linktype="AI" linkname="EUR-013-148" title="Figure 13.148: Pancreas, Pig">Pancreas, Pig. An interlobular duct with goblet cells interspersed among the epithelial cells of the duct. Acinus Goblet cell Goblet cell Acinus </entry>
<entry linktype="AI" linkname="EUR-013-149" title="Figure 13.149: Pancreas, Cow (Masson's)">Pancreas, Cow (Masson's). An intercalated duct enters an acinus. Islet of Langerhans Intercalated duct </entry>
<entry linktype="AI" linkname="EUR-013-150" title="Figure 13.150: Pancreas, Sheep (Masson's)">Pancreas, Sheep (Masson's). In ruminants, darkly stained A cells are located at the periphery of the islets of Langerhans, while light-staining B cells are centrally located. Compare with Figure 13.146. A cell A cell B cells Acinus </entry>
<entry linktype="AI" linkname="EUR-013-151" title="Figure 13.151: Tongue, Tip, l.s., Chicken">Tongue, Tip, l.s., Chicken. The upper surface of the tongue is covered by a thick stratified squamous epithelium, which is keratinized near the tip. The stratified squamous epithelium of the lower surface is thinner and also keratinized rostrally. The tongue is supported by hyaline cartilage rostrally. The ducts of salivary glands (mucous) open at the lower surface. Stratified squamous epithelium Salivary gland Hyaline cartilage Duct Duct Stratified squamous epithelium </entry>
<entry linktype="AI" linkname="EUR-013-152" title="Figure 13.152: Taste Bud, Tongue, Base, Chicken">Taste Bud, Tongue, Base, Chicken. A taste bud (characteristically large and scarce in the chicken) can be seen closely associated with the duct of a salivary gland. For detail of the taste bud, see Figure 13.153. Salivary gland Duct Taste bud Stratified squamous epithelium Salivary gland </entry>
<entry linktype="AI" linkname="EUR-013-153" title="Figure 13.153: Taste Bud, Chicken">Taste Bud, Chicken. Detail of the taste bud seen in Figure 13.152. Its cells stain lightly with eosin. Numerous spaces occur between cells. A taste bud pore is visible. Taste bud cell Taste bud cell Intercellular space Intercellular space Pore </entry>
<entry linktype="AI" linkname="EUR-013-154" title="Figure 13.154: Esophagus, x.s., Chicken">Esophagus, x.s., Chicken. The esophagus is lined by a thick nonkeratinized stratified squamous epithelium. Mucous glands occur in the lamina propria. The submucosa is sparse. Stratified squamous epithelium Lamina propria Submucosa Muscularis externa Muscularis mucosae Mucous gland Serosa Submucosa </entry>
<entry linktype="AI" linkname="EUR-013-155" title="Figure 13.155: Crop, Chicken">Crop, Chicken. The crop is a diverticulum of the esophagus. Unlike the latter, it lacks mucous glands, except close to its junction with the esophagus. Lamina propria Muscularis mucosae Submucosa Stratified squamous epithelium Muscularis externa </entry>
<entry linktype="AI" linkname="EUR-013-156" title="Figure 13.156: Proventriculus (Glandular Stomach), x.s., Chicken">Proventriculus (Glandular Stomach), x.s., Chicken. The submucosa contains lobules of compound tubular glands that are arranged around a central, secondary duct. A primary duct, which drains several lobules, opens through a raised mucosal papilla. Secondary duct Tertiary duct Gland Proventriculus, lumen Primary duct Secondary duct Tertiary duct Gland </entry>
<entry linktype="AI" linkname="EUR-013-157" title="Figure 13.157: Proventriculus, x.s., Chicken">Proventriculus, x.s., Chicken. A magnified view of Figure 13.156 shows that the mucosa of the papilla is arranged into folds (plicae) covered by columnar cells, and depressions (sulci) lined by shorter cells. A primary duct, lined by columnar cells, joins the lumen of the proventriculus. Primary duct Plica Proventriculus, lumen Sulcus Plica Sulcus Proventriculus, lumen </entry>
<entry linktype="AI" linkname="EUR-013-158" title="Figure 13.158: Proventriculus, x.s., Chicken">Proventriculus, x.s., Chicken. A tertiary duct branching from the secondary duct leads into a glandular unit. The glandular epithelial cells vary from simple cuboidal to low columnar and contain a grainy secretory material. These cells secrete both pepsinogen and HCl. Gland cell Secondary duct Tertiary duct Gland cell </entry>
<entry linktype="AI" linkname="EUR-013-159" title="Figure 13.159: Ventriculus (Gizzard), Chicken">Ventriculus (Gizzard), Chicken. The pink, thick layer of keratinoid that lines the ventriculus is produced by branched tubular gastric glands in the lamina propria. The submucosa and a portion of the smooth muscle layers of a thick muscularis externa are shown. Ventriculus, lumen Keratinoid Lamina propria Gastric pit Gastric gland Gastric gland Submucosa Muscularis externa </entry>
<entry linktype="AI" linkname="EUR-013-160" title="Figure 13.160: Ventriculus, Chicken">Ventriculus, Chicken. Keratinoid lines the mucosal surface and fills the lumen of the gastric pits and glands. The cells of the surface epithelium are low to tall columnar. The cells decrease in height as they extend into the gastric pits. Flattened cells (chief cells) line the upper and mid-regions of the tubular gastric glands seen in this micrograph. Branching of some of the glands is evident. Gastric pit Keratinoid Gastric gland Surface epithelium Lamina propria Gastric pit Chief cell Gastric gland Gastric gland </entry>
<entry linktype="AI" linkname="EUR-013-161" title="Figure 13.161: Ventriculus, Chicken">Ventriculus, Chicken. The flattened chief cells lining the mid-portion of the gastric glands become cuboidal to low columnar in the fundus of the gland. A few large basal cells with pale nuclei and pale cytoplasm occur in the fundus of the glands. Keratinoid Lamina propria Chief cell Chief cell Basal cell Submucosa </entry>
<entry linktype="AI" linkname="EUR-013-162" title="Figure 13.162: Duodenum, x.s., Chicken">Duodenum, x.s., Chicken. Lymphatic tissue (diffuse and nodular) in the duodenum close to the stomach. Villus Villus Crypt of Lieberk├╝hn Muscularis externa Lymphatic tissue </entry>
<entry linktype="AI" linkname="EUR-013-163" title="Figure 13.163: Duodenum, x.s., Chicken (Mallory's)">Duodenum, x.s., Chicken (Mallory's). The serosa is thick. The submucosa is characteristically sparse. Villus Submucosa Crypt of Lieberk├╝hn Muscularis mucosae Muscularis externa Submucosa Serosa </entry>
<entry linktype="AI" linkname="EUR-013-164" title="Figure 13.164: Ileum, x.s., Chicken">Ileum, x.s., Chicken. Villi are long and slender with numerous goblet cells. The submucosa is thin. Villus Submucosa Crypt of Lieberk├╝hn Muscularis mucosae Muscularis externa </entry>
<entry linktype="AI" linkname="EUR-013-165" title="Figure 13.165: Cecum, Tip, l.s., Chicken">Cecum, Tip, l.s., Chicken. In the tip of the cecum, villi are short and broad. Compare Figure 11.51 of the cecal tonsil. Villus Crypt of Lieberk├╝hn Muscularis mucosae Submucosa Muscularis externa Serosa </entry>
<entry linktype="AI" linkname="EUR-013-166" title="Figure 13.166: Large Intestine, x.s., Chicken">Large Intestine, x.s., Chicken. Villi are present in the chicken's large intestine. Crypt of Lieberk├╝hn Submucosa Villus Serosa Muscularis externa </entry>
<entry linktype="AI" linkname="EUR-013-167" title="Figure 13.167: Cloaca, l.s., Chicken">Cloaca, l.s., Chicken. The cloaca is subdivided into three regions: the coprodeum, urodeum, and proctodeum. The large intestine is continuous with the coprodeum. The ureters and genital ducts terminate in the urodeum. The terminal proctodeum opens to the exterior through the cloacal lips. Proctodeum Lymphoglandular ridge Skeletal muscle Smooth muscle Cloacal lip, dorsal Cloacal lip, ventral Urodeum Smooth muscle Coprodeum </entry>
<entry linktype="AI" linkname="EUR-013-168" title="Figure 13.168: Coprodeum, Cloaca, Chicken">Coprodeum, Cloaca, Chicken. The mucosa of the coprodeum is thrown into short, flat villi. Shallow crypts of Lieberkyhn open at their bases. Simple columnar epithelium covers their surface. Simple columnar epithelium Villus Villus Crypt of Lieberkuhn Lymphatic nodule </entry>
<entry linktype="AI" linkname="EUR-013-169" title="Figure 13.169: Cloaca, l.s., Chicken">Cloaca, l.s., Chicken. Branched tubular glands (modified crypts) form a part of the lymphoglandular ridge of Jolly located in the dorsal proctodeum. The epithelium of the ridge consists of tall columnar cells. A portion of the stratified squamous epithelium of the inner surface of the ventral cloacal lip can be seen. Tubular gland Tubular gland Cloacal lip, ventral </entry>
<entry linktype="AI" linkname="EUR-013-170" title="Figure 13.170: Cloaca, l.s., Chicken">Cloaca, l.s., Chicken. A large Herbst corpuscle lies beneath the stratified squamous epithelium of the cloacal lip. These corpuscles typically occur close to the latter's point of juncture with the simple columnar epithelium of the proctodeum. Simple columnar epithelium Stratified squamous epithelium Herbst corpuscle </entry>
<entry linktype="AI" linkname="EUR-013-171" title="Figure 13.171: Liver, Chicken">Liver, Chicken. Central veins of several lobules are evident. One lobule is indicated by a dashed line. Central vein Lobule, margin of Central vein </entry>
<entry linktype="AI" linkname="EUR-013-172" title="Figure 13.172: Liver, Chicken">Liver, Chicken. Sinusoids can be seen entering a central vein. Radiating plates of hepatocytes are two cells thick in the chicken. Hepatocyte Acinus Erythrocytes Hepatocyte Sinusoid </entry>
<entry linktype="AI" linkname="EUR-013-173" title="Figure 13.173: Liver, Chicken (Silver)">Liver, Chicken (Silver). The wall of a central vein and surrounding plates of hepatocytes (whose cellular features are indistinct in this preparation) are supported by a network of reticular fibers that have been blackened with silver. Central vein Erythrocytes Reticular fibers Reticular fibers </entry>
<entry linktype="AI" linkname="EUR-013-174" title="Figure 13.174: Pancreas, Chicken">Pancreas, Chicken. Numerous portions of tubuloacinar serous glands surround an alpha islet of Langerhans. Alpha islets contain columnar A cells and are larger than beta islets. Erythrocytes in capillaries can be seen between cords of islet cells. Acinus Capillary A cells Capillary Acinus </entry>
<entry linktype="AI" linkname="EUR-013-175" title="Figure 13.175: Pancreas, Chicken">Pancreas, Chicken. Beta islets contain polygonal B cells and are smaller than alpha islets. B cell Acinus</entry>
<entry linktype="AI" linkname="EUR-014-001" title="Figure 14.1: Cortex and Portion of Medulla, Kidney, Dog">Cortex and Portion of Medulla, Kidney, Dog. Renal corpuscles are limited to the cortex. Capsule Renal corpuscle Pars radiata Pars convoluta Pars radiata Pars radiata Pars convoluta Renal corpuscle Medulla </entry>
<entry linktype="AI" linkname="EUR-014-002" title="Figure 14.2: Cortex, Kidney, Dog (Masson's)">Cortex, Kidney, Dog (Masson's). Pars radiata alternate with the pars convoluta. Capsule Adipose tissue Renal corpuscle Pars radiata Pars convoluta Pars radiata Renal corpuscle </entry>
<entry linktype="AI" linkname="EUR-014-003" title="Figure 14.3: Capsule and Superficial Cortex, Kidney, Cat">Capsule and Superficial Cortex, Kidney, Cat. The capsule of the kidney consists entirely of connective tissue in the cat. Capsule of kidney Proximal convoluted tubule Subcapsular vein Connective tissue Collecting tubule Proximal convoluted tubule </entry>
<entry linktype="AI" linkname="EUR-014-004" title="Figure 14.4: Capsule, Kidney, Sheep">Capsule, Kidney, Sheep. The inner portion of the capsule of the kidney of ruminants contains a distinct layer of smooth muscle. Smooth muscle is also present in the capsule of the dog, horse, and pig. Connective tissue Smooth muscle tissue Proximal convoluted tubule Proximal convoluted tubule Collecting tubule </entry>
<entry linktype="AI" linkname="EUR-014-005" title="Figure 14.5: Renal Corpuscle, Kidney, Puppy">Renal Corpuscle, Kidney, Puppy. In young animals, the podocytes of the visceral layer of Bowman's capsule have round to oval nuclei. Nucleus of podocyte Proximal convoluted tubule Proximal convoluted tubule Proximal convoluted tubule Bowman’s capsule, parietal layer Urinary space Nucleus of podocyte Distal convoluted tubule Distal convoluted tubule </entry>
<entry linktype="AI" linkname="EUR-014-006" title="Figure 14.6: Renal Corpuscle, Kidney, Cat">Renal Corpuscle, Kidney, Cat. Cells of the proximal convoluted tubules of the cat contain numerous fat vacuoles. A macula densa, consisting of closely packed cells, forms a portion of the wall of the distal convoluted tubule adjacent to the vascular pole of the renal corpuscle. Fat vacuole Distal convoluted tubule Proximal convoluted tubule Macula densa Urinary space </entry>
<entry linktype="AI" linkname="EUR-014-007" title="Figure 14.7: Cortex, Kidney, Horse">Cortex, Kidney, Horse. Portions of three renal corpuscles, each with an accompanying macula densa, are present. In the horse, the macula densa commonly consists of a stratified layer of cells. Distal convoluted tubule Distal convoluted tubule Collecting tubule Macula densa Proximal convoluted tubule Distal convoluted tubule Bowman's capsule, parietal layer Urinary space Proximal convoluted tubule Macula densa Macula densa Urinary space </entry>
<entry linktype="AI" linkname="EUR-014-008" title="Figure 14.8: Cortex, Kidney, Horse">Cortex, Kidney, Horse. A collecting tubule with clearly defined cells and a smooth lining can be contrasted with proximal convoluted tubules whose cells possess a brush border of microvilli. Brush border Proximal convoluted tubule Proximal convoluted tubule Brush border Collecting tubule </entry>
<entry linktype="AI" linkname="EUR-014-009" title="Figure 14.9: Cortex, Kidney, Pig">Cortex, Kidney, Pig. The junction of a proximal convoluted tubule with the Bowman's capsule of a renal corpuscle is shown. Proximal convoluted tubule Proximal convoluted tubule Distal convoluted tubule Distal convoluted tubule Urinary space Bowman's capsule, parietal layer </entry>
<entry linktype="AI" linkname="EUR-014-010" title="Figure 14.10: Afferent Arteriole, Kidney, Pig">Afferent Arteriole, Kidney, Pig. An afferent arteriole, with juxtaglomerular cells, is entering a glomerulus. The juxtaglomerular cells are epithelioid. Note that a macula densa borders the afferent arteriole. Urinary space Bowman's capsule, parietal layer Proximal convoluted tubule Macula densa Distal convoluted tubule Afferent arteriole Juxtaglomerular cells Proximal convoluted tubule Distal convoluted tubule </entry>
<entry linktype="AI" linkname="EUR-014-011" title="Figure 14.11: Afferent and Efferent Arterioles, Kidney, Pig">Afferent and Efferent Arterioles, Kidney, Pig. Junction of a glomerulus with an afferent arteriole. A macula densa parallels the afferent arteriole. Efferent arteriole Urinary space Afferent arteriole Macula densa Proximal convoluted tubule </entry>
<entry linktype="AI" linkname="EUR-014-012" title="Figure 14.12: Pars Radiata, l.s., Cortex, Kidney, Horse">Pars Radiata, l.s., Cortex, Kidney, Horse. The component tubules of a medullary ray include collecting tubules as well as thick descending and thick ascending portions of the loop of Henle. Thick ascending, Henle's loop Thick ascending, Henle's loop Thick ascending, Henle's loop Collecting tubule Thick descending, Henle's loop Collecting tubule </entry>
<entry linktype="AI" linkname="EUR-014-013" title="Figure 14.13: Renal Papilla, Kidney, Dog">Renal Papilla, Kidney, Dog. Papillary ducts open onto the tip of a renal papilla. Papillary duct Renal papilla Cavity of renal pelvis Adipose tissue </entry>
<entry linktype="AI" linkname="EUR-014-014" title="Figure 14.14: Medulla, Kidney, Dog">Medulla, Kidney, Dog. Nuclei of the cells lining the thin segment of Henle's loop are rounded; those of endothelial cells of the vasa recta are flattened and more darkly stained. Vasa recta Collecting tubule, surface cut Collecting tubule Thin segment, Henle's loop Vasa recta Collecting tubule </entry>
<entry linktype="AI" linkname="EUR-014-016" title="Figure 14.16: Medulla, Kidney, Cow (Trichrome)">Medulla, Kidney, Cow (Trichrome). Longitudinal sections of vasa rectae and portions of uriniferous tubules. The vasa rectae are filled with red blood cells (stained orange). Vasa recta Collecting tubule Thick ascending, Henle's loop Thick ascending, Henle's loop Vasa recta Collecting tubule </entry>
<entry linktype="AI" linkname="EUR-014-017" title="Figure 14.17: Renal Papilla, Kidney, Goat">Renal Papilla, Kidney, Goat. Papillary ducts near the tip of a renal papilla are lined by transitional epithelium. Vasa recta Thin segment, Henle's loop Thin segment, Henle's loop Papillary duct Thin segment, Henle's loop Papillary duct Vasa recta </entry>
<entry linktype="AI" linkname="EUR-014-018" title="Figure 14.18: Medulla, Kidney, Goat">Medulla, Kidney, Goat. A papillary duct, l.s., some distance away from the apex of the papilla, is lined by columnar cells. A thin segment of Henle's loop parallels the duct. Thin segment, Henle's loop Vasa recta Thin segment, Henle's loop Erythrocytes Papillary duct Erythrocytes </entry>
<entry linktype="AI" linkname="EUR-014-019" title="Figure 14.19: Medulla, Kidney, Goat (Silver)">Medulla, Kidney, Goat (Silver). The collecting tubules are encircled by reticular fibers (stained black). The fibers provide a supportive framework for other portions of the uriniferous tubules as well. Collecting tubule Collecting tubule Reticular fiber Reticular fiber </entry>
<entry linktype="AI" linkname="EUR-014-020" title="Figure 14.20: Urachus, Umbilical Cord, Cow">Urachus, Umbilical Cord, Cow. The urachus (allantoic stalk) is lined by a transitional epithelium. A portion of the lining is shown. Transitional epithelium Mucous connective tissue </entry>
<entry linktype="AI" linkname="EUR-014-021" title="Figure 14.21: Ureter, x.s., Cat (Masson's)">Ureter, x.s., Cat (Masson's). The middle circular layer of smooth muscle of the muscularis is most evident. Inner and outer longitudinal layers are present but sparse in this section. Lamina propria Transitional epithelium Lamina propria Muscularis Adventitia </entry>
<entry linktype="AI" linkname="EUR-014-022" title="Figure 14.22: Ureter, x.s., Horse (Masson's)">Ureter, x.s., Horse (Masson's). The proximal (anterior) portion of the horse's ureter contains tubuloalveolar mucous glands. Transitional epithelium Mucous gland Transitional epithelium Lamina propria Muscularis </entry>
<entry linktype="AI" linkname="EUR-014-023" title="Figure 14.23: Ureter, x.s., Horse">Ureter, x.s., Horse. Distally (posteriorly), the horse's ureter lacks mucous glands. The muscularis consists of an inner longitudinal, middle circular, and outer longitudinal layer of smooth muscle. Transitional epithelium Lamina propria Muscularis </entry>
<entry linktype="AI" linkname="EUR-014-024" title="Figure 14.24: Urinary Bladder, Pig">Urinary Bladder, Pig. The mucosa to a portion of the muscularis is shown. Scattered muscle cells of the muscularis mucosae are located adjacent to the lamina propria. Transitional epithelium Lamina propria Muscularis mucosae Muscularis mucosae Submucosa Muscularis </entry>
<entry linktype="AI" linkname="EUR-014-025" title="Figure 14.25: Urinary Bladder, Cow">Urinary Bladder, Cow. The bladder contains a muscularis mucosae between the lamina propria and submucosa. Only a portion of the thick muscularis is shown. Transitional epithelium Muscularis mucosae Lamina propria Submucosa Muscularis </entry>
<entry linktype="AI" linkname="EUR-014-026" title="Figure 14.26: Urinary Bladder, Goat">Urinary Bladder, Goat. Numerous capillaries are located beneath the transitional epithelial lining of the bladder of ruminants. Capillary Transitional epithelium Capillary Lamina propria </entry>
<entry linktype="AI" linkname="EUR-014-027" title="Figure 14.27: Kidney, Chicken">Kidney, Chicken. Cortical parenchyma and portion of a medullary cone are shown. An intralobular vein and both cortical (small) and medullary (large) renal corpuscles are apparent. Cortex Intralobular vein Renal corpuscle, smal Cortex Renal corpuscle, large Medullary cone </entry>
<entry linktype="AI" linkname="EUR-014-028" title="Figure 14.28: Kidney, Chicken">Kidney, Chicken. A portion of a medullary cone is surrounded by cortical lobules. The intralobular veins of two cortical lobules are clearly represented. Medullary cone Renal corpuscle, large Renal corpuscle, smal Intralobular vein Intralobular vein </entry>
<entry linktype="AI" linkname="EUR-014-029" title="Figure 14.29: Cortex, Kidney, Chicken">Cortex, Kidney, Chicken. An intralobular vein is surrounded by cortical tissue. Distal convoluted tubules are located mainly in the region of the intralobular vein. Proximal convoluted tubule Distal convoluted tubule Distal convoluted tubule Proximal convoluted tubule Intralobular vein Proximal convoluted tubule </entry>
<entry linktype="AI" linkname="EUR-014-030" title="Figure 14.30: Cortex, Kidney, Chicken">Cortex, Kidney, Chicken. In the chicken, the visceral layer of Bowman's capsule is composed of podocytes that have large round or oval nuclei. The center of the glomerulus contains a compact mass of mesangial cells. Collecting tubule Erythrocytes Nucleus of podocyte Urinary space Mesangial cells Distal convoluted tubule Erythrocytes Bowman's capsule, parietal layer Distal convoluted tubule Collecting tubule Proximal convoluted tubule Proximal convoluted tubule </entry>
<entry linktype="AI" linkname="EUR-014-031" title="Figure 14.31: Medullary Cone, Kidney, Chicken">Medullary Cone, Kidney, Chicken. Various portions of uriniferous tubules (medullary type) are evident. Cells lining the thick ascending portions of Henle's loop show characteristic clear cytoplasmic blebs. A small portion of the cortex containing a proximal convoluted tubule can be seen on the upper right side. Thin segment, Henle's loop Thick ascending, Henle's loop Collecting duct Collecting duct Proximal convoluted tubule Thin segment, Henle's loop </entry>
<entry linktype="AI" linkname="EUR-014-032" title="Figure 14.32: Ureter, x.s., Chicken">Ureter, x.s., Chicken. The lamina propria is infiltrated with lymphocytes. Outer circular and inner longitudinal layers of the muscularis are distinguishable. The epithelium is pseudostratified columnar. Lymphatic tissue Muscularis, inner layer Muscularis, outer layer Pseudostratified epithelium Serosa Erythrocytes Erythrocytes </entry>
<entry linktype="AI" linkname="EUR-015-001" title="Figure 15.1: Nasal Cavity, Vestibule, Dog">Nasal Cavity, Vestibule, Dog. This portion of the vestibule is supported by hyaline cartilage and lined by a stratified squamous epithelium. Numerous cavernous veins occur throughout the connective tissue of the mucosa. In addition, there are tubular serous glands within the connective tissue. Cartilage Cavernous vein Cavernous vein Serous gland Stratified squamous epithelium </entry>
<entry linktype="AI" linkname="EUR-015-002" title="Figure 15.2: Portion of Nasal Concha, Dog">Portion of Nasal Concha, Dog. The scroll-like nasal conchae are supported by spongy bone and are covered by a mucous membrane with a ciliated, pseudostratified columnar epithelium. Nasal cavity Cavernous vein Cavernous vein Bone Pseudostratified epithelium </entry>
<entry linktype="AI" linkname="EUR-015-003" title="Figure 15.3: Olfactory Epithelium, Nasal Cavity, Dog (Masson's)">Olfactory Epithelium, Nasal Cavity, Dog (Masson's). This thick, pseudostratified columnar epithelium is composed of three types of cells. Basal cells are located at the level of the basement membrane. The nuclei of olfactory cells form a broad band in the central portion of the epithelium. The nuclei of supporting cells are pale and form the uppermost level of nuclei. The apices of olfactory cells bear sensory hairs. Bowman’s gland Cavernous vein Bowman’s gland Cavernous vein Basal cells Olfactory cells, nuclei Supporting cells, nuclei Sensory hairs </entry>
<entry linktype="AI" linkname="EUR-015-004" title="Figure 15.4: Respiratory Epithelium, Nasal Concha, Dog">Respiratory Epithelium, Nasal Concha, Dog. The ciliated, pseudostratified columnar epithelium with goblet cells and underlying, vascular, loose connective tissue and bone are shown. Goblet cell Cavernous vein Cavernous vein Bone Goblet cell </entry>
<entry linktype="AI" linkname="EUR-015-005" title="Figure 15.5: Lateral Nasal Gland, Dog (Masson's)">Lateral Nasal Gland, Dog (Masson's). This serous gland is located in the maxillary sinus in carnivores. Serous acinus Intercalated duct Intercalated duct Striated duct Serous acinus </entry>
<entry linktype="AI" linkname="EUR-015-006" title="Figure 15.6: Nasopharynx, Dog">Nasopharynx, Dog. This portion of the pharynx is lined by a ciliated, pseudostratified columnar epithelium with goblet cells. Mixed glands are present. The muscularis consists of skeletal muscle. Pseudostratified epithelium Duct Mixed gland Skeletal muscle </entry>
<entry linktype="AI" linkname="EUR-015-007" title="Figure 15.7: Epiglottis, Dog">Epiglottis, Dog. The supporting elastic cartilage of the epiglottis is heavily infiltrated in its mid-region by adipose tissue in carnivores. Lamina propria Stratified squamous epithelium, nonkeratinized Mixed gland Submucosa Elastic cartilage Adipose tissue </entry>
<entry linktype="AI" linkname="EUR-015-008" title="Figure 15.8: Epiglottis, l.s., Sheep">Epiglottis, l.s., Sheep. Blocklike chunks of elastic cartilage, without infiltrating adipose tissue, are found in the epiglottis of the sheep and goat. Elastic cartilage Stratified squamous epithelium, nonkeratinized Mixed gland </entry>
<entry linktype="AI" linkname="EUR-015-009" title="Figure 15.9: Epiglottis, Sheep">Epiglottis, Sheep. Occasionally, taste buds are found in the epithelium of the laryngeal surface of the epiglottis. Stratified squamous epithelium, nonkeratinized Taste bud </entry>
<entry linktype="AI" linkname="EUR-015-010" title="Figure 15.10: Glottis, x.s., Goat">Glottis, x.s., Goat. The glottis is supported by the arytenoid cartilages (elastic) and is lined by a nonkeratinized stratified squamous epithelium. Arytenoid cartilage Stratified squamous epithelium, nonkeratinized Arytenoid cartilage Mixed gland Adipose tissue </entry>
<entry linktype="AI" linkname="EUR-015-011" title="Figure 15.11: Vocal Fold, l.s., Cat">Vocal Fold, l.s., Cat. Junction of the vocal fold with the arytenoid cartilage. Arytenoid cartilage Stratified squamous epithelium Vocal ligament Stratified squamous epithelium </entry>
<entry linktype="AI" linkname="EUR-015-012" title="Figure 15.12: Vocal Fold, Goat (Orcein)">Vocal Fold, Goat (Orcein). The vocal fold consists of a fold of the mucous membrane. The vocal fold encloses the vocal ligament, which is a band of elastic fibers. Stratified squamous epithelium Elastic fibers Skeletal muscle </entry>
<entry linktype="AI" linkname="EUR-015-013" title="Figure 15.13: Trachea and Esophagus, x.s., Cat">Trachea and Esophagus, x.s., Cat. Note that the trachealis muscle (smooth) lies external to the gap in the C-shaped cartilage in carnivores. Hyaline cartilage Pseudostratified epithelium Trachea Adipose tissue Muscularis externa Esophagus Stratified squamous epithelium Trachealis muscle Mixed gland Hyaline cartilage </entry>
<entry linktype="AI" linkname="EUR-015-014" title="Figure 15.14: Trachea, x.s., Cat">Trachea, x.s., Cat. The trachea is lined by a ciliated, pseudostratified columnar epithelium with goblet cells. The lamina propria contains a band of longitudinally oriented elastic fibers. Goblet cell Pseudostratified epithelium Serous gland Lamina propria Submucosa Plasma cell Elastic fibers Plasma cell </entry>
<entry linktype="AI" linkname="EUR-015-015" title="Figure 15.15: Trachea, x.s., Horse">Trachea, x.s., Horse. A thick band of longitudinally arranged elastic fibers extends from the lamina propria into the submucosa. Serous gland Pseudostratified epithelium Elastic fibers Trachealis muscle Submucosa </entry>
<entry linktype="AI" linkname="EUR-015-016" title="Figure 15.16: Trachea, x.s., Cow">Trachea, x.s., Cow. In noncarnivores, the trachealis muscle attaches to the perichondrium on the inside of the tracheal cartilage. The lamina propria and submucosa are both very rich in elastic fibers. Trachealis muscle Pseudostratified epithelium Hyaline cartilage Perichondrium </entry>
<entry linktype="AI" linkname="EUR-015-017" title="Figure 15.17: Trachea, x.s., Cow">Trachea, x.s., Cow. The trachea is lined by a ciliated, pseudostratified columnar epithelium with goblet cells. Lamina propria Goblet cell </entry>
<entry linktype="AI" linkname="EUR-015-018" title="Figure 15.18: Trachea, x.s., Sheep (Orcein)">Trachea, x.s., Sheep (Orcein). A fibroelastic membrane surrounds the C-shaped tracheal cartilage and also spans the gap in the cartilage. Elastic fibers Pseudostratified epithelium Trachealis muscle Fibroelastic membrane Adipose tissue Elastic fibers Hyaline cartilage </entry>
<entry linktype="AI" linkname="EUR-015-019" title="Figure 15.19: Trachea, x.s., Goat (Orcein)">Trachea, x.s., Goat (Orcein). Numerous elastic fibers occur below the epithelium. Elastic fibers are also present where the trachealis muscle joins with the perichondrium. Trachealis muscle Tracheal glands Pseudostratified epithelium Elastic fibers Elastic fibers Elastic fibers Hyaline cartilage </entry>
<entry linktype="AI" linkname="EUR-015-020" title="Figure 15.20: Primary Bronchus, Extrapulmonary, x.s., Dog (Mallory's)">Primary Bronchus, Extrapulmonary, x.s., Dog (Mallory's). Plates of hyaline cartilage support the wall of the bronchus. Smooth muscle bundles of the muscularis occur between the plates and internal to them. Lamina propria Pseudostratified epithelium Muscularis Mixed glands Mixed glands Hyaline cartilage Hyaline cartilage </entry>
<entry linktype="AI" linkname="EUR-015-022" title="Figure 15.22: Bronchus, x.s., Cow">Bronchus, x.s., Cow. Detail of the wall of a bronchus. Numerous lymphocytes are present below the epithelium. Elastic band Pseudostratified epithelium Hyaline cartilage Lamina propria Muscularis Mixed gland </entry>
<entry linktype="AI" linkname="EUR-015-023" title="Figure 15.23: Small Bronchus, x.s., and Bronchioles, Cat">Small Bronchus, x.s., and Bronchioles, Cat. Bronchioles lack cartilaginous plates and possess a simple epithelium. Alveolus Alveolus Bronchiole Serous gland Alveolus Pseudostratified epithelium Lamina propria </entry>
<entry linktype="AI" linkname="EUR-015-024" title="Figure 15.24: Large Bronchiole, x.s., Cat">Large Bronchiole, x.s., Cat. In cats, submucosal serous glands extend from bronchi into the bronchioles. Bronchiole Serous gland Muscularis Columnar epithelium, ciliated Alveolus Serous gland Lymphatic nodule Alveolus </entry>
<entry linktype="AI" linkname="EUR-015-025" title="Figure 15.25: Large Bronchiole, x.s., Cat">Large Bronchiole, x.s., Cat. Detail of a portion of the bronchiole shown in Figure 15.24. Columnar epithelium, ciliated Goblet cell Serous gland Muscularis </entry>
<entry linktype="AI" linkname="EUR-015-026" title="Figure 15.26: Bronchioles, Pig (Orcein)">Bronchioles, Pig (Orcein). The tissues of the lung are heavily infiltrated with elastic fibers. Alveolus Bronchiole Muscularis Elastic fibers Elastic fibers Bronchiole </entry>
<entry linktype="AI" linkname="EUR-015-027" title="Figure 15.27: Respiratory Bronchiole, x.s., Cat">Respiratory Bronchiole, x.s., Cat. Respiratory bronchioles are lined by a cuboidal epithelium and have alveoli in their walls. Alveolus Respiratory bronchiole Cuboidal epithelium Smooth muscle Macrophage Alveolus Macrophage Alveolus </entry>
<entry linktype="AI" linkname="EUR-015-028" title="Figure 15.28: Respiratory Bronchiole, l.s., Sheep">Alveolar Ducts and Alveolar Sacs, Sheep. An alveolar duct is characterized by the presence of smooth muscle arranged circumferentially in the lips of the alveoli that form its wall. Conversely, the alveoli of alveolar sacs lack smooth muscle. Alveolus Alveolus Alveolus Smooth muscle Smooth muscle Cuboidal epithelium Respiratory bronchiole </entry>
<entry linktype="AI" linkname="EUR-015-029" title="Figure 15.29: Alveolar Ducts and Alveolar Sacs, Sheep">Alveolar Duct, x.s., Sheep. Detail of an alveolar duct. The smooth muscle associated with the entrance of the alveoli that form the wall of the duct is evident. Alveolus Bronchiole Smooth muscle Smooth muscle Smooth muscle Alveolus Alveolus Alveolar sac Alveolus Alveolar duct Alveolar duct </entry>
<entry linktype="AI" linkname="EUR-015-031" title="Figure 15.31: Alveoli, Cat">Visceral Pleura, Dog. The visceral pleura of carnivores is relatively thin. Alveolar septum Alveolus Type II alveolar cell Macrophage Alveolus Macrophage Alveolus Erythrocyte in capillary Type II alveolar cell Type II alveolar cell </entry>
<entry linktype="AI" linkname="EUR-015-032" title="Figure 15.32: Visceral Pleura, Dog">Visceral Pleura, Horse. The visceral pleura of domestic mammals, except carnivores, is thick. Incomplete septa extend inward from the visceral pleura in the horse. Alveolus Alveolus Macrophage Mesothelium Visceral pleura </entry>
<entry linktype="AI" linkname="EUR-015-033" title="Figure 15.33: Visceral Pleura, Horse">Visceral Pleura, Pig. Lungs are highly lobulated in the pig and ruminants. Unlike those of the horse, the septa are complete. Alveolus Alveolus Visceral pleura Elastic band Alveolus Septum Alveolus </entry>
<entry linktype="AI" linkname="EUR-015-034" title="Figure 15.34: Visceral Pleura, Pig">Visceral Pleura, Pig. Lungs are highly lobulated in the pig and ruminants. Unlike those of the horse, the septa are complete. Alveolus Bronchiole Visceral pleura Bronchiole Septum Bronchus Bronchus </entry>
<entry linktype="AI" linkname="EUR-015-035" title="Figure 15.35: Parietal Pleura, Cat">Parietal Pleura, Cat. Parietal pleura and intercostal muscle. The parietal pleura lines the wall of the pleural cavity. It consists of a mesothelium and underlying connective tissue. Intercostal muscle Intercostal muscle Neuromuscular spindle Parietal pleura </entry>
<entry linktype="AI" linkname="EUR-015-036" title="Figure 15.36: Lung, Cow (Masson's)">Lung, Cow (Masson's). In the cow and pig, pulmonary veins have thick bands of circularly arranged smooth muscle. Alveolus Alveolus Pulmonary vein Smooth muscle Smooth muscle Septum </entry>
<entry linktype="AI" linkname="EUR-015-037" title="Figure 15.37: Nasal Cavity, Chicken">Nasal Cavity, Chicken. The vestibule is lined by a uniquely structured, keratinized, stratified squamous epithelium (see Figure 15.38). The vestibular epithelium blends with the epidermis on the inner side of each nostril. In this micrograph, these epithelia lie to either side of a turbinate cartilage. Epidermis Parietal pleura Lamina propria Pseudostratified epithelium </entry>
<entry linktype="AI" linkname="EUR-015-038" title="Figure 15.38: Vestibular Epithelium, Chicken">Vestibular Epithelium, Chicken. This keratinized, stratified squamous epithelium is characterized by the presence of columns of cells. The uppermost cells in each column have pyknotic nuclei. One or two layers of basal cells are present. The outer surface of the epithelium presents a corrugated appearance. Pyknotic nucleus Pyknotic nucleus Lamina propria Basal cells </entry>
<entry linktype="AI" linkname="EUR-015-039" title="Figure 15.39: Respiratory Epithelium, Chicken (Masson's)">Respiratory Epithelium, Chicken (Masson's). This ciliated, pseudostratified columnar epithelium is interrupted by simple, branched, alveolar mucous glands. Mucous gland Lamina propria Nerve, unmyelinated Pseudostratified epithelium </entry>
<entry linktype="AI" linkname="EUR-015-040" title="Figure 15.40: Olfactory Epithelium, Chicken (Masson's)">Olfactory Epithelium, Chicken (Masson's). This pseudostratified columnar epithelium is similar to that found in mammals (see Figure 15.3). It is composed of basal, olfactory, and supporting cells. Supporting cell, nucleus Supporting cell, nucleus Olfactory cells, nuclei Basal cell Bowman's gland Nerve, unmyelinated </entry>
<entry linktype="AI" linkname="EUR-015-041" title="Figure 15.41: Trachea, l.s., Chicken">Trachea, l.s., Chicken. Cartilaginous tracheal rings are complete and overlap each other. When the trachea is cut longitudinally, as in this preparation, the rings are cut transversely and present a lenticular profile. Pseudostratified epithelium Cartilaginous tracheal ring Skeletal muscle Skeletal muscle </entry>
<entry linktype="AI" linkname="EUR-015-042" title="Figure 15.42: Trachea, x.s., Chicken">Trachea, x.s., Chicken. Simple alveolar mucous glands occur in the ciliated, pseudostratified columnar epithelium. Portions of two overlapping tracheal rings are present. The inner ring was cut through its thin edge, while the outer one was cut through its thick middle region. See Figure 15.41 for an example of the shape of a tracheal ring that has been cut transversely. Pseudostratified epithelium Mucous gland Cartilaginous tracheal ring Cartilaginous tracheal ring Skeletal muscle </entry>
<entry linktype="AI" linkname="EUR-015-043" title="Figure 15.43: Trachea, x.s., Chicken">Trachea, x.s., Chicken. Intraepithelial mucous glands are abundant in the trachea of the chicken. Also see Figure 15.39. Mucous gland Pseudostratified epithelium Cartilaginous tracheal ring Cartilaginous tracheal ring </entry>
<entry linktype="AI" linkname="EUR-015-044" title="Figure 15.44: Trachea, Near Syrinx, Chicken">Trachea, Near Syrinx, Chicken. The majority of the posterior, complete rings of the trachea shown here are bony. The ciliated pseudostratified columnar epithelium of the trachea is followed in the syrinx by a stratified squamous epithelium. Pseudostratified epithelium Stratified squamous epithelium Bony tracheal ring Cartilaginous tracheal ring </entry>
<entry linktype="AI" linkname="EUR-015-045" title="Figure 15.45: Trachea, Syrinx, and Primary Bronchi, l.s., Chicken">Trachea, Syrinx, and Primary Bronchi, l.s., Chicken. As this drawing indicates, the syrinx is an upside-down-Y-shaped structure positioned between the trachea and the primary bronchi. Two pairs of thin membranes, the external and internal tympanic membranes, produce sound. The syrinx is supported by cartilages and a wedge-shaped cartilaginous or bony pessulus. Bony tracheal ring Cartilaginous tracheal rings Intermediate syringeal cartilage Pessulus External tympanic membrane Internal tympanic membrane Bronchial rings Medial bronchial wall </entry>
<entry linktype="AI" linkname="EUR-015-046" title="Figure 15.46: Syrinx, l.s., Chicken">Syrinx, l.s., Chicken. The external and internal tympanic membranes of the syrinx, as well as the bony pessulus and an intermediate syringeal cartilage, are shown. Intermediate syringeal cartilage Pessulus External tympanic membrane Internal tympanic membrane </entry>
<entry linktype="AI" linkname="EUR-015-047" title="Figure 15.47: Syrinx, l.s., Chicken">Syrinx, l.s., Chicken. A portion of the external tympanic membrane and intermediate syringeal cartilage. Intermediate syringeal cartilage Stratified squamous epithelium External tympanic membrane </entry>
<entry linktype="AI" linkname="EUR-015-049" title="Figure 15.49: Syrinx, l.s., Chicken">Syrinx, l.s., Chicken. Portion of pessulus and internal tympanic membrane. The latter is covered by both a ciliated, stratified columnar epithelium and by a stratified squamous epithelium. Stratified columnar epithelium Stratified columnar epithelium Stratified squamous epithelium Pessulus </entry>
<entry linktype="AI" linkname="EUR-015-050" title="Figure 15.50: Tympanic Membrane and Primary Bronchus, Chicken">Tympanic Membrane and Primary Bronchus, Chicken. Three transected bronchial cartilages. Bronchial cartilages are incomplete (C-shaped). They do not extend to the medial side of the bronchus. Internal tympanic membrane Syrinx External tympanic membrane Bronchial cartilage Pseudostratified epithelium Primary bronchus Pseudostratified epithelium </entry>
<entry linktype="AI" linkname="EUR-015-051" title="Figure 15.51: Lung, Chicken">Lung, Chicken. Longitudinal section through a secondary bronchus and parabronchi. The presence of numerous cup-shaped atria in the parabronchus distinguish this part of the bronchial tree from the secondary bronchus. Secondary bronchus Lymphatic tissue Smooth muscle Smooth muscle Parabronchus Atrium Parabronchus Smooth muscle Atrium </entry>
<entry linktype="AI" linkname="EUR-015-052" title="Figure 15.52: Lung, Chicken">Lung, Chicken. Cross section of a parabronchus and a portion of an adjacent secondary bronchus. Secondary bronchus Smooth muscle Mucous cells Air capillary Air capillary Air capillary Parabronchus Atrium Smooth muscle Atrium Air capillary </entry>
<entry linktype="AI" linkname="EUR-015-053" title="Figure 15.53: Lung, Chicken">Lung, Chicken. Detail of the wall of a parabronchus. Note the continuity of the air capillaries with the atria. The latter are lined by an epithelium that varies from simple cuboidal to simple squamous. Macrophage Smooth muscle Smooth muscle Macrophage Atrium Air capillary Air capillary Erythrocytes in vascular capillary Erythrocytes in vascular capillary Air capillary Erythrocytes in vascular capillary Granulocyte Air capillary </entry>
<entry linktype="AI" linkname="EUR-015-054" title="Figure 15.54: Abdominal Air Sac, Chicken">Abdominal Air Sac, Chicken. The wall of the air sac consists of a connective tissue lamina and an epithelium that may be simple squamous, cuboidal, or ciliated columnar. Air sacs are not well vascularized. Epithelium Epithelium Epithelium Connective tissue lamina </entry>
<entry linktype="AI" linkname="EUR-015-055" title="Figure 15.55: Humerus, x.s., Chicken (Masson's)">Humerus, x.s., Chicken (Masson's). Many bones of the chicken contain extensions of air sacs. Bone Connective tissue lamina Cavity of air sac Simple squamous epithelium Bone Bone </entry>
<entry linktype="AI" linkname="EUR-016-001" title="Figure 16.1: Pituitary Gland, Cat">Pituitary Gland, Cat. Parasagittal section showing all major components. In domestic mammals, except the horse, the cavity of Rathke's pouch persists in the adult. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Median eminence Pars tuberalis Infundibular stalk Infundibular cavity Pars distalis Pars nervosa Pars intermedia Cavity of RathkeΓÇÖs pouch Pars tuberalis </entry>
<entry linktype="AI" linkname="EUR-016-002" title="Figure 16.2: Pituitary Gland, Cat">Pituitary Gland, Cat. Detail of the infundibular stalk and pars tuberalis. Note the presence of small follicles in the pars tuberalis lined by faintly basophilic epithelial cells. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Follicle Ependymal cells Infundibular cavity Infundibular stalk Infundibular stalk Pars tuberalis Pars tuberalis </entry>
<entry linktype="AI" linkname="EUR-016-003" title="Figure 16.3: Pituitary Gland, Cat">Pituitary Gland, Cat. Pars intermedia, pars distalis, and pars nervosa. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Pars distalis Cavity of Rathke’s pouch Pars intermedia Pars nervosa </entry>
<entry linktype="AI" linkname="EUR-016-004" title="Figure 16.4: Pituitary Gland, Dog">Pituitary Gland, Dog. Detail of the pars distalis, pars intermedia, and pars nervosa. Acidophils Chromophobes Pars nervosa Pars intermedia Pars distalis Acidophils Blood vessel Cavity of Rathke’s pouch </entry>
<entry linktype="AI" linkname="EUR-016-005" title="Figure 16.5: Pituitary Gland, Parasagittal Section, Horse">Pituitary Gland, Parasagittal Section, Horse. Although present in other domestic animals, the cavity of Rathke's pouch is lacking in the horse. Infundibular cavity Pars tuberalis Pars distalis Pars intermedia Pars nervosa </entry>
<entry linktype="AI" linkname="EUR-016-006" title="Figure 16.6: Pituitary Gland, Horse (Alcian Blue, Orange G, Schiff's Reagent)">Pituitary Gland, Horse (Alcian Blue, Orange G, Schiff's Reagent). Pars distalis, pars intermedia, and pars nervosa. Note the presence of follicles in the pars intermedia. Pars distalis Pars intermedia Pars nervosa Follicle Follicle </entry>
<entry linktype="AI" linkname="EUR-016-007" title="Figure 16.7: Pituitary Gland, Horse (Alcian Blue, Orange G, Schiff's Reagent)">Pituitary Gland, Horse (Alcian Blue, Orange G, Schiff's Reagent). Detail of the pars intermedia and pars nervosa. The latter has a distinctive fibrous appearance. Pars intermedia Pars nervosa Blood vessel </entry>
<entry linktype="AI" linkname="EUR-016-008" title="Figure 16.8: Pituitary Gland, Horse (Alcian Blue, Orange G, Schiff's Reagent)">Pituitary Gland, Horse (Alcian Blue, Orange G, Schiff's Reagent). Detail of the pars distalis. In this preparation, acidophils are orange, whereas basophils vary from blue to red. Chromophobes are small and pale. Chromophobes Sinusoid Basophil Basophil Acidophil Chromophobes Sinusoid Acidophil Basophil </entry>
<entry linktype="AI" linkname="EUR-016-009" title="Figure 16.9: Pituitary Gland, Horse">Pituitary Gland, Horse. Detail of the pars distalis. Chromophobes appear in clusters and have closely spaced nuclei. Chromophobes Chromophobes Acidophil Basophil Basophil Acidophil </entry>
<entry linktype="AI" linkname="EUR-016-010" title="Figure 16.10: Pituitary Gland, Horse">Pituitary Gland, Horse. A portion of the infundibular stalk, pars distalis, and pars tuberalis. Pars distalis Infundibular stalk Infundibular cavity Infundibular stalk Pars tuberalis </entry>
<entry linktype="AI" linkname="EUR-016-011" title="Figure 16.11: Pineal Gland, Dog">Pineal Gland, Dog. This gland consists primarily of pinealocytes and is located in the midline of the epithalamus. Pineal stalk Pineal stalk </entry>
<entry linktype="AI" linkname="EUR-016-012" title="Figure 16.12: Pineal Gland, Dog">Pineal Gland, Dog. Detail of the gland. Pinealocytes Follicle, tangential cut Fibers of neuroglial cells Fibers of neuroglial cells Pinealocytes Pinealocytes Fibers of neuroglial cells </entry>
<entry linktype="AI" linkname="EUR-016-013" title="Figure 16.13: Thyroid and Parathyroid Glands, Dog">Thyroid and Parathyroid Glands, Dog. The basophilic, highly cellular parathyroid gland contrasts with the numerous colloid-filled follicles of the thyroid gland. Adipose tissue Pineal gland Follicle, tangential cut Follicle, tangential cut </entry>
<entry linktype="AI" linkname="EUR-016-014" title="Figure 16.14: Thyroid Gland, Inactive, Dog">Thyroid Gland, Inactive, Dog. Parafollicular cells (C-cells) have pale-staining cytoplasm. In the dog they are particularly numerous and frequently occur in groups. Parathyroid gland Parathyroid gland Parathyroid gland Parathyroid gland Follicular cell Follicular cell Parafollicular cell Colloid Parafollicular cell Parathyroid gland </entry>
<entry linktype="AI" linkname="EUR-016-015" title="Figure 16.15: Thyroid Gland, Inactive, Dog">Thyroid Gland, Inactive, Dog. Large, pale-staining parafollicular cells often form a part of the cellular lining of a thyroid follicle. Parafollicular cell Parafollicular cells Colloid Parafollicular cells Parafollicular cell Parafollicular cells </entry>
<entry linktype="AI" linkname="EUR-016-016" title="Figure 16.16: Thyroid Gland, Active, Horse">Thyroid Gland, Active, Horse. Active thyroid follicles are characterized by tall follicular cells and vacuolated colloid. Compare with Figures 16.15 and 16.17. Follicular cell Colloid Space artifact </entry>
<entry linktype="AI" linkname="EUR-016-017" title="Figure 16.17: Thyroid Gland, Inactive, Goat">Thyroid Gland, Inactive, Goat. The high degree of vascularity of the thyroid gland is well illustrated in this micrograph. Pigment granules accumulate in the follicle cells of older animals. Colloid Space artifact Erythrocytes in sinusoid Follicular cell, pigmented Follicular cell, pigmented Erythrocytes in sinusoid Follicular cell, pigmented </entry>
<entry linktype="AI" linkname="EUR-016-018" title="Figure 16.18: Parathyroid Gland, Dog">Parathyroid Gland, Dog. Cysts containing colloid frequently occur in the parathyroid gland. Such cysts are lined by a ciliated columnar epithelium. Principal cells Cyst Principal cells Cilia Space artifact </entry>
<entry linktype="AI" linkname="EUR-016-019" title="Figure 16.19: Parathyroid Gland, Dog">Parathyroid Gland, Dog. Both light and dark principal cells are visible. The active, dark cells have a nucleus with condensed chromatin and a dark, acidophilic cytoplasm. The inactive, light cells have a larger and paler nucleus and a lighter, acidophilic cytoplasm. Light cell Light cell Dark cell Dark cell </entry>
<entry linktype="AI" linkname="EUR-016-020" title="Figure 16.20: Parathyroid Gland, Cow">Parathyroid Gland, Cow. The stroma of connective tissue of the parathyroid gland of cows and pigs is abundant. Stroma Stroma Principal cells Principal cells Stroma </entry>
<entry linktype="AI" linkname="EUR-016-021" title="Figure 16.21: Adrenal Gland, Dog">Adrenal Gland, Dog. Adrenal cortex and capsule. The cells of the zona glomerulosa are arranged into arclike formations in carnivores, horses, and pigs. Capsule Zona glomerulosa Zona intermedia Zona fasciculata Sinusoid Zona reticularis, cells of Sinusoid </entry>
<entry linktype="AI" linkname="EUR-016-022" title="Figure 16.22: Adrenal Gland, Cat">Adrenal Gland, Cat. Detail of a portion of the cortex. A zona intermedia occurs between the zona glomerulosa and zona fasciculata. It is especially well developed in carnivores and horses. It consists of small, polyhedral cells. Cells of the zona fasciculata are characteristically highly vacuolated. Capsule Zona glomerulosa Zona intermedia Sinusoid Zona fasciculata Sinusoid </entry>
<entry linktype="AI" linkname="EUR-016-023" title="Figure 16.23: Adrenal Gland, Horse">Adrenal Gland, Horse. Adrenal cortex and capsule. The zona glomerulosa consists of high arcs composed of especially tall epithelial cells in the horse. Clusters of epithelioid cortical cells frequently occur in the capsule of the adrenal gland. A distinct intermediate zone separates the zona glomerulosa from the zona fasciculata. Capsule Epithelioid cells Zona glomerulosa Zona intermedia Zona fasciculata </entry>
<entry linktype="AI" linkname="EUR-016-024" title="Figure 16.24: Adrenal Gland, Horse">Adrenal Gland, Horse. An autonomic ganglion, partly surrounded by cells extending from the zona reticularis, is situated in the medulla. Medulla Ganglion cell Zona reticularis, cells of Zona reticularis, cells of Medulla </entry>
<entry linktype="AI" linkname="EUR-016-025" title="Figure 16.25: Adrenal Gland, Cow">Adrenal Gland, Cow. Portions of the cortex and medulla. The medulla is subdivided into an outer region of darkly stained cells and an inner portion of lightly stained cells. Capsule Zona glomerulosa Zona fasciculata Zona reticularis, cells of Medulla, outer region Medulla, inner region </entry>
<entry linktype="AI" linkname="EUR-016-026" title="Figure 16.26: Adrenal Gland, Cow">Adrenal Gland, Cow. Portion of the adrenal cortex. The cells of the zona glomerulosa are arranged into irregular groups and cords in ruminants. Compare with Figures 16.21, 16.22, and 16.23. Capsule Zona glomerulosa Zona intermedia Zona intermedia Zona intermedia Zona fasciculata </entry>
<entry linktype="AI" linkname="EUR-016-027" title="Figure 16.27: Adrenal Gland, Cow">Adrenal Gland, Cow. The basophilic cells of the outer region of the adrenal medulla contrast with the paler cells of the inner region. Zona reticularis Medulla, outer region Medulla, inner region </entry>
<entry linktype="AI" linkname="EUR-016-028" title="Figure 16.28: Adrenal Gland, Sheep (Masson's)">Adrenal Gland, Sheep (Masson's). Adrenal medulla with ganglion cells and cells of the zona reticularis amid the chromaffin cells. Chromaffin cells Zona reticularis Chromaffin cells Zona reticularis Ganglion cell </entry>
<entry linktype="AI" linkname="EUR-016-029" title="Figure 16.29: Pituitary Gland, Parasagittal Section, Chicken">Pituitary Gland, Parasagittal Section, Chicken. In the chicken, the pars distalis is divisible into a cephalic zone and a caudal zone. The cephalic zone is more basophilic. Ciliated cysts commonly occur within the pars distalis. See Figure 16.32 for detail of a cyst. Pars tuberalis Diencephalon Pars distalis, cephalic Pars tuberalis Infundibular cavity Infundibular stalk Cyst Skull Pars nervosa Pars distalis, caudal </entry>
<entry linktype="AI" linkname="EUR-016-030" title="Figure 16.30: Pituitary Gland, Chicken">Pituitary Gland, Chicken. The cephalic zone of the pars distalis consists of closely packed cords of chromophils and chromophobes. Some cords have a lumen filled with colloid. Sinusoid, with erythrocytes Chromophils Colloid Chromophobes Chromophils Colloid Sinusoid, with erythrocytes Chromophobes </entry>
<entry linktype="AI" linkname="EUR-016-031" title="Figure 16.31: Pituitary Gland, Chicken">Pituitary Gland, Chicken. In the caudal zone of the pars distalis, the cells of the cords are more loosely arranged than those of the cephalic zone. Acidophils have a more intensely stained cytoplasm than those of the cephalic zone, and they can be readily distinguished from basophils. Basophil Granulocytes Basophil Acidophil Sinusoid Acidophil Sinusoid </entry>
<entry linktype="AI" linkname="EUR-016-032" title="Figure 16.32: Pituitary Gland, Chicken">Pituitary Gland, Chicken. Portion of a cyst, in the pars distalis, lined by ciliated cells and mucous cells. Ciliated cell Mucous cell </entry>
<entry linktype="AI" linkname="EUR-016-033" title="Figure 16.33: Pituitary Gland, Chicken">Pituitary Gland, Chicken. Portions of the pars tuberalis and adjacent infundibular stalk. The cells of the pars tuberalis are rounded to elongated with a finely granular, slightly basophilic cytoplasm and a round to oval nucleus. Infundibular stalk Pars tuberalis Pars tuberalis </entry>
<entry linktype="AI" linkname="EUR-016-034" title="Figure 16.34: Pituitary Gland, Chicken">Pituitary Gland, Chicken. A group of pituicytes within the pars nervosa. Pituicytes have a clear cytoplasm and a large, vesicular nucleus. Pituicyte Pituicyte Pars distalis, caudal </entry>
<entry linktype="AI" linkname="EUR-016-035" title="Figure 16.35: Pineal Gland, Parasagittal Section, Chicken">Pineal Gland, Parasagittal Section, Chicken. The body of the pineal gland, portion of the overlying skull, and the cerebellum. Skull Capsule Pineal gland Cerebellum </entry>
<entry linktype="AI" linkname="EUR-016-036" title="Figure 16.36: Pineal Gland, Chicken">Pineal Gland, Chicken. The parenchymal cells of the pineal gland are arranged as compact masses (rosettes) or as round to oval follicles with distinct lumens. Rosette Follicle Rosette Follicle Rosette </entry>
<entry linktype="AI" linkname="EUR-016-037" title="Figure 16.37: Parathyroid Gland, Chicken">Parathyroid Gland, Chicken. This gland consists of chief cells arranged into a feltwork of anastomosing cords. The cords are surrounded by strands of connective tissue and numerous sinusoids. Adipose tissue Capsule Chief cells Chief cells Sinusoid Sinusoid Chief cells </entry>
<entry linktype="AI" linkname="EUR-016-038" title="Figure 16.38: Adrenal Gland, Chicken">Adrenal Gland, Chicken. Cords of cortical cells are interwoven between clumps and irregular masses of medullary cells throughout the gland. Capsule Ganglion Capsule Cortical cells Medullary cells Cortical cells Medullary cells </entry>
<entry linktype="AI" linkname="EUR-016-039" title="Figure 16.39: Adrenal Gland, Chicken">Adrenal Gland, Chicken. Detail of cortical and medullary cells. Cortical cells are columnar. When longitudinal cuts have been made through cords of cortical cells, the cells form a bilayer. When cords are cut transversely, the cells are seen to be arranged radially. Medullary cells are polygonal, are larger than cortical cells, and possess basophilic cytoplasm. They are arranged as clumps or irregular masses. Medullary cells Sinusoid Cortical cells Cortical cells Medullary cells </entry>
<entry linktype="AI" linkname="EUR-017-001" title="Figure 17.1: Testis, x.s., Baby Boar">Testis, x.s., Baby Boar. Developing sex cords in the testis of a two-day-old boar. Sex cord Straight tubule Rete testis Straight tubule Sex cord </entry>
<entry linktype="AI" linkname="EUR-017-002" title="Figure 17.2: Testis, x.s., Baby Boar">Testis, x.s., Baby Boar. Detail of developing sex cords and interstitial cells. Two types of cells can be distinguished in the sex cord. Supporting cells (small with dark nuclei) are positioned along the edges of the cords. They will develop into Sertoli cells. Gonocytes, precursors of spermatogonia, are located in the interior of the cords. They have large, pale nuclei. Interstitial cells Supporting cells Gonocyte Gonocyte Interstitial cells Supporting cells Gonocyte Interstitial cells Straight tubule </entry>
<entry linktype="AI" linkname="EUR-017-003" title="Figure 17.3: Testis, Stallion (Mallory's)">Testis, Stallion (Mallory's). The tunica albuginea of the stallion is characterized by the presence of smooth muscle. Tunica vaginalis Tunica albuginea, smooth muscle Tunica albuginea, vascular layer Tunica albuginea, vascular layer Interstitial cells Seminiferous tubule Seminiferous tubule Interstitial cells </entry>
<entry linktype="AI" linkname="EUR-017-004" title="Figure 17.4: Testis, Boar (Mallory's)">Testis, Boar (Mallory's). The tunica albuginea consists of dense irregular connective tissue. It lacks smooth muscle in domestic mammals, except the stallion. Tunica vaginalis Tunica albuginea, vascular layer Tunica albuginea Interstitial cells Seminiferous tubule </entry>
<entry linktype="AI" linkname="EUR-017-005" title="Figure 17.5: Seminiferous Tubules, Testis, Dog">Seminiferous Tubules, Testis, Dog. A portion of each of three adjacent seminiferous tubules is shown . Lumen Spermatid, early Sertoli cell, nucleus Primary spermatocyte Primary spermatocyte Myoid cell, nucleus Sertoli cell, nucleus Primary spermatocyte Myoid cell, nucleus Sertoli cell, nucleus Spermatogonia Spermatid, early Sertoli cell, nucleus Spermatid, late Primary spermatocyte Lumen Spermatid, late </entry>
<entry linktype="AI" linkname="EUR-017-006" title="Figure 17.6: Seminiferous Tubules, Testis, Stallion">Seminiferous Tubules, Testis, Stallion. Portions of four seminiferous tubules are visible. Note the numerous interstitial cells (abundant in the boar and stallion) and the section through a straight tubule. Interstitial cell Spermatogonium Spermatid, late Primary spermatocyte Spermatogonium Spermatid, late Sertoli cell, nucleus Primary spermatocyte Interstitial cell Primary spermatocyte Straight tubule Spermatid, early Sertoli cell, nucleus Interstitial cell Sertoli cell, nucleus Myoid cell, nucleus Spermatid, early Myoid cell, nucleus </entry>
<entry linktype="AI" linkname="EUR-017-007" title="Figure 17.7: Interstitial Tissue, Testis, Ram">Interstitial Tissue, Testis, Ram. Interstitial tissue and portions of three seminiferous tubules are shown. Interstitial cells are relatively sparse in carnivores and ruminants. Interstitial cell Sertoli cell, nucleus Primary spermatocyte Spermatid, early Interstitial cell Spermatogonium Sertoli cell, nucleus Myoid cell, nucleus </entry>
<entry linktype="AI" linkname="EUR-017-008" title="Figure 17.8: Transitional Zone and Straight Tubule, Testis, Stallion">Transitional Zone and Straight Tubule, Testis, Stallion. A transitional zone joins a seminiferous tubule to a straight tubule. Sertoli cells line this zone and protrude into the lumen of the straight tubule. Straight tubule Sertoli cells Transitional zone Sertoli cells </entry>
<entry linktype="AI" linkname="EUR-017-009" title="Figure 17.9: Rete Testis, Stallion">Rete Testis, Stallion. Anastomosing channels of the rete testis lie within the loose connective tissue of the mediastinum testis. In the stallion, the rete testis extends through the tunica albuginea and becomes extratesticular, as in this micrograph. Junctions of rete channels and efferent ductules can be seen. See Figure 17.10 for a magnified view of a junction . Mediastinum testis Rete testis, channel Efferent ductule Rete testis, channel Efferent ductule Efferent ductule Rete testis, channel Seminiferous tubules Tunica albuginea </entry>
<entry linktype="AI" linkname="EUR-017-010" title="Figure 17.10: Junction of Rete Testis and Efferent Ductule, Stallion">Junction of Rete Testis and Efferent Ductule, Stallion. The rete testis is lined by cuboidal cells, whereas the efferent ductule is lined by a ciliated, pseudostratified columnar epithelium. Pseudostratified epithelium, efferent ductule Spermatozoa Cuboidal epithelium, rete testis </entry>
<entry linktype="AI" linkname="EUR-017-011" title="Figure 17.11: Efferent Ductules, Stallion">Efferent Ductules, Stallion. Various cuts through the tortuous efferent ductules are surrounded by loose connective tissue. Efferent ductule Loose connective tissue Efferent ductule Loose connective tissue </entry>
<entry linktype="AI" linkname="EUR-017-012" title="Figure 17.12: Efferent Ductules, Stallion">Efferent Ductules, Stallion. Efferent ductules are lined by a ciliated, pseudostratified columnar epithelium. However, the epithelium may be simple columnar in some places. Pseudostratified epithelium Spermatozoa Columnar epithelium </entry>
<entry linktype="AI" linkname="EUR-017-013" title="Figure 17.13: Head of Epididymis, Stallion (Masson's)">Head of Epididymis, Stallion (Masson's). The epididymis is surrounded by a tunica albuginea of dense, irregular connective tissue, which contains smooth muscle in the stallion. Portions of the coiled duct of the epididymis are shown. Tunica vaginalis, mesothelium Tunica albuginea, smooth muscle Duct of the epididymis Loose connective tissue Duct of the epididymis </entry>
<entry linktype="AI" linkname="EUR-017-014" title="Figure 17.14: Head of Epididymis, Stallion">Head of Epididymis, Stallion. In this region the pseudostratified columnar epithelium of the duct of the epididymis is thickest. Smooth muscle is scarce. Compare with Figures 17.15 and 17.16. Loose connective tissue Lymphocyte, migrating Smooth muscle Lymphocyte, migrating Pseudostratified epithelium </entry>
<entry linktype="AI" linkname="EUR-017-015" title="Figure 17.15: Body of Epididymis, Stallion">Body of Epididymis, Stallion. The duct of the epididymis in this region is surrounded by more smooth muscle than in the head of the epididymis, and the pseudostratified columnar epithelium is not as thick as in the head of the epididymis (see Figure 17.14). Smooth muscle Loose connective tissue Pseudostratified epithelium Spermatozoa Pseudostratified epithelium Smooth muscle </entry>
<entry linktype="AI" linkname="EUR-017-016" title="Figure 17.16: Tail of Epididymis, Stallion">Tail of Epididymis, Stallion. A low, pseudostratified columnar epithelium and abundant circular smooth muscle characterize the duct of the epididymis in this region. In the stallion, the caudal segment of the duct of the epididymis has villuslike projections. Spermatozoa Villus-like projection Loose connective tissue Smooth muscle Pseudostratified epithelium </entry>
<entry linktype="AI" linkname="EUR-017-017" title="Figure 17.17: Tail of Epididymis, Stallion">Tail of Epididymis, Stallion. Detail of the duct of the epididymis lined by low, pseudostratified columnar epithelium and surrounded by abundant, circular smooth muscle. Spermatozoa Stereocilia Pseudostratified epithelium Basal cell Smooth muscle </entry>
<entry linktype="AI" linkname="EUR-017-018" title="Figure 17.18: Vas Deferens, x.s., Dog">Vas Deferens, x.s., Dog. The bulk of the wall consists of smooth muscle, which forms an inner circular and an outer predominantly longitudinal layer with some randomly arranged cells. Pseudostratified epithelium Muscularis Serosa </entry>
<entry linktype="AI" linkname="EUR-017-019" title="Figure 17.19: Vas Deferens, x.s., Stallion (Masson's)">Vas Deferens, x.s., Stallion (Masson's). This section of the vas deferens, taken from near the epididymis, has long mucosal folds. The inner layer of the muscularis contains interwoven bundles of smooth muscle. Although out of the field of view in this micrograph, the smooth muscle of the outer layer of the muscularis is mostly arranged longitudinally. Pseudostratified epithelium Lamina propria Lamina propria Muscularis </entry>
<entry linktype="AI" linkname="EUR-017-020" title="Figure 17.20: Vas Deferens, x.s., Boar (Masson's)">Vas Deferens, x.s., Boar (Masson's). The muscularis consists of an admixture of longitudinally and randomly arranged smooth muscle. The epithelium is pseudostratified columnar with stereocilia present intermittently. Pseudostratified epithelium Lamina propria Muscularis Serosa </entry>
<entry linktype="AI" linkname="EUR-017-021" title="Figure 17.21: Ampulla, x.s., Ram">Ampulla, x.s., Ram. The terminal segment of the vas deferens, the ampulla, contains branched tubuloalveolar glands in the dog, stallion, and ruminants. The glands are poorly developed in the boar. The ampulla is absent in the tomcat. Ampulla, lumen Pseudostratified epithelium Gland Muscularis Adventitia </entry>
<entry linktype="AI" linkname="EUR-017-022" title="Figure 17.22: Ampulla, Ram">Ampulla, Ram. Detail of the mucosa. Spermatozoa are stored in the glands close to their openings into the lumen of the ampulla. Secretion Secretion Pseudostratified epithelium Spermatozoa Pseudostratified epithelium Ampulla, lumen </entry>
<entry linktype="AI" linkname="EUR-017-023" title="Figure 17.23: Ampulla, Ram">Ampulla, Ram. The secretory alveoli are lined by a pseudostratified epithelium composed of cuboidal to columnar cells and occasional basal cells. Secretion Basal cell, nucleus Basal cell, nucleus Secretion </entry>
<entry linktype="AI" linkname="EUR-017-024" title="Figure 17.24: Seminal Vesicle, Castrated Billy Goat">Seminal Vesicle, Castrated Billy Goat. In the castrated male, the glandular tissue of the accessory glands is greatly reduced. Compare with Figure 17.25. Interlobular septum Gland </entry>
<entry linktype="AI" linkname="EUR-017-025" title="Figure 17.25: Seminal Vesicle, Ram">Seminal Vesicle, Ram. Lobules of tubuloalveolar glands are divided by interlobular septa, which contain an abundance of smooth muscle in ruminants. In the stallion and boar, the septa consist predominantly of connective tissue with some smooth muscle. Seminal vesicles are absent in carnivores. Interlobular septum Gland </entry>
<entry linktype="AI" linkname="EUR-017-026" title="Figure 17.25: Seminal Vesicle, Ram">Seminal Vesicle, Ram. The pseudostratified glandular epithelium is characterized by sparse basal cells. Note the muscular septum. Basal cell Interlobular septum Basal cell </entry>
<entry linktype="AI" linkname="EUR-017-027" title="Figure 17.27: Body of the Prostate, Dog">Body of the Prostate, Dog. The body of the prostate, which is well developed in carnivores and the stallion, is surrounded by a capsule of dense connective tissue and smooth muscle. Trabeculae from the capsule divide the gland into lobules. Capsule Trabecula Trabecula Gland </entry>
<entry linktype="AI" linkname="EUR-017-028" title="Figure 17.28: Body of the Prostate, Dog">Body of the Prostate, Dog. In the dog, this is a serous gland. Compare with Figure 17.31. Pseudostratified epithelium Secretion Secretion </entry>
<entry linktype="AI" linkname="EUR-017-029" title="Figure 17.29: Disseminate Portion of the Prostate, x.s., Ram (Masson's)">Disseminate Portion of the Prostate, x.s., Ram (Masson's). This portion of the prostate is well developed in the boar and ruminants. The glands are located within the submucosa of the pelvic urethra. The stratum cavernosum of the pelvic urethra contains cavernous spaces that are smaller and less numerous than those of the corpus spongiosum of the penile urethra. Transitional epithelium Urethra, lumen Duct Stratum cavernosum Prostate gland </entry>
<entry linktype="AI" linkname="EUR-017-030" title="Figure 17.30: Disseminate Portion of the Prostate, x.s., Ram (Masson's)">Disseminate Portion of the Prostate, x.s., Ram (Masson's). The transitional epithelium of both the pelvic urethra and a duct of the prostate gland is shown. Urethra, lumen Transitional epithelium Lamina propria Duct </entry>
<entry linktype="AI" linkname="EUR-017-031" title="Figure 17.31: Disseminate Portion of the Prostate, x.s., Ram (Masson's)">Disseminate Portion of the Prostate, x.s., Ram (Masson's). The prostate is a mixed gland except in the dog, where there are no mucous secretory units. Mucous cells Smooth muscle Smooth muscle </entry>
<entry linktype="AI" linkname="EUR-017-032" title="Figure 17.32: Bulbourethral Gland, Boar">Bulbourethral Gland, Boar. This gland is a compound tubular gland in the boar, tomcat, and billy goat. It is a tubuloalveolar gland in the stallion, bull, and ram. It is absent in the dog. The pale-staining secretory cells are columnar or pyramidal and have basally displaced nuclei. Secretory cells Duct Secretory cells </entry>
<entry linktype="AI" linkname="EUR-017-033" title="Figure 17.33: Penis, x.s., Puppy">Penis, x.s., Puppy. Section is through the developing os penis, which is present in carnivores. Smooth muscle Os penis Corpus spongiosum Urethra, lumen </entry>
<entry linktype="AI" linkname="EUR-017-034" title="Figure 17.34: Penis, x.s., Puppy">Penis, x.s., Puppy. Detail of the urethra and portion of the os penis. Lamina propria Urethra, lumen Transitional epithelium Cavernous space Spongy bone Cavernous space </entry>
<entry linktype="AI" linkname="EUR-017-035" title="Figure 17.35: Penis, l.s., Tomcat">Penis, l.s., Tomcat. In the tomcat, the distal portion of the corpus cavernosum consists largely of nonerectile, adipose tissue. A small os penis is present in the glans, and small spines are present on the surface of the glans of the tomcat. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Corpus spongiosum Corpus spongiosum Corpus cavernosum Urethra, lumen Epidermal spine Os penis </entry>
<entry linktype="AI" linkname="EUR-017-036" title="Figure 17.36: Glans Penis, l.s., Tomcat">Glans Penis, l.s., Tomcat. Detail of a keratinized epidermal spine. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Epidermal spine Dermis </entry>
<entry linktype="AI" linkname="EUR-017-037" title="Figure 17.37: Penile Urethra, x.s., Stallion">Penile Urethra, x.s., Stallion. Portion of the penile urethra with abundant cavernous spaces of the corpus spongiosum. Pyknotic nucleus Alveolus Septum Neuromuscular spindle Alveolus </entry>
<entry linktype="AI" linkname="EUR-017-038" title="Figure 17.38: Corpus Spongiosum, Body of Penis, Stallion">Corpus Spongiosum, Body of Penis, Stallion. The cavernous spaces of the stallion and carnivore are surrounded by connective tissue rich in elastic fibers and by many bundles of smooth muscle. Cavernous space Endothelium Connective tissue Smooth muscle Endothelium Cavernous space Smooth muscle Cavernous space </entry>
<entry linktype="AI" linkname="EUR-017-039" title="Figure 17.39: Penile Urethra, x.s., Stallion">Penile Urethra, x.s., Stallion. The epithelial lining of the urethra in this section is stratified columnar. The epithelium, however, is variable in the penile urethra and in places may also be simple columnar, transitional, or stratified cuboidal. Lamina propria Stratified columnar epithelium Lamina propria </entry>
<entry linktype="AI" linkname="EUR-017-040" title="Figure 17.40: Body of Penis, Stallion">Body of Penis, Stallion. Large masses of smooth muscle surround the cavernous spaces of the corpus cavernosum of the stallion. Smooth muscle Cavernous space Cavernous space Smooth muscle Connective tissue Cavernous space Connective tissue Cavernous space </entry>
<entry linktype="AI" linkname="EUR-017-041" title="Figure 17.41: Body of Penis, x.s., Boar">Body of Penis, x.s., Boar. A portion of the sigmoid flexure, including the retractor penis muscle. Retractor penis muscle Tunica albuginea Cavernous space Cavernous space Connective tissue trabecula Corpus cavernosum Connective tissue trabecula </entry>
<entry linktype="AI" linkname="EUR-017-042" title="Figure 17.42: Body of Penis, x.s., Boar (Orcein)">Body of Penis, x.s., Boar (Orcein). The connective tissue surrounding the cavernous spaces of the corpus cavernosum is rich in elastic fibers in the boar and ruminants. Elastic fibers Cavernous space Connective tissue trabecula Cavernous space Elastic fibers Connective tissue trabecula Elastic fibers Tunica albuginea </entry>
<entry linktype="AI" linkname="EUR-017-043" title="Figure 17.43: Body of Penis, Boar">Body of Penis, Boar. In the boar and ruminant, the cavernous spaces of the corpus cavernosum are invested largely by connective tissue and only a smattering of smooth muscle. Connective tissue trabecula Cavernous space Adipose tissue Cavernous space Smooth muscle Cavernous space Smooth muscle </entry>
<entry linktype="AI" linkname="EUR-017-044" title="Figure 17.44: Penile Urethra, x.s., Ram">Penile Urethra, x.s., Ram. The distribution of the cavernous spaces of the corpus spongiosum of the penile urethra is especially well represented in this section. Tunica albuginea Cavernous space Urethra, lumen Cavernous space Tunica albuginea </entry>
<entry linktype="AI" linkname="EUR-017-045" title="Figure 17.45: Body of Penis, x.s., Ram (Orcein)">Body of Penis, x.s., Ram (Orcein). The cavernous spaces of the corpus spongiosum are surrounded by connective tissue rich in elastic fibers in boars and ruminants. Tunica albuginea Cavernous space Cavernous space Elastic fibers Urethra, lumen Transitional epithelium </entry>
<entry linktype="AI" linkname="EUR-017-046" title="Figure 17.46: Helicine Artery, Body of Penis, Ram (Orcein)">Helicine Artery, Body of Penis, Ram (Orcein). The corpus cavernosum contains helicine arteries, which are tortuous vessels with an abundance of elastic fibers throughout their walls. Trabecula Helicine artery Trabecula Cavernous space Tunica albuginea Cavernous space </entry>
<entry linktype="AI" linkname="EUR-017-047" title="Figure 17.47: Helicine Artery, Body of Penis, Ram (Masson's)">Helicine Artery, Body of Penis, Ram (Masson's). Junction of a helicine artery with a cavernous space in the corpus cavernosum. Helicine artery Cavernous space Smooth muscle Cavernous space </entry>
<entry linktype="AI" linkname="EUR-017-048" title="Figure 17.48: Urethral Process, x.s., Ram">Urethral Process, x.s., Ram. The urethral process is a tortuous, wormlike extension of the urethra in the ram and billy goat. One of the two fibrocartilaginous cords that parallel the urethra is shown. Epidermis Fibrocartilaginous cord Cavernous space Lamina propria Urethra, lumen Cavernous space </entry>
<entry linktype="AI" linkname="EUR-017-049" title="Figure 17.49: Urethral Pouch, Stallion">Urethral Pouch, Stallion. The urethral pouch, found only in the stallion, is filled with smegma, which is composed of desquamated epithelial cells and the secretion of the preputial glands. Stratified squamous epithelium Smegma </entry>
<entry linktype="AI" linkname="EUR-017-057" title="Figure 17.57: Junction of Rete Testis and Efferent Ductule, Rooster">Junction of Rete Testis and Efferent Ductule, Rooster. The epithelial cells lining efferent ductules vary in shape and many possess cilia. The rete testis is lined by squamous epithelial cells. Cilia Efferent ductule Efferent ductule Rete testis Spermatozoa Cilia Efferent ductule Rete testis </entry>
<entry linktype="AI" linkname="EUR-017-058" title="Figure 17.58: Efferent Ductule, x.s., Rooster">Efferent Ductule, x.s., Rooster. Detail of an efferent ductule. The epithelial cells vary in shape, and many bear cilia. The epithelium is folded and is surrounded by loose connective tissue. Occasionally, smooth muscle may be present. Cilia Cilia Spermatozoa </entry>
<entry linktype="AI" linkname="EUR-017-059" title="Figure 17.59: Connecting Duct and Efferent Ductule, Rooster">Connecting Duct and Efferent Ductule, Rooster. Connecting ducts present a smooth inner surface and are lined by a pseudostratified columnar epithelium with occasional basal cells. The epithelial cells are generally without cilia. In contrast, the efferent ductule has a folded lining, and its epithelial cells are mostly ciliated. Efferent ductule Connecting duct Spermatozoa </entry>
<entry linktype="AI" linkname="EUR-017-060" title="Figure 17.60: Duct of the Epididymis, Rooster">Duct of the Epididymis, Rooster. The duct of the epididymis has a larger diameter than a connecting duct, but otherwise is comparable in structure with the latter. Spermatozoa Connecting duct Duct of the epididymis Connecting duct Efferent ductule Efferent ductule </entry>
<entry linktype="AI" linkname="EUR-017-061" title="Figure 17.61: Vas Deferens, Distal, Rooster">Vas Deferens, Distal, Rooster. The lining epithelium is similar to that of the epididymis. A layer of smooth muscle separates the epithelium from the surrounding connective tissue. Spermatozoa Pseudostratified epithelium Smooth muscle </entry>
<entry linktype="AI" linkname="EUR-018-001" title="Figure 18.1: Ovary, Queen">Ovary, Queen. Follicles of various ages and a corpus luteum can be seen in the cortex. A portion of the vascular medulla is present. Corpus luteum Medulla Cortex Growing follicles </entry>
<entry linktype="AI" linkname="EUR-018-002" title="Figure 18.2: Ovary, Queen">Ovary, Queen. Early follicles in the outer region of the cortex. Primary follicle Stroma Stroma Primordial follicles Tunica albuginea </entry>
<entry linktype="AI" linkname="EUR-018-005" title="Figure 18.5: Ovary, Bitch">Ovary, Bitch. Portion of the wall of a tertiary follicle, and part of an adjacent corpus luteum. Membrana granulosa Antrum Theca externa Theca interna Granulosa lutein cell Granulosa lutein cell </entry>
<entry linktype="AI" linkname="EUR-018-006" title="Figure 18.6: Corpus Luteum, Ovary, Sow">Corpus Luteum, Ovary, Sow. Peripheral region of a corpus luteum showing theca lutein cells (small) and granulose lutein cells (large). Theca lutein cell Theca lutein cell Theca lutein cell Granulosa lutein cell Granulosa lutein cell </entry>
<entry linktype="AI" linkname="EUR-018-007" title="Figure 18.7: Ovary, Bitch">Ovary, Bitch. Atretic follicles, each with a swollen zona pellucida. Hypertrophied theca cells Zona pellucid Hypertrophied theca cells Zona pellucid Hypertrophied theca cells Interstitial gland Interstitial gland </entry>
<entry linktype="AI" linkname="EUR-018-008" title="Figure 18.8: Corpus Albicans, Ovary, Cow (Masson's)">Corpus Albicans, Ovary, Cow (Masson's). The scar tissue of the corpus albicans is stained bright blue-green in this preparation. Germinal epithelium Young tertiary follicle Corpus albicans </entry>
<entry linktype="AI" linkname="EUR-018-009" title="Figure 18.9: Ovary, Bitch">Ovary, Bitch. Several interstitial glands are visible within the stroma between two corpora lutea. Corpus luteum Interstitial gland Interstitial gland Granulosa lutein cell Corpus luteum </entry>
<entry linktype="AI" linkname="EUR-018-010" title="Figure 18.10: Interstitial Glands, Ovary, Bitch">Interstitial Glands, Ovary, Bitch. Cords of epithelioid cells form the parenchyma of interstitial glands. These glands are well developed in queens and bitches. Interstitial gland Interstitial gland </entry>
<entry linktype="AI" linkname="EUR-018-011" title="Figure 18.11: Hilus Cells, Ovary, Cow">Hilus Cells, Ovary, Cow. Clusters of epithelioid cells, located in the vicinity of the hilus, are called hilus cells. They resemble the epithelioid cells of the interstitial glands (see Figure 18.10). Hilus cells Hilus cells </entry>
<entry linktype="AI" linkname="EUR-018-012" title="Figure 18.12: Rete Ovarii, Ovary, Cow">Rete Ovarii, Ovary, Cow. Cords of cells, or channels lined by cuboidal epithelial cells, located in the medulla of the ovary are called the rete ovarii. They are considered to be homologous to the rete testis. Rete ovarii Rete ovarii </entry>
<entry linktype="AI" linkname="EUR-018-013" title="Figure 18.13: Fimbria of Infundibulum, Oviduct, Mare">Fimbria of Infundibulum, Oviduct, Mare. The mucosa of the fimbria is highly folded. Folds Folds </entry>
<entry linktype="AI" linkname="EUR-018-014" title="Figure 18.14: Fimbria of Infundibulum, Oviduct, Mare">Fimbria of Infundibulum, Oviduct, Mare. Detail of the wall. Note the smooth muscle of the thin muscularis. Columnar epithelium, ciliated Lamina propria Submucosa Muscularis Muscularis Serosa </entry>
<entry linktype="AI" linkname="EUR-018-015" title="Figure 18.15: Fimbria of Infundibulum, Oviduct, Cow">Fimbria of Infundibulum, Oviduct, Cow. Portions of the fimbria may lack smooth muscle, as in this example. Columnar epithelium, ciliated Lamina propria Submucosa Serosa </entry>
<entry linktype="AI" linkname="EUR-018-016" title="Figure 18.16: Infundibulum, Oviduct, Cow (Masson's)">Infundibulum, Oviduct, Cow (Masson's). The epithelium consists of ciliated, columnar epithelial cells and nonciliated, secretory cells. Extruded nuclei, which appear to arise from epithelial cells, are common. Secretory bleb Extruded nucleus Secretory bleb Cilia Extruded nucleus Lamina propria </entry>
<entry linktype="AI" linkname="EUR-018-017" title="Figure 18.17: Infundibulum, Neck, Oviduct, x.s., Cow">Infundibulum, Neck, Oviduct, x.s., Cow. The mucosa is highly folded, and the muscularis is thin. Serosa Folds Muscularis </entry>
<entry linktype="AI" linkname="EUR-018-018" title="Figure 18.18: Ampulla, Oviduct, x.s., Cow">Ampulla, Oviduct, x.s., Cow. The mucosa is highly folded. The muscularis is relatively thick. Compare with Figure 18.17. Muscularis Folds Adipose tissue, mesosalpinx Serosa </entry>
<entry linktype="AI" linkname="EUR-018-019" title="Figure 18.19: Isthmus, Oviduct, x.s., Mare">Isthmus, Oviduct, x.s., Mare. The mucosa of the isthmus has fewer folds than any other part of the oviduct. The muscularis is thickest in this part of the oviduct. Circular muscle Longitudinal muscle Folds </entry>
<entry linktype="AI" linkname="EUR-018-020" title="Figure 18.20: Uterine Horn, x.s., Anestrus, Bitch">Uterine Horn, x.s., Anestrus, Bitch. The endometrium is thin and the glands are sparse in anestrus. Stratum vasculare Myometrium, circular Endometrial gland Myometrium, longitudinal </entry>
<entry linktype="AI" linkname="EUR-018-021" title="Figure 18.21: Uterine Horn, x.s., Anestrus, Queen">Uterine Horn, x.s., Anestrus, Queen. The lumen of the anestrus uterus is lined by a simple cuboidal epithelium. Cuboidal epithelium Endometrial gland Endometrial gland </entry>
<entry linktype="AI" linkname="EUR-018-022" title="Figure 18.22: Uterine Horn, x.s., Proestrus, Bitch">Uterine Horn, x.s., Proestrus, Bitch. In proestrus, the endometrium becomes thicker and the glands enlarge. Endometrial gland Endometrial gland Myometrium, circular Myometrium, longitudinal Stratum vasculare </entry>
<entry linktype="AI" linkname="EUR-018-023" title="Figure 18.23: Uterine Horn, x.s., Proestrus, Bitch">Uterine Horn, x.s., Proestrus, Bitch. Luminal epithelial cells become columnar during proestrus and estrus. Columnar epithelium Endometrial gland Endometrial gland </entry>
<entry linktype="AI" linkname="EUR-018-024" title="Figure 18.24: Uterine Horn, x.s., Estrus, Bitch">Uterine Horn, x.s., Estrus, Bitch. A thick endometrium and highly developed glands are characteristic of the estrous uterus. Endometrial gland Myometrium, circular Myometrium, longitudinal Endometrial gland Stratum vasculare </entry>
<entry linktype="AI" linkname="EUR-018-025" title="Figure 18.25: Uterine Horn, x.s., Diestrus, Bitch">Uterine Horn, x.s., Diestrus, Bitch. The endometrium and its glands become fully developed during diestrus. Endometrial gland Endometrial gland Myometrium, circular </entry>
<entry linktype="AI" linkname="EUR-018-026" title="Figure 18.26: Mesometrium, Bitch">Mesometrium, Bitch. The mesometrium contains an abundance of smooth muscle and numerous blood vessels. Smooth muscle of the mesometrium is continuous with the outer, longitudinal layer of the myometrium. Myometrium, circular Endometrial gland Myometrium, longitudinal Mesometrium </entry>
<entry linktype="AI" linkname="EUR-018-027" title="Figure 18.27: Uterine Horn, Brood Mare (Orcein)">Uterine Horn, Brood Mare (Orcein). There is an abundance of elastic fibers (red-brown in this micrograph) in the intima and adventitia of blood vessels of the uterus of animals that have been through a pregnancy. The section is from the midregion of the myometrium. Myometrium Artery Vein Artery Myometrium Vein </entry>
<entry linktype="AI" linkname="EUR-018-028" title="Figure 18.28: Uterine Horn, Brood Mare">Uterine Horn, Brood Mare. Detail of a portion of an artery in the myometrium. The intima becomes thickened with elastic fibers and smooth muscle in animals that have experienced a pregnancy. The adventitia also becomes heavily infiltrated with elastic fibers. Tunica intima Tunica media Tunica adventitia </entry>
<entry linktype="AI" linkname="EUR-018-029" title="Figure 18.29: Uterine Horn, x.s., Metestrus, Cow">Uterine Horn, x.s., Metestrus, Cow. Metestrous bleeding occurs in the cow. Numerous erythrocytes of hemorrhagic regions can be seen beneath the surface epithelium (see Figure 18.30). Hemorrhagic region Hemorrhagic region Endometrial gland Myometrium, circular Myometrium, longitudinal </entry>
<entry linktype="AI" linkname="EUR-018-030" title="Figure 18.30: Uterus, Metestrus, Cow">Uterus, Metestrus, Cow. Detail of Figure 18.29. Hemorrhagic regions are evident in the endometrium beneath the surface epithelium. The epithelial cells are cuboidal during met estrus in the cow. Endometrial gland Hemorrhagic region Endometrial gland Cuboidal epithelium Hemorrhagic region Hemorrhagic region </entry>
<entry linktype="AI" linkname="EUR-018-031" title="Figure 18.31: Uterine Horn, Cow (Masson's)">Uterine Horn, Cow (Masson's). The epithelial cells lining the uterine glands are sometimes ciliated, as in this section. Cilia </entry>
<entry linktype="AI" linkname="EUR-018-032" title="Figure 18.32: Caruncle, Uterus, x.s., Cow">Caruncle, Uterus, x.s., Cow. The endometrium of the uterus of ruminants contains nonglandular, highly cellular prominences called caruncles. Uterine glands that lie deep to the caruncle open near its base. Caruncle Endometrial gland Endometrial gland Myometrium, circular </entry>
<entry linktype="AI" linkname="EUR-018-033" title="Figure 18.33: Caruncle, Uterus, Cow">Caruncle, Uterus, Cow. The caruncle consists of highly cellular (mostly fibroblasts) connective tissue and numerous blood vessels located beneath the epithelium. Blood vessels Blood vessels </entry>
<entry linktype="AI" linkname="EUR-018-034" title="Figure 18.34: Placenta (Zonary and Endotheliochorial), Bitch (Drawing)">Placenta (Zonary and Endotheliochorial), Bitch (Drawing). Carnivores have a zonary placenta that appears, grossly, as a beltlike band around the middle of the chorionic sac. The chorionic (fetal) tissue penetrates to the endothelium of the maternal blood vessels. A placenta with this type of fetal-maternal junction is called an endotheliochorial placenta. The association between the maternal endothelium and syntrophoblast can be seen in Figures 18.37 and 18.39. Note: This drawing is of a section through a portion of one of the edges of the zonary placenta of a bitch. Marginal hematoma Chorion laeve Fig. 18.42 Fig. 18.41 Fig. 18.39 Fig. 18.35 Fig. 18.36 Chorioallantoic membrane Allantoic blood vessel Placental labyrinth Spongy layer Supraglandular layer Deep glandular layer Myometrium </entry>
<entry linktype="AI" linkname="EUR-018-035" title="Figure 18.35: Placenta (Zonary and Endotheliochorial), Bitch (Trichrome)">Placenta (Zonary and Endotheliochorial), Bitch (Trichrome). Section through the deepest layers of the placenta. See Figure 18.34 for location. The spongy layer is formed by the occluded uterine glands in the mid-region of the endometrium. The deep glandular layer consists of the bases of the uterine glands. The supraglandular layer is a sheet of connective tissue between the deep glandular and spongy layers. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Spongy layer Spongy layer Supraglandular layer Deep glandular layer Myometrium </entry>
<entry linktype="AI" linkname="EUR-018-036" title="Figure 18.36: Placenta (Zonary and Endotheliochorial), Bitch (Trichrome)">Placenta (Zonary and Endotheliochorial), Bitch (Trichrome). Portion of the chorioallantoic membrane and the placental labyrinth. See Figure. 18.34 for location. The chorioallantoic membrane in this micrograph appears thicker than normal because of the presence of extensive space artifact. Note the presence of fetal blood vessels in the chorioallantoic membrane. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Allantoic epithelium Allantoic blood vessel Allantoic blood vessel Placental labyrinth </entry>
<entry linktype="AI" linkname="EUR-018-037" title="Figure 18.37: Placenta (Zonary and Endotheliochorial), Bitch (Trichrome)">Placenta (Zonary and Endotheliochorial), Bitch (Trichrome). Section is through the placental labyrinth. Both maternal and fetal components of this endotheliochorial placenta can be seen. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Cytotrophoblast Chorioallantoic connective tissue Syntrophoblast Allantoic blood vessel Maternal blood vessel Syntrophoblast Cytotrophoblast </entry>
<entry linktype="AI" linkname="EUR-018-038" title="Figure 18.38: Placenta (Zonary and Endotheliochorial), Bitch (Trichrome)">Placenta (Zonary and Endotheliochorial), Bitch (Trichrome). Detail of the placental labyrinth. The maternal blood vessels are lined by endothelial cells with bulging nuclei. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Syntrophoblast Maternal blood vessel Allantoic blood vessel Cytotrophoblast Maternal blood vessel Cytotrophoblast </entry>
<entry linktype="AI" linkname="EUR-018-039" title="Figure 18.39: Placenta (Zonary and Endotheliochorial), Bitch (Trichrome)">Placenta (Zonary and Endotheliochorial), Bitch (Trichrome). Trophoblastic projections, lined by large, pale, vacuolated cells, protrude into spaces (areolae) in the region where the placental labyrinth is forming. A portion of the maternal tissue, which has been partially destroyed by the invading trophoblast, is represented by the red-stained, necrotic tissue seen in the lower left quadrant of the micrograph. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Trophoblastic projection, vacuolated cells Necrotic endometrial tissue Trophoblastic projection, vacuolated cells Necrotic endometrial tissue </entry>
<entry linktype="AI" linkname="EUR-018-040" title="Figure 18.40: Placenta (Zonary and Endotheliochorial), Bitch (Trichrome)">Placenta (Zonary and Endotheliochorial), Bitch (Trichrome). Detail of Figure 18.39. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Necrotic endometrial tissue Eroded endometrial epithelium Trophoblastic projection, vacuolated cells Eroded endometrial epithelium Eroded endometrial epithelium Maternal blood vessel Necrotic endometrial tissue Eroded endometrial epithelium </entry>
<entry linktype="AI" linkname="EUR-018-041" title="Figure 18.41: Placenta (Zonary and Endotheliochorial), Bitch (Trichrome)">Placenta (Zonary and Endotheliochorial), Bitch (Trichrome). A portion of a marginal hematoma, consisting of large compartments filled with blood derived from hemorrhaging uterine blood vessels, is shown. See Figure 18.34 for location. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Marginal hematoma Marginal hematoma Placental labyrinth Spongy zone </entry>
<entry linktype="AI" linkname="EUR-018-042" title="Figure 18.42: Chorion Laeve, Bitch (Trichrome)">Chorion Laeve, Bitch (Trichrome). The chorion laeve is the part of the chorioallantoic sac that is not involved in the formation of the placenta. Its surface is smooth and is apposed to the uterine epithelium. This section is from the region adjacent to the hematoma of the placenta. See Figure 18.34 for location. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Uterine gland Uterine gland Chorion laeve, epithelium Uterus, epithelium </entry>
<entry linktype="AI" linkname="EUR-018-043" title="Figure 18.43: Placenta (Diffuse and Epitheliochorial), Mare">Placenta (Diffuse and Epitheliochorial), Mare. In the horse, small tufts of branched chorioallantoic villi interdigitate with crypts of the endometrium. Together, the tufts and the crypts form structures called microplacentomes. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Chorioallantoic membrane Allantoic blood vessel Chorioallantoic villus Crypt Microplacentome Chorioallantoic villus Microplacentome Uterine gland </entry>
<entry linktype="AI" linkname="EUR-018-044" title="Figure 18.44: Placenta (Diffuse and Epitheliochorial), Mare">Placenta (Diffuse and Epitheliochorial), Mare. Detail of a microplacentome. Longitudinal and cross sections of chorioallantoic villi are surrounded by endometrial crypts. The epithelium of the crypts, which may vary in height, is flattened in this region. The villi contain blood vessels and connective tissue and are covered by pink-stained trophoblast cells. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Allantoic blood vessel Crypt, epithelium Maternal blood vessel Chorioallantoic villus, epithelium Allantoic blood vessel Crypt, epithelium Chorioallantoic villus, epithelium </entry>
<entry linktype="AI" linkname="EUR-018-045" title="Figure 18.45: Placenta (Diffuse and Epitheliochorial), Mare">Placenta (Diffuse and Epitheliochorial), Mare. Detail of a placentome adjacent to the endometrium. The epithelium of the endometrial crypt consists of pale, cuboidal cells. The epithelium of the chorioallantoic villi is formed from pink-stained cuboidal and low columnar cells. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Allantoic blood vessel Endometrium, connective tissue Crypt, epithelium Maternal blood vessel Crypt, epithelium Chorioallantoic villus, epithelium Allantoic blood vessel Uterine gland Chorioallantoic villus, epithelium Maternal blood vessel </entry>
<entry linktype="AI" linkname="EUR-018-046" title="Figure 18.46: Placenta (Diffuse and Epitheliochorial), Sow (Trichrome)">Placenta (Diffuse and Epitheliochorial), Sow (Trichrome). The placenta of the sow is folded, diffuse, and epitheliochorial. Folds of the chorioallantoic membrane interdigitate with folds of the uterus. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Chorioallantoic membrane, primary fold Endometrium, secondary fold Uterine gland Endometrium, primary fold Myometrium Chorioallantoic membrane, secondary fold Chorioallantoic membrane, secondary fold Chorioallantoic membrane, primary fold Endometrium, secondary fold </entry>
<entry linktype="AI" linkname="EUR-018-047" title="Figure 18.47: Placenta (Diffuse and Epitheliochorial), Sow (Trichrome)">Placenta (Diffuse and Epitheliochorial), Sow (Trichrome). Interdigitating secondary folds of the chorioallantoic membrane and endometrium. The bases of the folds of the chorioallantoic membrane are lined by high columnar epithelial cells, whereas the crests of the maternal folds are covered by shorter columnar cells. The remainder of both epithelial surfaces is lined by cuboidal or flattened cells. Note that the chorioallantoic epithelial surface is invaded by capillaries. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Allantoic blood vessel High columnar cells Low columnar cells Allantoic blood vessel Chorioallantoic membrane, primary fold Allantoic blood vessel Space artifact Chorioallantoic membrane, secondary fold Endometrium, secondary fold Cuboidal cells </entry>
<entry linktype="AI" linkname="EUR-018-048" title="Figure 18.48: Placenta (Cotyledonary and Epitheliochorial), Cow">Placenta (Cotyledonary and Epitheliochorial), Cow. A section through a placentome formed from the association of a cotyledon (clumps of chorioallantoic villi) with a uterine caruncle (endometrial elevation). Note that the endometrial epithelium of the intercotyledonary region is discontinuous. Allantoic blood vessel Chorioallantoic membrane Placentome Stalk of placentome Intercotyledonary endometrium </entry>
<entry linktype="AI" linkname="EUR-018-050" title="Figure 18.50: Placenta (Cotyledonary and Epitheliochorial), Cow">Placenta (Cotyledonary and Epitheliochorial), Cow. Detail of a portion of a placentome adjacent to the stalk. Note that the cryptal epithelium is cuboidal or flattened. The epithelium of the chorioallantoic villus consists of irregularly shaped cells and binucleate giant cells (diplokaryocytes). Cryptal epithelium Chorioallantoic villus, branch Diplokaryocyte Diplokaryocyte Crypt Cryptal epithelium </entry>
<entry linktype="AI" linkname="EUR-018-051" title="Figure 18.51: Cervix of Uterus, Bitch">Cervix of Uterus, Bitch. The mucosa of the cervix is thrown into folds. The epithelium of the bitch's cervix is stratified squamous. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Stratified squamous epithelium Stratified squamous epithelium Lamina propria </entry>
<entry linktype="AI" linkname="EUR-018-052" title="Figure 18.52: Cervix of Uterus, Mare">Cervix of Uterus, Mare. Cervical folds are evident. Tertiary fold Secondary fold Secondary fold Primary fold Primary fold </entry>
<entry linktype="AI" linkname="EUR-018-053" title="Figure 18.53: Cervix of Uterus, Mare (Masson's)">Cervix of Uterus, Mare (Masson's). The cervical epithelium is simple columnar, except in the bitch (see Figure 18.51). Epithelial cells may be ciliated. Cilia Cilia Lamina propria </entry>
<entry linktype="AI" linkname="EUR-018-054" title="Figure 18.54: Vagina, Anestrus, Bitch">Vagina, Anestrus, Bitch. The epithelium of the carnivore's anestrous vagina is stratified squamous to stratified cuboidal. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Stratified epithelium Lamina propria </entry>
<entry linktype="AI" linkname="EUR-018-055" title="Figure 18.55: Vagina, Estrus, Queen">Vagina, Estrus, Queen. In carnivores, the vagina is lined by a thickened, keratinized, stratified squamous epithelium during estrus. Exfoliated keratinized cells are visible in the vaginal lumen in this micrograph. Stratified squamous epithelium Keratinized cells Lamina propria </entry>
<entry linktype="AI" linkname="EUR-018-056" title="Figure 18.56: Urethra, x.s., Queen">Urethra, x.s., Queen. Section was taken from the region close to the bladder. This portion of the urethra is lined by a transitional epithelium. (Photomicrograph of a histologic section borrowed from the College of Veterinary Medicine, Iowa State University.) Transitional epithelium Lamina propria Muscularis Muscularis Adventitia </entry>
<entry linktype="AI" linkname="EUR-018-057" title="Figure 18.57: Junction of Vestibule and Urethra, x.s., Queen">Junction of Vestibule and Urethra, x.s., Queen. Near the vestibule, the urethra is lined by a stratified squamous epithelium. Note the presence of cavernous spaces in the connective tissue adjacent to the muscularis. Such spaces occur only in the distal two-thirds of the urethra in the doe, ewe, and queen. In all other domestic mammals, cavernous spaces occur throughout the entire length of the urethra. Vestibular epithelium Muscularis Urethral epithelium Cavernous spaces Minor vestibular gland </entry>
<entry linktype="AI" linkname="EUR-018-058" title="Figure 18.58: Vestibule, Queen">Vestibule, Queen. Detail of a minor vestibular gland. The secretory tubules of these branched, tubular glands are lined by columnar cells. Their ducts are lined by stratified squamous epithelium. Vestibular epithelium Duct Columnar cells </entry>
<entry linktype="AI" linkname="EUR-018-059" title="Figure 18.59: Vestibule, Queen">Vestibule, Queen. Detail of a major vestibular gland. These glands are found in queens and ruminants. They are compound tubular glands with secretory units like those of the minor vestibular glands (see Figure 18.58). Columnar cells Columnar cells Duct </entry>
<entry linktype="AI" linkname="EUR-018-060" title="Figure 18.60: Vaginal Smear, Anestrus, Bitch (Hema-3)">Vaginal Smear, Anestrus, Bitch (Hema-3). During anestrus, parabasal and intermediate cells are the predominant epithelial cells present. See the introduction for a description of cell types. Neutrophils and bacteria may be present in limited numbers. Parabasal cell Parabasal cell </entry>
<entry linktype="AI" linkname="EUR-018-061" title="Figure 18.61: Vaginal Smear, Early Proestrus, Bitch (Hema-3)">Vaginal Smear, Early Proestrus, Bitch (Hema-3). During early to mid proestrus, smears may contain neutrophils, erythrocytes, and various epithelial cell types (parabasal, intermediate, superficial intermediate, and superficial cells). Parabasal cell Intermediate cell Erythrocyte Superficial intermediate cell Parabasal cell Superficial intermediate cell Intermediate cell Superficial intermediate cell Erythrocyte Superficial cell </entry>
<entry linktype="AI" linkname="EUR-018-062" title="Figure 18.62: Vaginal Smear, Mid to Late Proestrus, Bitch (Diff-Quik)">Vaginal Smear, Mid to Late Proestrus, Bitch (Diff-Quik). In late proestrus, superficial intermediate and superficial cells are predominant. Neutrophils decrease in number at this time. Erythrocyte Parabasal cell Erythrocyte Superficial cell Superficial intermediate cell Neutrophil Superficial cell Superficial cell Superficial cell Superficial intermediate cell Neutrophil </entry>
<entry linktype="AI" linkname="EUR-018-063" title="Figure 18.63: Vaginal Smear, Estrus, Bitch (Diff-Quik)">Vaginal Smear, Estrus, Bitch (Diff-Quik). Most (90% or more) of the epithelial cells from a bitch in estrus are superficial cells. Erythrocytes may be present in small numbers. Some estrous smears may contain large numbers of bacteria. Neutrophils are not normally present. Superficial cell Superficial cell Superficial cell Superficial cell Erythrocyte </entry>
<entry linktype="AI" linkname="EUR-018-064" title="Figure 18.64: Vaginal Smear, Diestrus, Bitch (Diff-Quik)">Vaginal Smear, Diestrus, Bitch (Diff-Quik). There is a significant change in the numbers of epithelial-cell types during diestrus. Superficial cells decrease, and parabasal and intermediate cells increase. Neutrophils usually reappear during diestrus. Because erythrocytes may be present in smears from bitches in early diestrus, it is not possible to distinguish proestrus from diestrus on the basis of a single smear. Intermediate cell Superficial cell Parabasal cell Neutrophil Superficial cell Intermediate cell Parabasal cell Superficial intermediate cell Superficial cell Parabasal cell Neutrophil Superficial intermediate cell </entry>
<entry linktype="AI" linkname="EUR-018-065" title="Figure 18.65: Ovary, Hen">Ovary, Hen. A portion of the ovarian cortex with developing follicles. Follicle, early Follicle, late Follicle, early Oocyte Follicle, early </entry>
<entry linktype="AI" linkname="EUR-018-066" title="Figure 18.66: Ovary, Vacuolar Cells, Hen">Ovary, Vacuolar Cells, Hen. A portion of the cortex with a mass of fat-laden vacuolar cells. The latter may represent regressing postovulatory follicles. Vacuolar cells Follicle, early Follicle, early Medulla </entry>
<entry linktype="AI" linkname="EUR-018-067" title="Figure 18.67: Ovary, Vacuolar Cells, Hen">Ovary, Vacuolar Cells, Hen. Detail of Figure 18.66. Vacuolar cells have pyknotic nuclei and contain numerous fat vacuoles. Cell boundaries are often indistinct. Vacuolar cells Vacuolar cells </entry>
<entry linktype="AI" linkname="EUR-018-068" title="Figure 18.68: Ovary, Granulocytes, Hen">Ovary, Granulocytes, Hen. Granulocytes are often found in the cortex of mature ovaries. The acidophilic granules of these cells impart a red tinge to a large area of the cortex in this micrograph. Medulla Oocyte, nucleus Oocyte, yolk-laden cytoplasm Granulocytes </entry>
<entry linktype="AI" linkname="EUR-018-069" title="Figure 18.69: Ovary, Developing Follicle, Hen">Ovary, Developing Follicle, Hen. A portion of the wall of a developing follicle. Note the flattened cells of the theca interna and the presence of interstitial cells in the theca externa. Oocyte, yolk-laden cytoplasm Theca interna Membrana granulosa Interstitial cells Perivitelline membrane Theca externa Theca externa </entry>
<entry linktype="AI" linkname="EUR-018-070" title="Figure 18.70: Ovary, Atretic Follicle, Hen">Ovary, Atretic Follicle, Hen. In some atretic follicles, interstitial (luteal) cells proliferate, hypertrophy, and migrate inward (see Figure. 18.71). Atretic follicle Interstitial cells Interstitial cells </entry>
<entry linktype="AI" linkname="EUR-018-072" title="Figure 18.72: Ovary, Atretic Follicle, Hen">Ovary, Atretic Follicle, Hen. Cells of the membrane granulosa have proliferated, forming a thick layer characteristic of many atretic follicles. Membrana granulosa, thickened Developing follicle Developing follicle </entry>
<entry linktype="AI" linkname="EUR-018-073" title="Figure 18.73: Oviduct, Diagrammatic Drawing, Hen">Oviduct, Diagrammatic Drawing, Hen. The oviduct of the hen is divisible into an infundibulum, magnum, isthmus, uterus, and vagina. Infundibulum Magnum Isthmus Uterus (shell gland) Vagina Ovary Cloaca </entry>
<entry linktype="AI" linkname="EUR-018-074" title="Figure 18.74: Funnel of Infundibulum, Oviduct, x.s., Hen">Funnel of Infundibulum, Oviduct, x.s., Hen. The mucosa is thrown into shallow ridges that increase in height as the funnel narrows toward the neck region. The epithelium is ciliated, simple columnar. Scattered bundles of smooth muscle form the muscularis. A serosa covers the funnel externally. Mucosa Muscularis Serosa </entry>
<entry linktype="AI" linkname="EUR-018-076" title="Figure 18.76: Neck of Infundibulum, x.s., Oviduct, Hen">Neck of Infundibulum, x.s., Oviduct, Hen. Detail of mucosa showing folds lined by ciliated columnar cells. The bottoms of the grooves between the folds are lined by nonciliated secretory cells. Glandular groove Glandular groove Ciliated epithelium </entry>
<entry linktype="AI" linkname="EUR-018-077" title="Figure 18.77: Neck of Infundibulum and Magnum, x.s., Oviduct, Hen">Neck of Infundibulum and Magnum, x.s., Oviduct, Hen. The primary mucosal folds of the magnum are taller and broader vis--vis the infundibulum, because of the presence of numerous tubular glands. Mucosal fold, magnum Mucosal fold, infundibulum </entry>
<entry linktype="AI" linkname="EUR-018-078" title="Figure 18.78: Magnum, x.s., Oviduct, Hen">Magnum, x.s., Oviduct, Hen. Portion of a fold. Depending on their activity, the tubular glands of the magnum exhibit distinctive features. Three morphologic phases of activity can be recognized (regenerating, secretory, resting). See Figures 18.80 and 18.81 for details. Lamina propria Secretory gland Pseudostratified columnar epithelium Regenerating gland Resting gland Pseudostratified columnar epithelium Resting gland </entry>
<entry linktype="AI" linkname="EUR-018-079" title="Figure 18.79: Magnum, Oviduct, Hen">Magnum, Oviduct, Hen. Detail of the epithelium. Ciliated columnar and secretory (goblet) cells comprise the epithelium of the magnum. The nuclei of the secretory cells are round and are located close to the base of the cell, whereas the nuclei of the ciliated cells are oval and occupy the central to apical region of the cell. Accordingly, the epithelium is pseudostratified columnar. Ciliated cell Ciliated cell Secretory cell Secretory cell </entry>
<entry linktype="AI" linkname="EUR-018-080" title="Figure 18.80: Magnum, Oviduct, Hen">Magnum, Oviduct, Hen. Detail of regenerating tubular glands. These glands have clearly defined lumens. The secretory cells are cuboidal. Epithelium, regenerating gland </entry>
<entry linktype="AI" linkname="EUR-018-081" title="Figure 18.81: Magnum, Oviduct, Hen">Magnum, Oviduct, Hen. Detail of secretory tubular glands and resting tubular glands. The cells of the secretory stage are characterized by pyknotic, basal nuclei. The entire cytoplasm is filled with strongly acidophilic granules. The glandular lumens may be dilated by secreted albumen. The cytoplasm of the cells in the resting stage has a frothy appearance, and the lumens of the glands are obscure. Albumen Albumen Epithelium, secretory gland Epithelium, secretory gland Albumen Epithelium, resting gland </entry>
<entry linktype="AI" linkname="EUR-018-082" title="Figure 18.82: Isthmus, x.s., Oviduct, Hen">Isthmus, x.s., Oviduct, Hen. The primary folds of the isthmus are not as broad as those of the magnum. Compare with Figure 18.77. They are somewhat angular in appearance. A portion of an adjacent region of the magnum is present in this micrograph. Isthmus, primary fold Isthmus, primary fold Magnum Muscularis </entry>
<entry linktype="AI" linkname="EUR-018-083" title="Figure 18.83: Isthmus, Oviduct, Hen">Isthmus, Oviduct, Hen. A portion of the epithelium and underlying tubular glands. The epithelium is ciliated pseudostratified columnar. A tubular gland can be seen opening to the surface. The glandular cells do not undergo obvious cyclic changes as in the magnum. Pseudostratified epithelium Tubular gland Tubular gland </entry>
<entry linktype="AI" linkname="EUR-018-084" title="Figure 18.84: Uterus (Shell Gland), Oviduct, Hen">Uterus (Shell Gland), Oviduct, Hen. The folds of the uterus are not as broad as those of the magnum, and there is less glandular tissue. This section was taken from a uterus that had been fixed while containing an egg. Accordingly, the luminal surface is somewhat concave. Concave surface Primary fold Secondary fold Secondary fold </entry>
<entry linktype="AI" linkname="EUR-018-085" title="Figure 18.85: Uterus (Shell Gland), Oviduct, Hen">Uterus (Shell Gland), Oviduct, Hen. Ducts of complex, branched, tubular glands pierce the ciliated pseudostratified columnar epithelium at intervals. Ducts are formed from polygonal gland cells. Glandular epithelium Glandular epithelium Duct Pseudostratified epithelium Blood vessel Glandular epithelium </entry>
<entry linktype="AI" linkname="EUR-018-086" title="Figure 18.86: Uterus (Shell Gland), Oviduct, Hen">Uterus (Shell Gland), Oviduct, Hen. Basal cells (nuclei close to the basement membrane) of the pseudostratified epithelium may contain vacuoles above and below their nuclei. Apical cells (nuclei centrally located) contain numerous granules before releasing their secretion. Apical cell Vacuole Basal cell, nucleus Vacuole Erythrocyte in capillary Glandular epithelium </entry>
<entry linktype="AI" linkname="EUR-018-087" title="Figure 18.87: Vagina, x.s., Oviduct, Hen">Vagina, x.s., Oviduct, Hen. The mucosa of the vagina is characterized by long, slender, primary folds bearing numerous small secondary folds. The muscularis is highly developed. Primary fold Secondary fold Primary fold Secondary fold Muscularis </entry>
<entry linktype="AI" linkname="EUR-018-088" title="Figure 18.88: Vagina, Proximal, Oviduct, Hen">Vagina, Proximal, Oviduct, Hen. Sperm-host glands are tubular glands, lined by tall columnar cells, and are located within the mucosa of the vagina near the uterovaginal junction. Sperm are stored in these glands, remaining functional for up to 21 days. Pseudostratified epithelium Sperm-host gland Sperm-host gland </entry>
<entry linktype="AI" linkname="EUR-019-001" title="Figure 19.1: Eye, Sagittal Section, Dog">Eye, Sagittal Section, Dog. The relationship between various morphologic components of the canine eye are depicted. Bulbar conjunctiva Palpebral conjunctiva Filtration angle Ciliary muscle Sclera Choroid Tepetum lucidum Retina Optic nerve Scleral vencus plexus Bulbar cunjunctiva Palpebral cunjunctiva Dilator, myoepithelial cells Sphincter muscle Cornea Anterior chamber Posterior chamber Iris Limbus Ora ciliaris retinae Pars ciliaris retinae Pars iridica retinae, pigmented layer Cavity of vitreous humor Optic disc Lens Zonular fiber Ciliary process Pupil </entry>
<entry linktype="AI" linkname="EUR-019-002" title="Figure 19.2: Eye, Dog">Eye, Dog. Anterior, peripheral portion of the eye. Bulbar conjunctiva Sclera Scleral venous plexus Ciliary body Limbus Filtration angle Ciliary process Cornea Anterior chamber Iris Posterior chamber Lens </entry>
<entry linktype="AI" linkname="EUR-019-003" title="Figure 19.3: Lens, Equator, Horse">Lens, Equator, Horse. Newly formed and older lens fibers are visible in this section through the germinal zone. The latter is the marginal band of lens epithelium that lies around the equator. Its cells are capable of dividing throughout adult life. Lens capsule Lens epithelium Germinal zone Lens fibers, new Lens fibers, old </entry>
<entry linktype="AI" linkname="EUR-019-004" title="Figure 19.4: Ciliary Body, Dog">Ciliary Body, Dog. The epithelium of the ciliary body is called the pars ciliaris retinae. This portion of the nonphotosensitive retina consists of an inner (closer to the cavity of the vitreous humor), nonpigmented layer and an outer, heavily pigmented layer of cells. Sclera Ciliary muscle Vascular layer, choroid Pars ciliaris retinae </entry>
<entry linktype="AI" linkname="EUR-019-005" title="Figure 19.5: Ciliary Body, Cat (Orcein)">Ciliary Body, Cat (Orcein). In addition to smooth muscle (see Figure 19.4), the ciliary body contains an abundance of elastic fibers. Elastic fiber Elastic fiber Elastic fiber </entry>
<entry linktype="AI" linkname="EUR-019-006" title="Figure 19.6: Eye, Horse">Eye, Horse. In a section through a horse's eye, the limbus does not overlap the pectinate ligament. Compare with Figure 19.7. The filtration angle is indicated by the triangular-shaped area marked by the dashed line. Cornea Limbus Palpebral conjunctiva Bulbar conjunctiva Sclera Filtration angle Spaces of Fontana Corneoscleral trabecular meshwork Spaces of Fontana Pectinate ligament Iris Ciliary process </entry>
<entry linktype="AI" linkname="EUR-019-007" title="Figure 19.7: Eye, Pig">Eye, Pig. In a section through the eye of a domestic mammal other than the horse, the limbus overlaps the pectinate ligament. The area of the filtration angle is outlined by dots. Cornea Palpebral conjunctiva Bulbar conjunctiva Limbus Pectinate ligament Iris Sclera Spaces of Fontana Corneoscleral trabecular meshwork Uveal trabecular meshwork Filtration angle Ciliary process </entry>
<entry linktype="AI" linkname="EUR-019-008" title="Figure 19.8: Filtration Angle, Pig">Filtration Angle, Pig. Collagenous fibers, elastic fibers, fibroblasts, and pigment cells form the pectinate ligament and the uveal trabecular meshwork. The corneoscleral trabecular meshwork is a three-dimensional latticework of fine fibers of connective tissue and fibroblasts lying adjacent to the sclera. Pectinate ligament Descemet's membrane Corneoscleral trabecular meshwork Sclera Spaces of Fontana Uveal trabecular meshwork Spaces of Fontana </entry>
<entry linktype="AI" linkname="EUR-019-009" title="Figure 19.9: Ciliary Processes, Pig">Ciliary Processes, Pig. The nonpigmented cells of the epithelium of the ciliary processes cover the pigmented cells. Together these two layers of cells comprise the pars ciliaris retinae, which extends from the ora ciliaris retinae to the iris. The nonpigmented cells give rise to the zonular fibers. Iris Pigmented cells Nonpigmented cells Zonular fibers </entry>
<entry linktype="AI" linkname="EUR-019-010" title="Figure 19.10: Iris, Horse">Iris, Horse. The back surface of the iris is covered by a continuation of the pars ciliaris retinae and is called the pars iridica retinae. The surface layer of the pars iridica retinae consists of heavily pigmented cells, and its inner layer is formed by the contractile, pigmented myoepithelial cells that dilate the iris. Anteriorly, the iris is covered by a discontinuous layer of stromal cells. Sphincter muscle Sphincter muscle Stroma Myoepithelial cells Melanocyte Stroma Pigmented surface cells Sphincter muscle Stroma </entry>
<entry linktype="AI" linkname="EUR-019-011" title="Figure 19.11: Iris, Dog">Iris, Dog. The heavily pigmented cells of the pars iridica retinae cover the posterior surface of the iris. The myoepithelial cells of the pars iridica retinae are partially pigmented in the region of their nuclei. Myoepithelial cell, nucleus Pigmented surface cells Myoepithelial cell, cytoplasm Myoepithelial cell, nucleus Melanocyte Sphincter muscle </entry>
<entry linktype="AI" linkname="EUR-019-012" title="Figure 19.12: Iris, Cat">Iris, Cat. In the cat, the melanocytes of the iris are binucleate and contain rod-shaped melanosomes. Melanocyte Melanocyte Melanocyte </entry>
<entry linktype="AI" linkname="EUR-019-013" title="Figure 19.13: Corpus Nigrum, Goat">Corpus Nigrum, Goat. In ungulates, the pupillary border of the iris is differentiated into corpora nigra, which are vascularized outgrowths of the stroma and pigmented epithelium of the iris. Iris Cornea Corpus nigrum </entry>
<entry linktype="AI" linkname="EUR-019-014" title="Figure 19.14: Cornea, Dog">Cornea, Dog. The anterior surface is covered by a nonkeratinized stratified squamous epithelium. The posterior surface is covered by squamous or low cuboidal cells. Anterior epithelium Stroma Posterior epithelium Descemet's membrane Space artifacts </entry>
<entry linktype="AI" linkname="EUR-019-015" title="Figure 19.15: Junction of Cornea and Bulbar Conjunctiva, Pig">Junction of Cornea and Bulbar Conjunctiva, Pig. Both the cornea and bulbar conjunctiva are covered by a nonkeratinized stratified squamous epithelium at their junction. The basal border of the conjunctiva is irregular, and the cells of its deepest layers are smaller than those of the anterior epithelium of the cornea. Anterior epithelium Corneal stroma Bulbar conjunctiva, epithelium Bulbar conjunctiva, lamina propria Sclera </entry>
<entry linktype="AI" linkname="EUR-019-016" title="Figure 19.16: Ora Ciliaris Retinae, Dog">Ora Ciliaris Retinae, Dog. The transition zone between the photosensitive and the nonphotosensitive (pars ciliaris retinae) regions of the retina is named the ora ciliaris retinae. Pars ciliaris retinae Ora ciliaris retinae Sclera Choroid Retina, photosensitive </entry>
<entry linktype="AI" linkname="EUR-019-017" title="Figure 19.17: Optic Nerve, Sagittal Section, Dog">Optic Nerve, Sagittal Section, Dog. Nerve fibers of the retina converge to form the optic nerve at the optic disc (blind spot). Retina Optic disc Lamina cribrosa Choroid Sclera Optic nerve </entry>
<entry linktype="AI" linkname="EUR-019-018" title="Figure 19.18: Lamina Cribrosa, x.s., Dog">Lamina Cribrosa, x.s., Dog. At the lamina cribrosa the connective tissue of the sclera forms a sievelike framework, which subdivides the optic nerve into bundles of fibers. Sclera Nerve fibers, bundle of Nerve fibers, bundle of Lamina cribrosa Nerve fibers, bundle of Optic nerve </entry>
<entry linktype="AI" linkname="EUR-019-019" title="Figure 19.19: Retina, Choroid, and Part of the Sclera, Pig">Retina, Choroid, and Part of the Sclera, Pig. Note that the dendrites (cones) of cone cells of the pig are particularly plump and easily recognized. Blood vessel Cone Cone Ganglion cell layer Inner limiting membrane Pigment epithelium Outer plexiform layer Layer of rods and cones Sclera Outer nuclear layer Cone Blood vessel Inner nuclear layer Inner plexiform layer Rod Choroid Cone Nerve fiber layer </entry>
<entry linktype="AI" linkname="EUR-019-020" title="Figure 19.20: Fibrous Tapetum Lucidum, Sheep">Fibrous Tapetum Lucidum, Sheep. The tapetum lucidum of ruminants and horses is a compact membrane of connective tissue sandwiched between the choriocapillary and vascular layers of the choroid. The cells of the pigment epithelium of the retina contain few or no pigment granules where a tapetum lucidum is present. Compare with Figure 19.21. Outer nuclear layer Tapetum lucidum Vascular layer, choroid Choriocapillary layer Layer of rods and cones Pigment epithelium Melanocytes </entry>
<entry linktype="AI" linkname="EUR-019-021" title="Figure 19.21: Retina, Choroid, and Part of the Sclera, Dog">Retina, Choroid, and Part of the Sclera, Dog. Where the tapetum lucidum is lacking from the choroid layer, the cells of the pigment epithelium of the retina contain numerous melanosomes. Ganglion cell layer Vascular layer, choroid Pigment epithelium Inner plexiform layer Inner nuclear layer Outer plexiform layer Outer nuclear layer Layer of rods and cones Melanocytes Sclera Nerve fiber layer Ganglion cell layer Choriocapillary layer </entry>
<entry linktype="AI" linkname="EUR-019-022" title="Figure 19.22: Cellular Tapetum Lucidum, Dog">Cellular Tapetum Lucidum, Dog. In profile, the cells of the tapetum lucidum of carnivores are bricklike. Note that in this section the cells of the pigment epithelium of the retina are indistinct and lack pigment. Compare with Figure 19.21. Outer plexiform layer Pigment epithelium Layer of rods and cones Choriocapillary layer Inner nuclear layer Outer nuclear layer Tapetum lucidum Vascular layer, choroid Melanocytes Melanocytes </entry>
<entry linktype="AI" linkname="EUR-019-023" title="Figure 19.23: Melanocytes of Choroid Layer, Dog">Melanocytes of Choroid Layer, Dog. Melanocytes of the choroid layer are flat polygonal cells with cytoplasmic processes. Their polygonal shape is evident in this tangential cut through the choroid layer. Capillary, x.s. Cytoplasmic process Melanocytes Tapetal cell Tapetal cell </entry>
<entry linktype="AI" linkname="EUR-019-024" title="Figure 19.24: Tapetum Lucidum, Dog">Tapetum Lucidum, Dog. Tapetal cells are flattened and have a pentagonal or hexagonal outline, which is apparent in this tangential section through the choroid layer. The cells are filled with numerous small rods, whose long axes parallel the flat surfaces of the cells. Tapetal cell Tapetal cell Capillary, x.s. </entry>
<entry linktype="AI" linkname="EUR-019-025" title="Figure 19.25: Nictitating Membrane and Cornea, Horse">Nictitating Membrane and Cornea, Horse. A portion of the bulbar surface of the nictitating membrane and its supportive cartilage are shown. The nictitating membrane is a fold of the ventromedial portion of the conjunctiva. It contains elastic cartilage in the horse, pig, and cat, and hyaline cartilage in the dog and ruminants. Anterior chamber Descemet's membrane Pectinate ligament Cornea Nictitating membrane, bulbar surface Elastic cartilage Bulbar conjunctiva </entry>
<entry linktype="AI" linkname="EUR-019-026" title="Figure 19.26: Superficial Gland of the Nictitating Membrane, Dog">Superficial Gland of the Nictitating Membrane, Dog. The base of the cartilage of the nictitating membrane is surrounded by the superficial gland. Hyaline cartilage Duct Superficial gland Duct Diffuse lymphatic tissue </entry>
<entry linktype="AI" linkname="EUR-019-027" title="Figure 19.27: Superficial Gland of the Nictitating Membrane, Dog">Superficial Gland of the Nictitating Membrane, Dog. This gland is mixed in the dog and ruminants. It is serous in the horse and cat and mucous in the pig. Serous acinus Serous acinus Mucous acinus Hyaline cartilage Serous acinus </entry>
<entry linktype="AI" linkname="EUR-019-028" title="Figure 19.28: Palpebral Conjunctiva, Pig">Palpebral Conjunctiva, Pig. The palpebral conjunctiva is a mucous membrane that lines the inner surface of the eyelid. Its stratified epithelium varies from squamous through columnar and may even appear transitional. Goblet cells may be present. Stratified squamous epithelium Goblet cell Stratified columnar epithelium </entry>
<entry linktype="AI" linkname="EUR-019-029" title="Figure 19.29: Eyelid, Lower, Horse">Eyelid, Lower, Horse. The outer surface of the eyelid is covered by thin skin, while the inner surface is lined by the palpebral conjunctiva. The tarsal gland is a multilobulated gland whose duct opens onto the palpebral surface near the margin of the eyelid. The tarsal gland is surrounded by a condensed layer of connective tissue, the tarsus. Palpebral conjunctiva Duct Tarsus Tarsus Tarsal gland Tarsus Epidermis </entry>
<entry linktype="AI" linkname="EUR-019-030" title="Figure 19.30: Eyelid, Upper, Pig">Eyelid, Upper, Pig. Numerous tubular sweat glands (and sebaceous glands, not shown) occur in the skin surface of the eyelid of the pig.</entry>
<entry linktype="AI" linkname="EUR-019-032" title="Figure 19.32: Eyelid, Lower, Goat">Eyelid, Lower, Goat. Bundles of smooth and skeletal muscle fibers are scattered in the connective tissue between the tarsus and the skin surface of the eyelid. Tarsus Skeletal muscle tissue Skeletal muscle tissue Tarsal gland Smooth muscle tissue Tarsus Tarsus </entry>
<entry linktype="AI" linkname="EUR-019-033" title="Figure 19.33: Krause's Gland, Pig">Krause's Gland, Pig. Krause's gland is a small, accessory lacrimal gland (serous in this preparation) located near the fornix of the conjunctiva. Krause's gland Sclera Fornix of conjunctiva </entry>
<entry linktype="AI" linkname="EUR-019-034" title="Figure 19.34: Harderian Gland, Pig">Harderian Gland, Pig. Among domestic mammals, this gland is present only in the pig. It secretes a fatty product. Intralobular duct Acinus Acinus </entry>
<entry linktype="AI" linkname="EUR-019-035" title="Figure 19.35: Lacrimal Gland, Cow">Lacrimal Gland, Cow. A compound tubular acinar gland. The lacrimal gland is predominantly a serous gland in ruminants and horses. Acinus Interlobular connective tissue Acinus Interlobular connective tissue Intralobular duct </entry>
<entry linktype="AI" linkname="EUR-019-036" title="Figure 19.36: Eye, Drawing of an Anterolateral Segment, Chicken">Ciliary Process, Chicken (Masson's). Ciliary processes occur below the base of the iris and fuse with the lens capsule of the annular pad. The ciliary epithelium also attaches to the capsule by zonular fibers. Scleral cartilage Scleral ossicle Brucke's muscle Crampton's muscle Canal of Schlemm Scleral trabecular meshwork Pectinate ligament Ciliary body Cornea Anterior chamber Iris Posterior chamber Annular pad Lens body Cavity of vitreous humor Ciliary process Zonular fibers </entry>
<entry linktype="AI" linkname="EUR-019-037" title="Figure 19.37: Lens, Chicken">Ciliary Process, Chicken (Masson's). Ciliary processes occur below the base of the iris and fuse with the lens capsule of the annular pad. The ciliary epithelium also attaches to the capsule by zonular fibers. Capsule Lens fibers, annular pad Cavity of the lens Lens fibers, lens body </entry>
<entry linktype="AI" linkname="EUR-019-038" title="Figure 19.38: Filtration Angle, Chicken">Ciliary Process, Chicken (Masson's). Ciliary processes occur below the base of the iris and fuse with the lens capsule of the annular pad. The ciliary epithelium also attaches to the capsule by zonular fibers. Cornea Sclera Anterior chamber Scleral ossicle Scleral ossicle Canal of Schlemm Crampton's muscle Iris Pectinate ligament Spaces of Fontana Ciliary process Ciliary body Brucke's muscle Bulbar conjunctiva </entry>
<entry linktype="AI" linkname="EUR-019-039" title="Figure 19.39: Ciliary Process, Chicken (Masson's)">Ciliary Process, Chicken (MassonÕs). Ciliary processes occur below the base of the iris and fuse with the lens capsule of the annular pad. The ciliary epithelium also attaches to the capsule by zonular fibers. Nonpigmented epithelium, iris Zonular fibers Posterior chamber Sphincter muscle Dilator muscle Ciliary process Dilator muscle Pigmented epithelium, iris Sphincter muscle Capsule Posterior chamber Lens fibers, annular pad </entry>
<entry linktype="AI" linkname="EUR-019-040" title="Figure 19.40: Iris, Chicken">Iris, Chicken. The iridial musculature of the chicken is composed of skeletal muscle cells, which are characterized by the presence of numerous lipid vacuoles. Unlike mammals, the anterior (corneal) surface of the iris is covered by a layer of flattened, nonpigmented epithelial cells. The posterior (lens) surface of the iris (see Figure 19.39) is covered by a stratified pigmented epithelium that is three to five cells thick. Nonpigmented epithelium, iris Sphincter muscle cell Lipid vacuole Lipid vacuole Dilator muscle cell </entry>
<entry linktype="AI" linkname="EUR-019-041" title="Figure 19.41: Junction of Ciliary Body and Iris, Chicken (Orcein)">Junction of Ciliary Body and Iris, Chicken (Orcein). The elastic fibers of the pectinate ligament insert into an elastic meshwork of the ciliary body. Nonpigmented epithelium, iris Pectinate ligament Ciliary body Pigmented epithelium, iris Zonular fibers Zonular fibers </entry>
<entry linktype="AI" linkname="EUR-019-042" title="Figure 19.42: Pectinate Ligament, Chicken">Pectinate Ligament, Chicken. The elastic fibers of the pectinate ligament are covered by a simple squamous epithelium. Squamous cell, nucleus Elastic fiber </entry>
<entry linktype="AI" linkname="EUR-019-043" title="Figure 19.43: Cornea, Chicken">Cornea, Chicken. A well-developed Bowman's membrane separates the anterior, stratified squamous epithelium of the cornea from the underlying stroma. Stratified squamous epithelium Bowman's membrane Stroma Descemet's membrane Posterior epithelium Nonpigmented epithelium, iris </entry>
<entry linktype="AI" linkname="EUR-019-044" title="Figure 19.44: Sclera, Chicken">Sclera, Chicken. The sclera is strengthened anteriorly by overlapping bony plates (scleral ossicles). Posteriorly, it consists of a thin layer of cartilage. See Figure 19.36 for the location of ossicles and cartilage. The region of overlap of these skeletal elements is shown here. In this section the ciliary body has separated from the sclera, creating a space artifact. Scleral ossicle Scleral ossicle Scleral cartilage Space artifact </entry>
<entry linktype="AI" linkname="EUR-019-045" title="Figure 19.45: Retina and Choroid, Chicken">Retina and Choroid, Chicken. The bulk of the choroid is composed of blood vessels and large spaces supported by a loose connective tissue. The layers of the retina are comparable with those of mammals. Nerve fiber layer Ganglion cell layer Inner plexiform layer Inner nuclear layer Pigment epithelium Layer of rods and cones Outer plexiform layer Outer nuclear layer Blood vessels Loose connective tissue Space of choroid Loose connective tissue </entry>
<entry linktype="AI" linkname="EUR-019-046" title="Figure 19.46: Retina and Choroid, Chicken">Retina and Choroid, Chicken. Cells of the pigment epithelium of the retina are tall and contain rod-shaped pigment granules. The basal region of each cell contains the nucleus and a few pigment granules. Inner nuclear layer Outer plexiform layer Outer nuclear layer Layer of rods and cones Pigment epithelium Choriocapillary layer </entry>
<entry linktype="AI" linkname="EUR-019-047" title="Figure 19.47: Pecten, Chicken">Pecten, Chicken. The pecten is a thin, folded, and heavily pigmented membrane that projects into the vitreous humor from the posteroventral surface of the eye. Covering membrane Choroid Retina Bridge Pecten Optic nerve Scleral cartilage </entry>
<entry linktype="AI" linkname="EUR-019-048" title="Figure 19.48: Pecten, Chicken">Pecten, Chicken. Numerous, polymorphic melanocytes are interspersed through this highly vascularized, nutritive membrane. The large capillaries are lined by thick endothelial cells with plump nuclei. Melanocyte Capillary Capillary </entry>
<entry linktype="AI" linkname="EUR-019-049" title="Figure 19.49: Bridge of Pecten, Chicken">Bridge of Pecten, Chicken. This thickened, highly pigmented mass of pectineal tissue is located along the free edge of the pecten. Covering membrane Capillary Melanocyte Capillary </entry>
<entry linktype="AI" linkname="EUR-019-050" title="Figure 19.50: Eyelid, Chicken">Eyelid, Chicken. A thin epidermis covers the eyelid. Herbst corpuscles are associated with a feather follicle. Epidermis Dermis Herbst corpuscle Feather follicle Herbst corpuscle </entry>
<entry linktype="AI" linkname="EUR-019-051" title="Figure 19.51: Lacrimal Gland, Chicken">Lacrimal Gland, Chicken. This compound tubular gland produces a mucoid secretion and is organized into lobules. Collecting duct Secretory tubule Collecting duct Interlobular connective tissue Interlobular connective tissue Secretory tubule </entry>
<entry linktype="AI" linkname="EUR-019-052" title="Figure 19.52: Harderian Gland, Chicken">Harderian Gland, Chicken. This accessory immunologic gland contains a multitude of plasma cells. It is located on the dorsal posterior surface of the eye. Extrinsic muscle Scleral cartilage Harderian gland Choroid Retina Extrinsic muscle Plasma cells </entry>
<entry linktype="AI" linkname="EUR-019-053" title="Figure 19.53: Harderian Gland, Chicken">Harderian Gland, Chicken. Detail of the Harderian gland showing numerous plasma cells surrounding the vacuolated cells of the tubular secretory units. Secretory tubule Plasma cells Secretory tubule </entry>
<entry linktype="AI" linkname="EUR-020-001" title="Figure 20.1: External Auditory Meatus, Puppy">External Auditory Meatus, Puppy. The outer portion of the meatus is supported by elastic cartilage. The thin epidermis is underlain by numerous sebaceous glands and a few ceruminous glands. Small hair follicles are present. Sebaceous gland Elastic cartilage Ceruminous gland Hair follicle Epidermis Hair follicle </entry>
<entry linktype="AI" linkname="EUR-020-002" title="Figure 20.2: External Auditory Meatus, Puppy">External Auditory Meatus, Puppy. The external auditory meatus, near the tympanic membrane, contains large sebaceous glands. External auditory meatus Epidermis Duct Duct Ceruminous gland Sebaceous gland </entry>
<entry linktype="AI" linkname="EUR-020-003" title="Figure 20.3: External Auditory Meatus, Goat">External Auditory Meatus, Goat. The outer portion of the external auditory meatus with numerous ceruminous glands is shown. Hair follicles and portions of sebaceous glands are also present. Hair follicle Sebaceous gland Epidermis External auditory meatus Adipose tissue Ceruminous gland </entry>
<entry linktype="AI" linkname="EUR-020-004" title="Figure 20.4: Ceruminous Gland, Goat">Ceruminous Gland, Goat. The secretory epithelium of these apocrine glands varies from cuboidal to columnar. The cells contain tiny, brown pigment granules. Pigment granules Pigment granules </entry>
<entry linktype="AI" linkname="EUR-020-005" title="Figure 20.5: Tympanic Membrane, Periphery, Puppy">Tympanic Membrane, Periphery, Puppy. The tympanic membrane has a core of collagenous fibers. Its outer (external auditory meatus) surface is covered by a stratified squamous epithelium; its inner (tympanic cavity) surface is covered by a simple squamous or cuboidal epithelium. External auditory meatus Tympanic cavity Tympanic membrane Bone </entry>
<entry linktype="AI" linkname="EUR-020-006" title="Figure 20.6: Malleus and Tympanic Membrane, Puppy">Malleus and Tympanic Membrane, Puppy. The handle (manubrium) of the malleus is attached to the tympanic membrane. Tympanic membrane Tympanic cavity Ligament Incus External auditory meatus Malleus Tympanic cavity Ligament </entry>
<entry linktype="AI" linkname="EUR-020-007" title="Figure 20.7: Tympanic Membrane, Puppy">Tympanic Membrane, Puppy. Where the manubrium of the malleus is embedded in the tympanic membrane, the connective tissue of the tympanic membrane is thicker than elsewhere, and blood vessels are abundant. Malleus Tympanic membrane Tympanic cavity External auditory meatus </entry>
<entry linktype="AI" linkname="EUR-020-008" title="Figure 20.8: Portion of Stapes and Incus, Puppy">Portion of Stapes and Incus, Puppy. The footplate of the stapes is attached to the oval window by an annular ligament (broken on one side in this section). The stapes articulates with the lenticular process of the incus. Incus Lenticular process, articular cartilage Stapes, articular cartilage Tympanic cavity Facial nerve Temporal bone, petrous part Annular ligament Vestibule Temporal bone, petrous part Footplate, stapes Saccule, macula of Facial nerve Temporal bone, petrous part Annular ligament Utricle, macula of Vestibule </entry>
<entry linktype="AI" linkname="EUR-020-009" title="Figure 20.9: Joint, Malleus and Incus, Puppy">Joint, Malleus and Incus, Puppy. The head of the malleus articulates with the body of the incus in this synovial joint. Tympanic cavity Joint capsule with elastic fibers Incus Synovial cavity Malleus Tympanic cavity Articular cartilage </entry>
<entry linktype="AI" linkname="EUR-020-010" title="Figure 20.10: Junction of Lenticular Process and Stapes, Puppy">Junction of Lenticular Process and Stapes, Puppy. The stapes articulates with the lenticular process of the incus. See Figure 20.8 for orientation. Lenticular process, articular cartilage Stapes, articular cartilage </entry>
<entry linktype="AI" linkname="EUR-020-011" title="Figure 20.11: Annular Ligament, Stapes, Puppy">Annular Ligament, Stapes, Puppy. The stapes is fastened to the circular cartilage of the oval window by the fibroelastic, annular ligament. See Figure 20.8 for orientation. Temporal bone, petrous part Stapes, articular cartilage Annular ligament Temporal bone, petrous part </entry>
<entry linktype="AI" linkname="EUR-020-012" title="Figure 20.12: Macula of Saccule, Puppy">Macula of Saccule, Puppy. Otoliths are embedded in a gelatinous otolithic membrane, which lies on an epithelium consisting of sensory and supporting cells. Chalicelike, Type I sensory cells and the basal nuclei of supporting cells are evident in this micrograph. Supporting cell, nucleus Otolith Otolithic membrane Connective tissue Type 1 cell Supporting cell, nucleus </entry>
<entry linktype="AI" linkname="EUR-020-013" title="Figure 20.13: Crista Ampullaris, Puppy">Crista Ampullaris, Puppy. This ridge of sensory epithelium, supported by connective tissue, protrudes into the ampulla of a semicircular duct and is oriented at right angles to the long axis of the duct. The epithelium consists of sensory and supporting cells similar to those found in the maculae. A mass of gelatinous material, the cupula, covers the surface epithelium. Ampulla, cavity Supporting cell, nucleus Sensory cell, nucleus Cupula, portion of Connective tissue </entry>
<entry linktype="AI" linkname="EUR-020-014" title="Figure 20.14: Guttural Pouch, Horse">Guttural Pouch, Horse. This diverticulum of the Eustachian tube is lined by a ciliated, pseudostratified columnar epithelium with goblet cells. Mixed glands occur in the lamina propria. Pseudostratified epithelium Mixed glands </entry>
<entry linktype="AI" linkname="EUR-020-015" title="Figure 20.15: Cochlea, Puppy">Cochlea, Puppy. Cross section through a portion of the spiral cochlea. See Figure 20.16 for details of cochlear duct region. Modiolus Spiral ganglion Modiolus Scala tympani Scala vestibuli Temporal bone, petrous part Vestibular membrane Cochlear duct Spiral ligament Temporal bone, petrous part </entry>
<entry linktype="AI" linkname="EUR-020-016" title="Figure 20.16: Cochlear Duct in Cochlea, Puppy">Cochlear Duct in Cochlea, Puppy. Detail of the region of the cochlear duct (scala media, membranous cochlea) and surrounding temporal bone that forms the cochlea. Scala vestibuli Vestibular membrane Stria vascularis Temporal bone, petrous part Cochlear duct Tectorial membrane Spiral ligament Osseous spiral laminai Spiral limbus Spiral tunnel Organ of Corti Cochlear nerve Scala tympani Inner tunnel Basilar membrane </entry>
<entry linktype="AI" linkname="EUR-020-017" title="Figure 20.17: Semicircular Canal, x.s., Chicken">Semicircular Canal, x.s., Chicken. The semicircular canal is a part of the bony labyrinth. It contains the semicircular duct, a part of the membranous labyrinth. The duct is lined by a simple squamous epithelium except at the raphe, where cuboidal cells form the lining. Perilymphatic space Endolymphatic space Raphe Semicircular duct, wall Semicircular canal, wall Capillary </entry>
<entry linktype="AI" linkname="EUR-020-018" title="Figure 20.18: Cochlear Duct in Cochlea, x.s., Chicken (Masson's)">Cochlear Duct in Cochlea, x.s., Chicken (Masson's). Only a small portion of the bony cochlea that encloses the scala media is visible. The three passageways of the cochlea (the scala vestibuli, scala media, and scala tympani) are evident. The tegmentum vasculosum (see Figure 20.20) separates the scala vestibuli and the scala media. A portion of the organ of Corti is magnified in Figure 20.19. Cartilaginous frame, rostral Homogeneous cells Tegmentum vasculosum Scala vestibuli Tectorial membrane Scala media (cochlear duct) Organ of Corti Cochlear nerve Scala tympani Cartilaginous frame, caudal Cochlea </entry>
<entry linktype="AI" linkname="EUR-020-019" title="Figure 20.19: Organ of Corti, Cochlea, x.s., Chicken (Masson's)">Organ of Corti, Cochlea, x.s., Chicken (Masson's). The organ of Corti is composed of sensory cells and supporting cells with an overlying tectorial membrane. Tectorial membrane Scala media (cochlear duct) Hair cells Supporting cells Basilar membrane Scala tympani </entry>
<entry linktype="AI" linkname="EUR-020-020" title="Figure 20.20: Tegmentum Vasculosum, Cochlea, Chicken (Masson's)">Tegmentum Vasculosum, Cochlea, Chicken (Masson's). This thick membrane rests on a thin base of connective tissue and possesses a highly folded epithelial surface with numerous vascular loops. The epithelium consists of light and dark cells. Dark cells have a constricted neck region that extends to the surface of the epithelium. Their basal portion contains the nucleus and is irregularly shaped. The cytoplasm is very dense. Light cells have a pale cytoplasm and surround the dark cells. Scala vestibuli Blood vessel of connective tissue base Blood vessel of connective tissue base Blood vessel of connective tissue base Dark cell Scala media (cochlear duct) Light cell Homogeneous cells </entry>
