DEFINITION:The smallest of arteries connecting the arterial system to the capillary beds.
LINK:General Vasculature
TERM:Cardiac Cycle
DEFINITION:The repeating sequence of contractile events and valve openings and closures that results in the heart's ability to propel blood through the circulatory system.
LINK:Heart Dynamics
TERM:Cardiac Muscle
DEFINITION:Muscle of the heart, consisting of specialized striated cells. These cells are interconnected into a mass called the myocardium.
LINK:Histology of Cardiac Muscle
TERM:Conduction System
DEFINITION:A system of specialized muscle fibers that direct and time the flow of electrical activity through the heart muscle, resulting in a productive pumping action.
LINK:Heart Dynamics
TERM:Continuous Capillary
DEFINITION:A capillary with walls that contain no pores. Continuous capillaries are found in the endocrine glands, kidneys, and the small intestine.
LINK:General Vasculature
TERM:Diastole
DEFINITION:The period of time during which a heart chamber is relaxing.
LINK:Heart Dynamics
TERM:Einthovens Triangle
DEFINITION:A simplified model of the orientation of the limb leads within the frontal plane of the body.
LINK:Electrocardiogram
TERM:Electrocardiogram
DEFINITION:A graphic recording of the heart's electrical activity. An electrocardiogram is recorded by placing electrodes on the surface of the body.
LINK:Heart Dynamics
LINK: Electrocardiogram
TERM:Endothelium
DEFINITION:Innermost lining of vessels. Made up of endothelial cells.
LINK:General Vasculature
TERM:Fenestrated Capillary
DEFINITION:A capillary that contains pores in its walls. The pores are closed by a delicate membrane. Fenestrated capillaries are found in endocrine glands, kidneys, and the small intestine.
LINK:General Vasculature
TERM:Heart
DEFINITION:A muscular organ found in the thoracic cavity that pumps blood through the circulatory system.
LINK:Gross Anatomy of the Heart
TERM:Heart Murmur
DEFINITION:Abnormal heart sound produced by turbulent blood flow in the heart.
LINK:Heart Murmur
TERM:Heart Sounds
DEFINITION:Sounds produced by the heart during the cardiac cycle as a result of blood flow and valve closure events.
LINK:Heart Dynamics
TERM:Myocardial Infarction
DEFINITION:Loss of blood flow to a portion of the heart muscle due to the blockage of the supplying artery.
LINK:Myocardial Infarction
TERM:P-wave
DEFINITION:The first wave form in an electrocardiogram that results from depolarization of the atria.
LINK:Heart Dynamics
TERM:Portal System
DEFINITION:Refers to a vascular system that contains two capillary beds in series.
LINK:General Portal System
TERM:Precapillary Sphincter
DEFINITION:Smooth muscle cells that are oriented around the circumference of an arteriole. This sphincter regulates the flow of blood into the capillary bed fed by the arteriole.
LINK:General Vasculature
TERM:QRS-wave
DEFINITION:The second wave form in an electrocardiogram that results from the depolarization of the ventricles.
LINK:Heart Dynamics
TERM:Systole
DEFINITION:The period of time during which a heart chamber is contracting.
LINK:Heart Dynamics
TERM:T-wave
DEFINITION:The third wave form in an electrocardiogram, which results from the repolarization of the ventricles.
LINK:Heart Dynamics
TERM:Tunica Adventitia
DEFINITION:The outermost layer of a vessel. It is in contact with the surrounding connective tissue.
LINK:General Vasculature
TERM:Tunica Intima
DEFINITION:The innermost layer of a vessel. The tunica intima contains the endothelium and often an internal elastic layer.
LINK:General Vasculature
TERM:Tunica Media
DEFINITION:The middle layer of a vessel. The tunica media usually contains muscular elements.
LINK:General Vasculature
TERM:Valve
DEFINITION:One-way valve found in the body's venous system that assists in the return of blood to the heart. Since blood pressure is low on the venous side of the circulatory system, a valve ensures that blood does not flow backward, but can only advance toward the heart.
LINK:General Vasculature
TERM:Valvular Insufficiency
DEFINITION:A condition in which the seal formed when a valve closes is defective and allows blood to backflow.
LINK:Heart Murmur
TERM:Valvular Stenosis
DEFINITION:A condition in which the lumen formed when a heart valve is open is abnormally small.
LINK:Heart Murmur
TERM:Venule
DEFINITION:The smallest vein that connects the venous side of a capillary bed to a larger vein.
LINK:General Vasculature
TERM:Abdomen
DEFINITION:The portion of the trunk that lies above the pelvis and below the thorax.
LINK:Abdomen
TERM:Absorption
DEFINITION:The taking in of substances by cells or membranes.
LINK:Duodenum
TERM:Acetylcholine
DEFINITION:A neurotransmitter that is secreted at the axon ends of many neurons. It is the neurotransmitter released from motor neurons at the neuromuscular junction.
LINK:Neuromuscular Junction
TERM:Actin
DEFINITION:A structural protein found in muscle that, along with myosin, is responsible for muscle contraction.
LINK:Cardiac Muscle Anatomy
LINK:Skeletal Muscle Anatomy
LINK:Sliding Filament Theory
TERM:Action Potential
DEFINITION:An all-or-none electrical depolarization of the cell membrane that occurs in neurons and muscular cells. It allows for rapid signal transmission down the nerve axons and in muscles.
LINK:Neuromuscular Junction
TERM:Adrenal Cortex
DEFINITION:The adrenal cortex secretes steroid hormones involved in sodium regulation and the stress response, most prominently aldosterone and cortisol.
LINK:Adrenal Gland
LINK:Histology of Adrenal Cortex
LINK:Histology of Adrenal Medulla
TERM:Adrenal Gland
DEFINITION:The adrenal gland is two endocrine organs in one. The cortex and medulla of the adrenal gland act as independent organs, each secreting their own hormones.
LINK:Adrenal Gland
LINK:Endocrine Anatomy
TERM:Adrenal Medulla
DEFINITION:The adrenal medulla secretes the catecholamine hormones epinephrine and norepinephrine.
LINK:Adrenal Gland
LINK:Histology of Adrenal Medulla
TERM:AIDS
DEFINITION:Acquired Immunodeficiency Syndrome is the disease that results from infection with the HIV virus.
LINK:HIV / AIDS
TERM:Alpha Cell
DEFINITION:A cell type found within the pancreatic islet. It secretes glucagon into the blood when glucose levels are low.
LINK:Diabetes
TERM:Alveolus
DEFINITION:An air sac found in the lungs. It is the site of gas exchange.
LINK:Gas Exchange
LINK:Histology of Alveoli
LINK:Histology of Bronchiole
LINK:Histology of Lung
LINK:Respiratory Anatomy
TERM:Anal Canal
DEFINITION:The most distal two or three inches of the large intestine that open to the outside as the anus.
LINK:Digestive Anatomy
TERM:Antagonist
DEFINITION:A muscle or effector molecule that counteracts the action of another.
LINK:Muscle Action Around Joints
TERM:Anterior
DEFINITION:A structure that is closer to the front of the body than another structure is anterior. The eyes are anterior to the brain.
LINK:Directional Terminology
TERM:Anterior Lobe of the Pituitary Gland
DEFINITION:The anterior lobe of the pituitary gland contains a variety of hormone-secreting cells that are regulated by the releasing hormones of neurosecretory cells in the hypothalamus.
LINK:Hypothalamus and Pituitary Gland
TERM:Antibody
DEFINITION:A protein that B-cells of the immune system produce in response to the presence of a non-self antigen. The antibody can then bind to that antigen.
LINK:Antibody-Mediated Immunity
LINK:Blood Type
LINK:Microscopic Components
LINK:Vaccination
TERM:Antigen
DEFINITION:A molecule that stimulates immune cells to produce antibodies.
LINK:Antibody-Mediated Immunity
LINK:Cytotoxic T-Cell Function
LINK:Microscopic Components
LINK:Phagocytosis
LINK:T-Helper Cell Function
LINK:Vaccination
TERM:Antigen Presenting Cell
DEFINITION:A cell that presents antigens on its surface to cells of the immune system.
LINK:Microscopic Components
LINK:T-Helper Cell Function
TERM:Antigenic Determinant
DEFINITION:The small portion of an antigen that a specific antibody against that antigen recognizes.
LINK:
TERM:Anus
DEFINITION:The inferior outlet of the digestive tube.
LINK:Digestive Anatomy
TERM:Appendix
DEFINITION:A small, tubular appendage that extends outward from the cecum of the large intestine.
LINK:Digestive Anatomy
TERM:Articular Cartilage
DEFINITION:Hyaline cartilage that covers the articulating surfaces of bones in a synovial joint.
LINK:Histology of Synovial Joint
LINK:Synovial Joint
TERM:Asthma
DEFINITION:A chronic respiratory disease characterized by difficult breathing due to constricted airways.
LINK:
TERM:Axon
DEFINITION:A nerve fiber that conducts a nerve impulse away from a neuron cell body.
LINK:Neuromuscular Junction
TERM:Axon Terminal
DEFINITION:The specialized end of an axon. The site where neurotransmitter-release occurs.
LINK:Neuromuscular Junction
TERM:B-Lymphocyte
DEFINITION:The type of lymphocyte that reacts to foreign substances in the body by producing and secreting antibodies.
LINK:Antibody-Mediated Immunity
LINK:Microscopic Components
LINK:T-Helper Cell Function
TERM:Bile
DEFINITION:Fluid secreted by the liver and stored in the gallbladder.
LINK:Gallstones
LINK:Gallbladder and Liver
TERM:Beta Cell
DEFINITION:A cell type found within the pancreatic islet. It secretes insulin into the blood when glucose levels are high.
LINK:Diabetes
TERM:Blood Type
DEFINITION:Typically refers to the presence of antigens on the red blood cell's surface called A and B. A person can have A, B, both A and B, or neither of these antigens. When neither surface antigen is present, the blood is type O.
LINK:Blood Type
TERM:Bone Marrow
DEFINITION:Soft connective tissue in the core of a bone. Bone marrow produces red blood cells.
LINK:Cross Section of a Long Bone
LINK:Histology of Spongy Bone
LINK:Histology of Synovial Joint
TERM:Boyle's Law
DEFINITION:Formulated by Robert Boyle (1622-1691). Simply stated, at a fixed temperature the pressure of an ideal gas varies inversely with its volume.
LINK:Boyle's Law
LINK:Mechanics of Breathing
TERM:Bronchiole
DEFINITION:A small-diameter, thin-walled extension of the bronchus. It carries air to the alveoli.
LINK:Histology of Bronchiole
LINK:Histology of Lung
LINK:Respiratory Anatomy
TERM:Bronchoscopy
DEFINITION:The process of examining the bronchi with a bronchoscope.
LINK:Bronchoscopy
TERM:Bronchus
DEFINITION:Branch of the trachea that carries air into the lungs.
LINK:Respiratory Anatomy
TERM:Brush Border
DEFINITION:Refers to the brush-like appearance of the lumen side of epithelial cells within the small intestine because of the layer of microvilli.
LINK:Histology of Duodenal Villi
TERM:Bursa
DEFINITION:Synovial, fluid-filled sac. Usually found at points where tendons contact bones.
LINK:Synovial Joint
TERM:Calyx
DEFINITION:Extension of the renal pelvis. Collecting ducts empty newly-formed urine into renal calyces.
LINK:Kidney Anatomy
LINK:Urine Formation
LINK:Histology of the Renal Calyx
TERM:Collecting Duct
DEFINITION:In the kidneys, a straight tubule that receives fluid from several nephrons.
LINK:Kidney Anatomy
LINK:Nephron Anatomy
LINK:Urine Formation
TERM:Carbohydrate
DEFINITION:An organic compound that contains carbon, hydrogen, and oxygen, with a 2:1 ratio of hydrogen to oxygen atoms.
LINK:Duodenum
LINK:Pancreas
TERM:Cartilagenous Joint
DEFINITION:A joint that connects two bones with solid cartilage.
LINK:Cartilagenous Joint
TERM:Cecum
DEFINITION:A pouch-like portion of the large intestine attached to the small intestine.
LINK:Digestive Anatomy
TERM:Central Canal
DEFINITION:Cerebrospinal, fluid-filled canal in the middle of the spinal cord. It is a continuation of the brain's ventricular system.
LINK:Spinal Cord Anatomy
TERM:Central Nervous System
DEFINITION:The portion of the nervous system found within the axial skeleton. The central nervous system includes the brain and spinal cord.
LINK:Nervous System
TERM:Cerebral Cortex
DEFINITION:Outer mantle of the brain. The cerebral cortex is divided into gyri and sulci.
LINK:Gross Anatomy of the Brain
LINK:Stroke
TERM:Chemically Gated Ion Channel
DEFINITION:An ion channel that controls the flow of ions across a cell's membrane. Its opening and closing is regulated by a chemical signal, usually a neurotransmitter or hormone.
LINK:Neuromuscular Junction
TERM:Chemotaxis
DEFINITION:Attraction of leukocytes to chemicals released from damaged cells.
LINK:
TERM:Chylomicron
DEFINITION:A microscopic droplet of fat in the blood following fat digestion.
LINK:Duodenum
TERM:Cisternae
DEFINITION:Enlarged portion of the sarcoplasmic reticulum near the actin and myosin filaments of a muscle fiber. The cisternae serve as a calcium bank.
LINK:Anatomy of Cardiac Muscle
LINK:Anatomy of Skeletal Muscle
TERM:Colon
DEFINITION:The large intestine.
LINK:Digestive Anatomy
TERM:Common Bile Duct
DEFINITION:A tube that carries bile from the cystic duct to the duodenum.
LINK:Gallbladder and Liver
LINK:Pancreas
TERM:Compact Bone
DEFINITION:Dense bone that is superficial to the bone marrow and covered by the periosteum.
LINK:Cross Section of a Long Bone
LINK:Histology of Compact Bone
TERM:Cone
DEFINITION:Sensory cell found in the retina that transduces light into electrical energy. Cones are sensitive to either red-, green-, or blue-colored light.
LINK:Vision
TERM:Contralateral
DEFINITION:Two structures that are on opposite sides of the body are contralateral. The left arm and right leg are contralateral.
LINK:Directional Terminology
TERM:Coronal (Frontal) Plane
DEFINITION:Divides the body into anterior and posterior portions.
LINK:Planes
TERM:Corpus Albicans
DEFINITION:The fibrous remnant of a corpus luteum.
LINK:Ovarian Cycle
TERM:Corpus Callosum
DEFINITION:A large tract that connects the left and right cerebral hemispheres.
LINK:Gross Anatomy of the Brain
TERM:Corpus Luteum
DEFINITION:A structure that forms from the tissues of a ruptured ovarian follicle. It functions to secrete female hormones, mainly progesterone.
LINK:Histology of Ovarian Follicle
LINK:Ovarian Cycle
TERM:Crista Ampullaris
DEFINITION:The vestibular organ that measures rotational acceleration at the head.
LINK:Dynamic Equilibrium
TERM:Cystic Duct
DEFINITION:The tube that connects the gallbladder to the common bile duct.
LINK:Gallbladder and Liver
TERM:Cytokine
DEFINITION:A type of protein secreted by a T-lymphocyte when it attacks viruses, virally infected cells, and cancer cells.
LINK:Microscopic Components
TERM:Cytotoxic T-Lymphocyte
DEFINITION:A cell that recognizes non-self antigens on cancerous cells or virally infected cells. When an antigen is recognized, the cytotoxic T-cell proliferates and kills the abnormal cell.
LINK:
TERM:Deep
DEFINITION:A structure that is closer to the core of the body than another is deep. The brain is deep to the skull.
LINK:Directional Terminology
TERM:Delta Cell
DEFINITION:A cell type found within the pancreatic islet. It secretes somatostatin into the blood.
LINK:Diabetes
TERM:Dendrite
DEFINITION:Input fiber of a neuron.
LINK:
TERM:Diabetes (mellitus)
DEFINITION:The appearance of glucose in the urine due to the presence of high plasma glucose concentrations, even in the fasting state. This disease is caused by either a lack of sufficient insulin secretion (type I) or by an inadequate responsiveness of the target tissues to the effects of insulin secretion (type II).
LINK:Diabetes
TERM:Diaphragm
DEFINITION:The muscle that forms the lower border of the thoracic cavity. Its contraction expands the thoracic cavity during inspiration.
LINK:Mechanics of Breathing
TERM:Distal
DEFINITION:A structure that is farther from a body part's origin than another structure is distal. The elbow is distal to the shoulder.
LINK:Directional Terminology
TERM:Distal Convoluted Tubule
DEFINITION:A tortuous portion of the renal tubule that carries fluid away from the collecting duct.
LINK:Nephron Anatomy
LINK:Urine Formation
TERM:Dorsal Root Ganglion
DEFINITION:A ganglion situated in the dorsal root where the cell bodies of somatic sensory neurons are located.
LINK:Spinal Cord Anatomy
TERM:Edema
DEFINITION:Accumulation of fluid in the tissue spaces.
LINK:
TERM:Elastic Cartilage
DEFINITION:Cartilage that contains proteinaceous elastic fibers within its matrix.
LINK:Histology of Elastic Cartilage
TERM:Emphysema
DEFINITION:A disease of the lungs resulting from a decrease in number and an increase in size of the alveoli. This results in a smaller surface area for gas exchange.
LINK:
TERM:Emulsification
DEFINITION:The breaking up of fat globules into smaller droplets by the action of bile salts.
LINK:Gallbladder and Liver
TERM:Endometrium
DEFINITION:The mucous membrane of the uterus. Its thickness and structure vary throughout the menstrual cycle.
LINK:Menstruation
TERM:Endomysium
DEFINITION:The sheath of connective tissue surrounding each skeletal muscle fiber.
LINK:Anatomy of Skeletal Muscle
LINK:Histology of Skeletal Muscle - Longitudinal
LINK:Sliding Filament Theory
TERM:Endotoxin
DEFINITION:Some cell wall antigens of gram-negative bacteria have non-specific toxic effects on a variety of body systems.
LINK:
TERM:Enzyme
DEFINITION:A protein that catalyzes a specific chemical reaction. Pepsin and amylose are examples of enzymes.
LINK:Stomach
LINK:Duodenum
LINK:Pancreas
TERM:Epiglottis
DEFINITION:A cartilaginous structure that covers the glottis during swallowing so that food or drink does not enter the respiratory tract.
LINK:Respiratory Anatomy
TERM:Epimysium
DEFINITION:The outer sheath of connective tissue surrounding a skeletal muscle.
LINK:Anatomy of Skeletal Muscle
LINK:Sliding Filament Theory
TERM:Erection
DEFINITION:The process of penile stiffening due to the engorgement of its cavernous tissues with blood.
LINK:Erection
TERM:Esophagus
DEFINITION:A tubular portion of the digestive tract that leads from the pharynx to the stomach.
LINK:Digestive Anatomy
TERM:Expiratory Reserve Volume
DEFINITION:The volume of air that can be expired, in addition to the tidal volume, during forced maximal expiration (1100 ml).
LINK:Spirometry
TERM:Extension
DEFINITION:Movement that increases the angle between the parts of a joint.
LINK:Muscle Action Around Joints
LINK:Synovial Joint Motion
TERM:Fascicle
DEFINITION:A small bundle of muscle fibers.
LINK:Skeletal Muscle Anatomy
TERM:Fat
DEFINITION:An organic substance whose molecules contain glycerol and fatty acids.
LINK:Duodenum
LINK:Gallbladder and Liver
LINK:Pancreas
TERM:Fibrocartilage
DEFINITION:Cartilage that contains collagen fibers within its matrix.
LINK:Histology of Fibrocartilage
TERM:Fibrous Joint
DEFINITION:A joint that connects two bones with fibrous connective tissue.
LINK:Fibrous Joint
TERM:Filtrate
DEFINITION:The substance produced from forcing a material through a membrane as a result of hydrostatic pressure.
LINK:Urine Formation
TERM:Flexion
DEFINITION:Movement that decreases the angle between the parts at a joint.
LINK:Muscle Action Around Joints
LINK:Synovial Joint Motion
TERM:Follicle Stimulating Hormone (FSH)
DEFINITION:A gonadotropic hormone secreted by the anterior pituitary. In females, it stimulates the development of ovarian follicles. In males, FSH stimulates the production of sperm.
LINK:Ovarian Cycle
TERM:Functional Residual Capacity
DEFINITION:The expiratory reserve volume plus the residual volume (2300 ml).
LINK:Spirometry
TERM:Gallbladder
DEFINITION:Sac-like organ associated with the liver that stores and concentrates bile.
LINK:Digestive Anatomy
LINK:Gallstones
LINK:Gallbladder and Liver
LINK:Histology of the Gallbladder
TERM:Gastric Gland
DEFINITION:Gland found within the stomach wall that secretes gastric juice.
LINK:Stomach
LINK:Histology of Fundic Stomach
TERM:Gastric Juice
DEFINITION:Secretion of the gastric glands within the stomach.
LINK:Ulcer
LINK:Stomach
TERM:Gastric Pit
DEFINITION:A pit-like opening found in the stomach mucosa into which the gastric glands empty.
LINK:Stomach
LINK:Histology of Fundic Stomach
TERM:Glomerulus
DEFINITION:A tuft of capillaries located within the glomerular capsule of a nephron.
LINK:Nephron Anatomy
LINK:Urine Formation
LINK:Histology of the Renal Cortex
TERM:Glucagon
DEFINITION:A polypeptide hormone that is secreted by the alpha cells of the pancreatic islets. It promotes glycogenolysis to raise the blood glucose level.
LINK:Diabetes
TERM:Goblet Cell
DEFINITION:An epithelial cell that is specialized to secrete mucus.
LINK:Histology of Duodenal Villi
TERM:Granulosa Cell
DEFINITION:Cell found within the ovarian follicle. Granulosa cells surround the oocyte and secrete estrogen.
LINK:Histology of Ovarian Follicles
LINK:Oogenesis
LINK:Ovarian Cycle
TERM:Hair Cell
DEFINITION:A sensory cell that transduces mechanical energy to electrical energy.
LINK:Dynamic Equilibrium
TERM:Head
DEFINITION:The superior-most structure of the body. It houses the brain and major sense organs.
LINK:Head
TERM:Hemoglobin
DEFINITION:The oxygen-carrying protein found in red blood cells.
LINK:Oxygen Transport
TERM:Hepatic Duct
DEFINITION:A tube that carries bile from the liver to the cystic duct.
LINK:Gallbladder and Liver
TERM:Hepatocyte
DEFINITION:A liver cell.
LINK:Histology of the Liver
TERM:HIV
DEFINITION:Human Immunodeficiency Virus, a retrovirus which causes AIDS by attacking T-helper lymphocytes and other important immune cells.
LINK:HIV / AIDS
TERM:Hormone
DEFINITION:A regulatory chemical secreted into the blood by endocrine cells and carried by the blood to target cells.
LINK:Endocrine Function
TERM:Hyaline Cartilage
DEFINITION:A cartilage with a smooth homogeneous matrix.
LINK:Histology of Hyaline Cartilage
LINK:Histology of Nasal Cavity
TERM:Hypothalamo-Hypophyseal Portal System
DEFINITION:A specialized vascular system that delivers blood from the hypothalamus directly to the pituitary gland. It delivers releasing factors from the hypothalamus to the anterior lobe of the pituitary gland.
LINK:Hypothalamus and Pituitary Gland
TERM:Hypothalamo-Hypophyseal Tract
DEFINITION:A bundle of axons that come from specialized oxytocin or antidiuretic hormone (ADH) secreting neurons in the hypothalamus. These axons go directly to the posterior (neural) lobe of the pituitary, where oxygen and ADH are released into the blood.
LINK:Hypothalamus and Pituitary Gland
TERM:Hypothalamus
DEFINITION:A brain region that lies below the thalamus. The hypothalamus is an automatic center and regulates the pituitary gland.
LINK:Gross Anatomy of the Brain
TERM:Immunoglobulin
DEFINITION:Antibody.
LINK:
TERM:Inferior
DEFINITION:A structure that is below another structure is inferior. The abdomen is inferior to the thorax.
LINK:Directional Terminology
TERM:Inflammation
DEFINITION:A tissue response to stress or injury that is characterized by dilation of blood vessels and an accumulation of fluid in the affected region.
LINK:Inflammation
TERM:Infundibulum
DEFINITION:The stalk that connects the pituitary to the hypothalamus.
LINK:Histology of Pituitary Gland
LINK:Hypothalamus and Pituitary Gland
TERM:Inspiratory Reserve Volume
DEFINITION:The volume of air that can be inspired, in addition to the tidal volume, during forced maximal inspiration (3000 ml).
LINK:Spirometry
TERM:Insulin
DEFINITION:A polypeptide hormone that is secreted by the beta cells of the pancreatic islets. It promotes the cellular uptake of glucose from the blood, thus, lowering blood glucose levels.
LINK:Diabetes
TERM:Intercalated Disc
DEFINITION:Membranous boundary between adjacent cardiac muscle cells.
LINK:Cardiac Muscle Anatomy
LINK:Histology of Cardiac Muscle
TERM:Intercostal Muscle
DEFINITION:Muscle located between the ribs. Its contraction expands the thoracic cavity during inspiration.
LINK:Mechanics of Breathing
TERM:Interferon
DEFINITION:A class of immune system chemicals (cytokines) that inhibit the multiplication of viruses and the growth of tumors.
LINK:Interferon
TERM:Ipsilateral
DEFINITION:Two structures that are on the same side of the body are ipsilateral. The left arm and left leg are ipsilateral.
LINK:Directional Terminology
TERM:Isometric Contraction
DEFINITION:Muscular contraction in which tension is formed, but the muscle fails to shorten.
LINK:Isometric vs. Isotonic Contraction
TERM:Isotonic Contraction
DEFINITION:Muscular contraction in which the muscle shortens.
LINK:Isometric vs. Isotonic Contraction
TERM:Kidney
DEFINITION:The organ responsible for the filtration of blood to form urine.
LINK:Gross Anatomy
LINK:Histology of the Renal Calyx
LINK:Kidney Anatomy
TERM:Juxtaglomerular Apparatus
DEFINITION:A structure located in the walls of arterioles near the glomerulus that regulates renal blood flow.
LINK:Histology of the Renal Cortex
TERM:Lacteal
DEFINITION:A lymphatic capillary associated with a villus in the small intestine.
LINK:Duodenum
TERM:Large Intestine
DEFINITION:The portion of the gastrointestinal tract extending from the ileum to the anus. It is divided into the cecum, colon, rectum, and anal canal.
LINK:Barium Radiograph
LINK:Digestive Anatomy
TERM:Larynx
DEFINITION:The portion of the respiratory tract between the pharynx and trachea. It is made up of a complex combination of cartilagenous structures and houses the vocal folds.
LINK:Respiratory Anatomy
TERM:Lateral
DEFINITION:A structure that is farther from an imaginary midsagittal plane than another structure is lateral. The lungs are lateral to the heart.
LINK:Directional Terminology
TERM:Leg
DEFINITION:The lower extremity.
LINK:Leg
TERM:Ligament
DEFINITION:A tough, connective tissue cord that connects bone to bone.
LINK:Synovial Joint
TERM:Lingual Papilla
DEFINITION:Specialized elevation on the surface of the tongue. Many lingual papillae have taste buds.
LINK:Taste
TERM:Liver
DEFINITION:A large, dark-red organ in the upper abdomen that detoxifies blood, stores glycogen and fat soluble vitamins, and synthesizes proteins.
LINK:Digestive Anatomy
LINK:Gallbladder and Liver
LINK:Histology of the Gallbladder
LINK:Histology of the Liver
TERM:Lung
DEFINITION:Organ of respiration that occupies the thoracic cavity along with the heart.
LINK:Histology of Lung
LINK:Respiratory Anatomy
TERM:Luteinizing Hormone (LH)
DEFINITION:A gonadotropic hormone secreted by the anterior pituitary. In females, it stimulates ovulation and corpus luteum development. In males, LH stimulates testosterone secretion from the testis.
LINK:Ovarian Cycle
TERM:Lymph
DEFINITION:Fluid transported by the lymphatic system. It is drained from the tissue spaces.
LINK:Lymph Formation and Movement
TERM:Lymph Node
DEFINITION:A mass of lymphoid tissue located along the course of a lymphatic vessel. A site where lymph is exposed to cells of the immune system.
LINK:Immune Anatomy
LINK:Lymph Formation and Movement
LINK:Lymph Node
LINK:Peyer's Patches
TERM:Lymphocyte
DEFINITION:A type of white blood cell that provides specific immunity.
LINK:Fever
LINK:Microscopic Components
LINK:Phagocytosis
LINK:T-Helper Cell Function
LINK:Vaccination
TERM:Macrophage
DEFINITION:A large phagocytic cell.
LINK:Microscopic Components
LINK:Phagocytosis
TERM:Macula
DEFINITION:The vestibular organ that senses head position.
LINK:
TERM:Mast Cell
DEFINITION:A cell that releases several chemical signals including histamine during an allergic response.
LINK:Inflammation
LINK:Microscopic Components
TERM:Mature Sperm
DEFINITION:The male reproductive cell.
LINK:Spermatogenesis
TERM:Medial
DEFINITION:A structure that is closer to an imaginary midsagittal plane than another structure is medial. The sternum is medial to the ribs.
LINK:Directional Terminology
TERM:Medulla Oblongata
DEFINITION:The portion of the brainstem between the spinal cord and pons.
LINK:Gross Anatomy of the Brain
TERM:Memory Cell
DEFINITION:A B-lymphocyte or T-lymphocyte produced in an immune response that remains dormant and can be activated rapidly if the same antigen is encountered in the future.
LINK:Antibody-Mediated Immunity
LINK:Microscopic Components
LINK:Vaccination
TERM:Meniscus
DEFINITION:Crescent-shaped fibrocartilage bushing found in some synovial joints.
LINK:Histology of Synovial Joint
LINK:Synovial Joint
TERM:Menstruation
DEFINITION:The shedding of the outer two-thirds of the endometrium with accompanying bleeding due to the lowering of estrogen at the end of the monthly cycle.
LINK:Menstrual Cycle
TERM:Microvilli
DEFINITION:Microscopic cylindrical processes that extend from some epithelial cell membranes and dramatically increase the surface area of the cell.
LINK:Duodenum
TERM:Midsagittal (Median) Plane
DEFINITION:Divides the body into equally-sized right and left halves.
LINK:Planes
TERM:Motor End Plate
DEFINITION:Specialized portion of a muscle fiber membrane at a neuromuscular junction.
LINK:Histology of Neuromuscular Junction
TERM:Motor Neuron
DEFINITION:A neuron that transmits impulses from the central nervous system to an effector.
LINK:Neuromuscular Junction
TERM:Moveable Joint
DEFINITION:An articulation of bones capable of movement.
LINK:
TERM:Muscle Fiber
DEFINITION:Muscle cell.
LINK:Histology of Neuromuscular Junction
LINK:Histology of Skeletal Muscle - Cross Section
LINK:Sliding Filament Theory
LINK:Smooth Muscle Anatomy
TERM:Muscularis
DEFINITION:A layer of smooth muscle found in hollow organs.
LINK:Smooth Muscle Anatomy
TERM:Myocardium
DEFINITION:Muscle tissue of the heart.
LINK:Cardiac Muscle Anatomy
TERM:Myofibril
DEFINITION:Contractile fiber within muscle cells
LINK:Cardiac Muscle Anatomy
LINK:Skeletal Muscle Anatomy
LINK:Sliding Filament Theory
TERM:Myosin
DEFINITION:A protein that, together with actin, produces muscular contraction.
LINK:Sliding Filament Theory
TERM:Nasal Cavity
DEFINITION:The space between the nostrils and the nasopharynx.
LINK:Histology of Nasal Cavity
LINK:Respiratory Anatomy
TERM:Nephron
DEFINITION:The functional unit of the kidney, consisting of a renal corpuscle and a renal tubule.
LINK:Kidney Anatomy
LINK:Nephron Anatomy
LINK:Urine Formation
TERM:Nephron Loop
DEFINITION:A loop of the renal tubule that dips into the renal medulla. A nephron loop has a descending and an ascending limb.
LINK:Histology of the Renal Medulla
LINK:Nephron Anatomy
LINK:Urine Formation
TERM:Negative Feedback
DEFINITION:Mechanisms in the body that act to maintain a state of internal stability, or homeostasis. Effectors are activated by changes in the internal environment. The action of these effectors then counteracts these changes to maintain a state of balance.
LINK:Hypothalamo - Pituitary Thyroid Axis
TERM:Nerve Fiber
DEFINITION:Fibrous projection from a nerve. It can be either an axon or a dendrite.
LINK:Histology of Neuromuscular Junction
LINK:Neuromuscular Junction
TERM:Neurolemmocyte
DEFINITION:A glia cell type found in the peripheral nervous system that provides myelin insulation to nerve fibers. Neurolemmocytes are also known as Schwann cells.
LINK:Spinal Cord Anatomy
TERM:Neuromuscular Junction
DEFINITION:The point of contact between a motor neuron and a muscle cell.
LINK:Histology of Neuromuscular Junction
LINK:Neuromuscular Junction
TERM:Neuron
DEFINITION:The basic cellular unit of the nervous system.
LINK:
TERM:Neurosecretory Cell
DEFINITION:Specialized neuron that releases its "neurotransmitter" as a hormone into the blood.
LINK:Hypothalamus and Pituitary Gland
TERM:Neutrophil
DEFINITION:A type of phagocytic white blood cell.
LINK:
TERM:Nissl Substance
DEFINITION:Dark, stained clumps of rough endoplasmic reticulum found in neurons.
LINK:Spinal Cord Histology
TERM:Non-Specific Immunity
DEFINITION:Mechanisms such as fever and phagocytosis that non-specifically remove foreign substances.
LINK:Fever
LINK:Inflammation
LINK:Interferon
LINK:Phagocytosis
TERM:Olfactory Bulb
DEFINITION:A brain structure found between the frontal cortex and the nasal cavity. The olfactory bulb receives information from the olfactory epithelium.
