{target cell}{}{Specific cell upon which a hormone exerts its effect.}

{telophase}{}{Time during cell division when the chromosomes are pulled by spindle fibers away from the cell equator and into the two halves of the dividing cell.}

{temporal summation}{}{Summation of the local potential that results when two or more action potentials arrive at a single synapse in rapid succession.}

{tendon}{}{Band or cord of dense connective tissue that connects a muscle to a bone or other structure.}

{terminal cisterna [cisternae]}{}{Enlarged end of the sarcoplasmic reticulum in the area of the T tubules.}

{testosterone}{}{Steroid hormone secreted primarily by the testes; aids in spermatogenesis, maintenance and development of male reproductive organs, secondary sexual characteristics, and sexual behavior.}

{thalamus}{}{Large mass of gray matter that forms the larger dorsal subdivision of the diencephalon.}

{thermoreceptors}{}{Sensory receptor sensitive to temperature changes; heat and cold receptors.}

{threshold potential}{}{Value of the membrane potential at which an action potential is produced as a result of depolarization in response to a stimulus.}

{thymine}{}{One of four nucleotides found in DNA; abbreviated "T"; replaced with uracil in RNA.}

{thyroid gland}{}{Endocrine gland located inferior to the larynx and consisting of two lobes connected by the isthmus; secretes the thyroid hormones triiodothyronine [TÓ] and tetraiodothyronine [TÔ].}

{tissue}{}{A group of similar cell types working together as a functional unit.}

{trabecula [trabeculae]}{}{One of the supporting bundles of fibers traversing the substance of a structure, usually derived from the capsule or one of the fibrous septa, such as trabeculae of lymph nodes, testes; a beam or plate of cancellous bone.}

{trachea}{}{Tubular organ that leads from larynx to bronchi.}

{transcription}{}{Process of forming RNA from a DNA template.}

{transfer RNA [tRNA]}{}{RNA that attaches to individual amino acids and transports them to the ribosomes where they are connected to form a protein polypeptide chain.}

{translation}{}{Synthesis of polypeptide chains at the ribosome in response to information contained in mRNA molecules.}

{transverse [T] tubule}{}{Tubule that extends from the sarcolemma to a myofibril of striated muscles.}

{transverse plane}{}{A plane that divides the body into inferior and superior portions.}

{triad}{}{Two terminal cisternae and a T tubule between them.}

{trigeminal nerve}{}{Cranial nerve V; three-branched nerve that transmits sensory impulses from the face and jaw, and motor impulses to the muscles of mastication and the floor of the mouth.}

{triglyceride}{}{Lipid composed of three fatty acids combined with a glycerol molecule.}

{trochlear nerve}{}{Cranial nerve IV, to the muscle [superior oblique] turning around a pulley.}

{tropomyosin}{}{Fibrous protein found as a component of the actin myofilament.}

{troponin}{}{Globular protein component of the actin myofilament.}

{tumor}{}{Any swelling or growth; a neoplasm.}