Glossary - Definitions

V

vacuole (vak-yoo´=ol) A small space or cavity within the cytoplasm of a cell.

vagina (vua-ji´nua) A tubular organ leading from the uterus to the vestibule of the female reproductive tract that receives the male penis during coitus.

vallate papillae (val´=at pua-pil´e) The largest papillae on the surface of the tongue. They are arranged in an inverted V-shaped pattern at the posterior portion of the tongue.

vasectomy (vua-sek´tuo-me, va-zek´tuo-me) Surgical removal of portions of the ductus deferentia to induce infertility.

vasoconstriction (va´´zo-kon-strik´shun) Narrowing of the lumen of blood vessels due to contraction of the smooth muscles in their walls.

vasodilation (va´´zo-di-la´shun) Widening of the lumen of blood vessels due to relaxation of the smooth muscles in their walls.

vasomotor center (va´´zo-mo´tor) A cluster of nerve cell bodies in the medulla oblongata that controls the diameter of blood vessels. It is therefore important in regulating blood pressure.

vein (v=an) A blood vessel that conveys blood toward the heart.

vena cava (ve´nau ka´vua) One of two large vessels that return deoxygenated blood to the right atrium of the heart.

ventilation (ven´´tu1-la´shun) Breathing; the process of moving air into and out of the lungs.

ventral (ven´tral) Toward the front or facing surface; the opposite of dorsal; also called inferior.

ventricle (ven´tru1-k'l) A cavity within an organ; especially those cavities in the brain that contain cerebrospinal fluid and those in the heart that contain blood to be pumped from the heart.

venule (ven´yool) A small vessel that carries venous blood from capillaries to a vein.

vermis (ver´mis) The coiled middle lobular structure that separates the two cerebellar hemispheres.

vertebral canal (ver´tue-bral) The tubelike cavity extending through the vertebral column that contains the spinal cord; also called the spinal canal.

vertigo (ver´tu1-go) A feeling of movement or loss of equilibrium.

vestibular window See oval window.

vestibule (ves´tu1-byool) A space or cavity at the entrance to a canal, especially that of the nose, inner ear, or vagina.

villus (vil´us) A minute projection that extends outward into the lumen from the mucosal layer of the small intestine.

virulent (vir´yuu-lent) Pathogenic; able to cause disease.

viscera (vis´er-a) The organs within the abdominal or thoracic cavities.

visceral (vis´er-al) Pertaining to the membranous covering of the viscera.

visceral peritoneum (per´´u1-tuo-ne´um) A serous membrane that covers the surfaces of abdominal viscera.

visceral pleura (ploor´ua) A serous membrane that covers the surfaces of the lungs.

visceroceptor (vis´´er-uo-sep´tor) A sensory receptor located within body organs that responds to information concerning the internal environment.

vitreous humor (vit´re-us hyoo´mer) The transparent gel that occupies the space between the lens and retina of the eyeball.

Volkmann's canal (f=olk´manz) See perforating canal.

vulva (vul´vua) The external genitalia of the female that surround the opening of the vagina.

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