# Anatomy and Physiology of Animals/Glossary/T,U,V,W,X,Y,Z

A-B | C-D | E-F | G-H | I-J | K-L | M-N | O-P | Q,R,S | T,U,V,W,X,Y,Z | Print version
| Word | Meaning |
| T | |
| Target cell | A cell whose activity is affected by a particular hormone |
| Tarsals | The bones of the “ankle” |
| Tendons | A tough cord of fibrous connective tissue that connects muscles to bones |
| Testis | The male gonad that produces sperm |
| Testosterone | The hormone produced by the cells between the seminiferous tubules of the testis |
| Thoracic cavity | The chest cavity that contains the heart and lungs |
| Thorax | The part of the body between the neck and the diaphragm |
| Thymus gland | The organ dorsal to the sternum that is essential to the immune response |
| Thyroid gland | The endocrine gland with lobes on either side of the trachea |
| Thyroxine | The hormone secreted by the thyroid gland |
| Tibia | The medial bone of the lower hind limb |
| Tidal breathing | Normal at rest breathing |
| Tidal volume | The volume of air breathed in or out in any one “at rest” breath |
| Tissue | A group of similar cells |
| Tissue fluid | Plasma that has left the capillaries and flowed into the spaces between the cells of the tissues; also known as intercellular fluid or interstitial fluid |
| Total lung capacity | The sum of the tidal volume, inspiratory reserve, expiratory reserve and residual volume of the lungs |
| Trachea | The windpipe |
| Transverse | A crosswise slice of an animal or organ |
| Triceps | The muscle that extends from the shoulder to the elbow responsible for extending the forearm |
| Triglycerides | A biological compound consisting of three fatty acids linked to one glycerol molecule. A fat |
| Trunk | The part of the body to which the fore and hind limbs are attached |
| Tympanic membrane | The thin transparent membrane of connective tissue between the external ear, canal and the middle ear. Also called the eardrum |
| U | |
| Ulna | The longer bone of the forelimb between the humerus and the “wrist” |
| Umbilical cord | The cord containing arteries and vein that attaches the foetus to the placenta |
| Unguligrade locomotion | Locomotion on the “fingernails” as in horses and pigs |
| Urea | The soluble excretory product produced when excess amino acids (from proteins) are broken down by the body |
| Ureter | One of two tubes that connect the kidney with the bladder |
| Urethra | The duct from the bladder to the exterior of the body |
| Uric acid | An insoluble excretory product produced when excess amino acids(from proteins) are broken down by the body |
| Urinalysis | The analysis of urine |
| Urine | The fluid produced by the kidneys |
| Uterus | The hollow muscular organ in females where the foetus develops |
| V | |
| Vagina | The muscular, tubular organ in the female where sperm are deposited during copulation |
| Vagus nerve | The cranial nerve that controls the muscles that bring about swallowing,the muscles of the heart, airways, lungs, stomach and intestines |
| Vane | The flat part of a feather emerging from the shaft; there are two vanes per feather |
| Vas deferens | The duct that conducts the sperm from the epididymis to the urethra |
| Vascular | To do with blood |
| Vasoconstriction | The decrease in size of the channel down a blood vessel |
| Vaso dilation | The increase in size of the channel down a blood vessel |
| Vein | A blood vessel that carries blood towards the heart |
| Velvet | The tissue layer that covers antlers |
| Vena cava | One of two large blood vessels that return blood to the heart |
| Ventral | Nearer the belly of the animal than |
| Ventricles | The caudal chambers of the heart |
| Venule | A small vein |
| Vertebral canal | The channel that encloses and protects the spinal cord |
| Vertebrates | Animals that have a backbone or vertebral column |
| Vesicles | Small, intracellular membrane-bound sac |
| Vestibular organ | The organ of balance – semicircular canals and otolith organ |
| Villus (pl. villi) | A projection from the lining of the small intestine to help absorb digested food molecules |
| Viscera | The organs in the abdominal and pelvic cavities |
| Visceral skeleton | Bones formed in the organs of the body |
| Viscosity | The thickness or stickiness of a liquid |
| Vital capacity | The sum of the inspiratory and expiratory reserve volumes and the tidal volume |
| Vital capacity | The volume of the air expired when a maximum expiration follows a maximum inspiration |
| Vitamin | An organic molecule necessary in minute quantities for the proper functioning of the chemical processes in the body |
| Vitreous Humor | The fluid in the posterior chamber of the eye |
| W | |
| White matter | Masses of myelinated axons located in the brain and spinal cord |
| X | |
| Xiphoid process (or xiphisternum) | A small process/ extension at the lower part of the sternum. Cartilage at birth; gradually ossifies to bone and fuses with the sternum |
| Y | |
| Yellow marrow | Bone marrow that is yellow with fat; found at the ends of long bones |
| Z | |
| Zona pellucida | The tough layer surrounding the ovum |
| Zygote | Single cell resulting from the union of the sperm and egg |