Ulcer (uhl-ser): A lesion in which the tissue surface is eroded away; painful oral ulcers may be a symptom of calicivirus

Undercoat: The soft and dense down hairs of the undercoat are the shortest hairs, which insulate and help regulate body temperature, and. If not groomed properly, is prone to matting

Upper respiratory tract: The section of the respiratory system that contains the mouth, nose, pharynx, larynx, trachea, and epiglottis

Uremia (yoo-ree-mee-uh): The dangerous buildup in the bloodstream of toxins and waste products, such as urea and creatinine, which may occur with urethral obstruction

Uremic (yoo-ree-mik): A condition in which waste builds up in the bloodstream

Ureter (yoo-ree-ter): The tube leading from the kidney to the bladder

Urethra (yoo-ree-thre): The tube leading from the bladder to the outside

Urticaria (ur-ti-kair-ee-uh): Raised, itchy areas of skin, also known as hives, which is rare in cats but may indicate an allergic reaction to medications and insect bites and stings

Utricle (yoo-tri-kuhl): A sac inside the middle ear partly responsible for an animal’s sense of balance

Uvea (yoo-vee-uh): The part of the eyeball consisting of the iris, ciliary body and choroid

Uveitis (yoo-vee-ahy-tis): Painful inflammation of the structures of the uvea, located in the middle layer of the eye, which may lead to blindness ; the most common infectious diseases associated with uveitis are toxoplasmosis, feline infectious peritonitis and feline immunodeficiency virus


Valiance (va-lee-uhns): Refers to an animal’s response to novel stimuli; a high valiant kitten or cat is likely to approach new stimuli while one who is low valiant is likely to retreat

Vascular ring anomaly: A congenital condition which can lead to compression of the esophagus (megaesophagus) and cause food to be regurgitated

Vector (vek-ter): Any organism that carries an infectious agent between organisms of a different species, such as fleas that transmit feline bartonella and ticks that transmit Cytauxzoon

Vellus (veh-luhs): The sparse and baby-fine hair, known as peach fuzz, that covers the body of Sphynx cats and humans

Venipuncture (vee-nuh-puhngk-chur): The insertion of a needle into a vein to withdraw blood or give drugs, medications and fluids

Vermicide (vur-muh-sahyd): Anything that is designed to kill worms or other parasites; anthelmintic substance

Vermifuge (vur-muh-fyooj): Any chemical that causes worms or parasitic worms to be expelled from an animal’s body

Vertebrae (vur-tuh-brey): The bones of the spine, which, in cats, have elastic cushioning on the disks between the bones that contribute to their grace, flexibility and speed

Vibrassae (vai-bri-see): Hairs, also known as whiskers, located on the chin, above the eyes and lower back of the front legs, which have nerve-packed follicles and are 2-3 times thicker and 3 times deeper than body hairs

Visceral (vih-seh-rul): Related to the viscera, which are the soft internal organs of the body, including the lungs, heart and organs of the digestive, excretory, reproductive and circulatory systems

Vitreous (vi-tree-uhs): A clear, gel-like fluid in the space in the eye between the lens and retina, which may be affected by uveitis

Vomiting: The ejection of the contents from the stomach and upper intestine with active retching, as opposed to ejection of the contents from the esophagus and stomach without active retching