Dictionary

Body systems

Anatomy and the conditions of each body system, from the heart and lungs to the skin.

vesicoureteral refluxThe backward flow of urine from the bladder up into the ureters and toward the kidneys.

villusOne of the tiny, finger-like folds that line the small intestine and take in nutrients.

viral gastroenteritisAn infection of the stomach and intestines caused by a virus, such as norovirus or rotavirus.

viral infectionAn illness caused by a virus, a very small germ that can multiply only inside living cells.

Virchow triadThree conditions that together promote blood clots in vessels: slowed blood flow, damage to the vessel wall, and blood that clots too easily.

visceralHaving to do with the internal organs, especially those in the chest and belly.

visual acuityHow clearly and sharply a person can see.

vitamin AA fat-soluble vitamin needed for vision, especially in dim light, healthy skin and a working immune system.

vitamin B12A vitamin from animal foods that the body needs to make red blood cells and keep nerves healthy; also called cobalamin.

vitamin CA water-soluble vitamin in fruits and vegetables that the body needs to make collagen, heal wounds and absorb iron; also called ascorbic acid.

vitamin DA fat-soluble vitamin that the skin makes in sunlight and that helps the body absorb calcium for strong bones.

vitiligoA long-term skin condition in which patches of skin lose their color.

voidingPassing urine; emptying the bladder.

voluntary muscleMuscle that a person can move by choice, such as the muscles of the arms and legs.

vomitingForcefully bringing up the contents of the stomach through the mouth.

wartA small, rough, harmless growth on the skin caused by a human papillomavirus (HPV) infection.

weltA raised, red or pale, often itchy area on the skin; also called a wheal.

WernickeThe name of a German neurologist, used in Wernicke encephalopathy (from low thiamine) and Wernicke aphasia (trouble understanding language).

Wernicke encephalopathyA sudden, serious brain disorder that results from a severe lack of thiamine (vitamin B1).

whealA raised, red or pale, itchy bump on the skin that comes and goes; a single hive.

wheezingA high-pitched, whistling sound made as air moves through narrowed airways.

white blood cellA blood cell that is part of the immune system and helps the body fight infection and other foreign material.

whole grainA grain that still has all three parts of the kernel, the bran, germ and endosperm.

Wilms tumorA cancer of the kidney that develops in young children.

withdrawalThe physical and mental symptoms that occur when a person stops or cuts down a substance the body has come to depend on.

woundA break or injury in the skin or the tissue under it.

wound healingThe body's process of repairing damaged skin and tissue.

wrinkleA crease or fold, either in the skin or in fabric such as bed sheets.

xiphoid processThe small, pointed tip at the lower end of the breastbone.

yeast infectionAn infection with Candida, a yeast that normally lives on the body in small numbers.

Zollinger-Ellison syndromeA rare condition in which tumors that release the hormone gastrin make the stomach produce far too much acid.

zygoteThe single cell formed when a sperm joins an egg at fertilization.