The definitions used in this glossary of terminology either have been provided by the authors of the articles, or have been extracted wholly or in part, or paraphrased from the following sources: The American Medical Association Encyclopedia of Medicine, Charles B. Clayman, MD, Medical Editor, Random House, New York, 1989; Biotechnology from A to Z, 2d Edition, William Bains, Oxford University Press, New York, New York, 2002; A Dictionary of Genetics, 6th Edition, Robert C. King and William D. Stansfield, Oxford University Press, New York, New York, 2002; Dorland's Illustrated Medical Dictionary, 29th and 30th Editions, W. B. Saunders Company, Philadelphia, 2000, 2003; Genes VII, Benjamin Lewin, Oxford University Press, New York, New York, 2000; The Gale Encyclopedia of Genetic Disorders, Volumes I and II, Stacey L. Blachford, Ed., Thomson Learning, New York, New York, 2002; The Merriam-Webster Dictionary, Merriam-Webster, Inc., Springfield, Massachusetts, 1997; Molecular Biology of the Cell, 3rd Edition, Bruce Alberts, et al., Garland Publishing, 1994; The Random House Dictionary of the English Language, Unabridged Edition, 1966; Webster's Ninth New Collegiate Dictionary, 1991.

DEFINITION:

urinary tract

The organs and passageways that participate in the excretion of the urine from the kidneys through the bladder and the urinary meatus.

The urinary tract consists of the kidneys (with their blood and nerve supplies), the renal pelves (funnel-shaped ducts that channel urine from the kidneys into the ureters), the ureters, bladder, and urethra.

The kidneys make urine by filtering blood. The urine collects in the renal pelves and then passes down the ureters into the bladder by gravity and by peristalsis (wavelike contractions of the ureteric walls). Urine is then stored in the bladder until a sufficient amount is present to stimulate micturition (passage of urine). When the bladder contracts, the urine is expelled from the body via the urethra.