RENAL SYSTEM

in humans, organ system that includes the kidneys, where urine is produced, and the ureters, bladder, and urethra for the passage, storage, and voiding of urine. In many respects the human excretory, or urinary, system resembles those of other mammalian species, but it has its own unique structural and functional characteristics. The terms excretory and urinary emphasize the eliminatory function of the system. The kidneys, however, both secrete and actively retain within the body certain substances that are as critical to survival as those that are eliminated. The system contains two kidneys, which control the electrolyte composition of the blood and eliminate dissolved waste products and excess amounts of other substances from the blood; the latter substances are excreted in the urine, which passes from the kidneys to the bladder by way of two thin muscular tubes called the ureters. The bladder is a sac that holds the urine until it is eliminated through the urethra. Additional reading Renal system Don W. Fawcett, A Textbook of Histology, 11th ed. (1986), an illustrated text on histology and fine structure; D.J. Cunningham, Cunningham's Textbook of Anatomy, 12th ed., edited by G.J. Romanes (1981), a traditional text on human anatomy; Henry Gray, Anatomy of the Human Body, 30th American ed., edited by Carmine D. Clemente (1985), a treatise frequently revised over the past century and still regarded as one of the great anatomical texts; Arthur W. Ham, Ham's Histology, 9th ed. (1987), a text paying particular attention to the correlation of structure and function; and W.J. Hamilton and H.W. Mossman, Human Embryology: Prenatal Development of Form and Function, 4th ed. (1972), one of the leading textbooks on human embryology. D. Bulmer, Functional Anatomy of the Urogenital System (1974); and John A. Gosling, John S. Dixon, and John R. Humpherson, Functional Anatomy of the Urinary Tract (1982), are specialized texts. Human excretion The following works provide detailed and well-written surveys of the field of kidney function in a form suitable for medical students and for others with a good scientific grounding: E.J. Moran Campbell et al. (eds.), Clinical Physiology, 5th ed. (1984); and J.M. Forrester et al. (eds.), A Companion to Medical Studies: Anatomy, Biochemistry, and Physiology, 3rd ed. (1985).