Nephron

nephron: see urinary system.

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nephron

Functional unit of the kidney that removes waste and excess substances from the blood to produce urine. Each of the million or so nephrons in each kidney is a tubule 1.2–2.2 in. (30–55 mm) long. At one end it is closed, expanded, and folded into a double-walled cuplike structure (Bowman's capsule) enclosing a cluster of capillaries (glomerulus). Fluid forced out of the blood through the capillary walls of the glomerulus into Bowman's capsule flows into the adjacent renal tubule, where water and nutrients are selectively reabsorbed from the fluid back into the blood, and electrolytes such as sodium and potassium are balanced in several distinct sections along its length. The final concentrated product is urine. See also urinary system.

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nephron [′nef‚rän]

(anatomy)

The functional unit of a kidney, consisting of the glomerulus with its capsule and attached uriniferous tubule.

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Nephron 

the basic structural and functional unit of the kidneys in vertebrate animals and man. A distinction is made between aglomerular and glomerular nephrons. Aglomerular nephrons are found in certain fishes and contain cells of a single type; glomerular nephrons, found in all other vertebrates and in man, contain the Malpighian bodies and Bowman’s capsules. The renal tubules extend from Bowman’s capsules.

The cells of glomerular nephrons are highly specialized to perform the functions required in the formation of urine—filtration, reabsorption, and secretion. In embryos the nephron also includes the nephrostomes, which are the ciliated infundibuli of the tubules. The nephrostomes open into the body cavity.