pronephros

pronephros

[proh-nef-ros, -ruhs]
noun, plural pronephroi [proh-nef-roi] , pronephra [proh-nef-ruh] . Embryology.
one of the three embryonic excretory organs of vertebrates, which becomes the functional kidney of certain primitive fishes.


Origin:
1875–80; < Neo-Latin < Greek pro- pro-2 + nephrós kidney

pronephric [proh-nef-rik] , adjective
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World English Dictionary
pronephros (prəʊˈnɛfrɒs)
 
n , pl -roi, -ra
mesonephros See also metanephros the first-formed anterior part of the embryonic kidney in vertebrates, which remains functional in the larvae of the lower vertebrates
 
[C19: New Latin, from pro-² + Greek nephros kidney]
 
pro'nephric
 
adj

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American Heritage
Medical Dictionary

pronephros pro·neph·ros (prō-něf'rəs, -rŏs')
n. pl. pro·neph·roi (-roi) or pro·neph·ra (-rə)
A kidneylike organ, being either part of the most anterior pair of three pairs of organs in a vertebrate embryo, usually disappearing early in embryonic development.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Encyclopedia Britannica
Encyclopedia

pronephros

most primitive of the three vertebrate kidneys, active in the adults of some primitive fish (lampreys and hagfish), the embryos of more advanced fish, and the larvae of amphibians. It is a paired organ consisting of a series of nephrons that filter urine from both the pericardial cavity fluids via openings called nephrostomes and the bloodstream from the glomerulus. Cells of the nephron tubule may secrete nitrogenous wastes into the urine and reabsorb water and nutrients. Urine passes from the nephrons into one of two long tubes, the Wolffian ducts, which run along either side of the body cavity and empty into a bladderlike urogenital sinus.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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