pronephros

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pronephros

 [pro-nef´ros] (Gr.)
the primordial kidney; an excretory structure or its rudiments developing in the embryo before the mesonephros; its duct is later used by the mesonephros, which arises caudal to it.

pro·neph·ros

, pl.

pro·neph·roi

(prō-nef'ros, -roy),
1. The definitive excretory organ of primitive fishes. Synonym(s): head kidney
2. In the embryos of higher vertebrates, a vestigial structure consisting of a series of tortuous tubules emptying into the cloaca by way of the primary nephric duct; in the human embryo, the pronephros is a very rudimentary and temporary structure, followed by the mesonephros and still later by the metanephros.
[pro- + G. nephros, kidney]

pronephros

/pro·neph·ros/ (pro-nef´ros) pl. proneph´roi  
1. a vestigial excretory structure developing in the embryo before the mesonephros; its duct is later used by the mesonephros, which arises caudal to it.
2. the definitive excretory organ of primitive fishes.proneph´ric

pronephros

(prō-nĕf′rəs, -rŏs′)
n. pl. proneph·roi (-roi) or proneph·ra (-rə)
A kidneylike organ, being either part of the most anterior pair of three pairs of organs in a vertebrate embryo, disappearing early in the embryonic development of most vertebrates.

pro·neph′ric (-rĭk) adj.

pronephros

[-nef′rəs] pl. pronephroi
Etymology: Gk, pro + nephros, kidney
the earliest and simplest kind of excretory organ in the developing vertebrate embryo. In humans and other mammals the structure is nonfunctional. Also called archinephron, head kidney, pronephron (pl. pronephra). See also mesonephros, metanephros. pronephric, adj.

pro·neph·ros

, pl. pronephroi (prō-nef'rŏs, -roy)
1. The definitive excretory organ of primitive fishes.
2. In the embryos of higher vertebrates, a vestigial structure consisting of a series of tortuous tubules emptying into the cloaca by way of the primordial nephric duct; in the human embryo, the pronephros is a very rudimentary, nonfunctional, and temporary structure, followed by the mesonephros and still later by the metanephros.
[pro- + G. nephros, kidney]

pronephros

the first excretory organ in the vertebrate embryo. Its duct (MULLERIAN DUCT) gives rise to the OVIDUCT in the female and degenerates in the male.

pronephros

pl. pronephroi [Gr.] the primordial kidney; nonfunctional in mammals; functional only in amphioxuses and lampreys; an excretory structure or its rudiments developing in the embryo before the mesonephros; its duct is later used by the mesonephros, which arises caudal to it.