mesonephros

mesonephros

 [mez″o-nef´ros] (pl. mesoneph´roi) (Gr.)

the excretory organ of the embryo, arising caudad to the pronephros and using its duct. adj., adj mesoneph´ric.

mes·o·neph·ros

, pl.

mes·o·neph·roi

(mez'ō-nef'ros, -roy),

One of three excretory organs appearing in the evolution of vertebrates; in life forms with a metanephros, the mesonephros is located between the regressing pronephros and the metanephros, cephalic to the latter. In young mammalian embryos, the mesonephros is well developed and briefly functional until establishment of the metanephros, the definitive kidney; in older embryos, the mesonephros undergoes regression as an excretory organ, but its duct system is retained in the male as the epididymis and ductus deferens.

Synonym(s): middle kidney, wolffian body

[meso- + G. nephros, kidney]

mesonephros

(mĕz′ə-nĕf′rəs, -rŏs′, mĕs′-)

n.

The second of the three excretory organs that develop in a vertebrate embryo, becoming the functioning kidney in fish and amphibians but replaced by the metanephros in birds, reptiles, and mammals. Also called Wolffian body.

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mes′o·neph′ric adj.

mesonephros

The second stage in renal development, which follows the pronephros and precedes the metanephros/adult kidney. The mesonephros appears after the first embryologic month as an oblong mass that co-develops with the embryonal gonads and disappears with maturation; vestigial mesonephric tissue (wolffian duct) remnants are present in adults as efferent ductules in the testis, and tubules of epiphoron in women.

mes·o·neph·ros

, pl. mesonephroi (mez'ō-nef'ros, -roy)

One of three excretory organs appearing in the evolution of vertebrates; in life forms with a metanephros, it is located between the regressing pronephros and the metanephros, cephalic to the latter. In young mammalian embryos, the mesonephros is well developed and briefly functional until establishment of the metanephros, the definitive kidney; in older embryos, the mesonephros undergoes regression as an excretory organ, but its duct system is retained in the male as the epididymis and ductus deferens.
Synonym(s): wolffian body.

[G. meso- middle + G. nephros, kidney]

mesonephros

or

Wolffian body

the middle part of the embryonic kidney which in fish and amphibia is the functional kidney, but which gives rise embryologically to the tubules of the testis in mammals, birds and reptiles. See also WOLFFIAN DUCT.

Wolff,

Kaspar F., German embryologist in Russia, 1733-1794.

wolffian body - one of three excretory organs appearing in the evolution of vertebrates. Synonym(s): canal of Oken; corpus of Oken; mesonephros

wolffian cyst - a cyst lying in the broad ligaments of the uterus and arising from any mesonephric structures.

wolffian duct - a duct in the embryo draining the mesonephric tubules. Synonym(s): mesonephric duct

wolffian rest - remnants of the wolffian duct in the female genital tract that give rise to cysts. Synonym(s): mesonephric rest

wolffian ridge - one of the paired longitudinal ridges developing in the dorsal body wall of the embryo. Synonym(s): urogenital ridge

wolffian tubules - Synonym(s): Kobelt tubules

mes·o·neph·ros

, pl. mesonephroi (mez'ō-nef'ros, -roy)

One of three excretory organs appearing in the evolution of vertebrates.
Synonym(s): wolffian body.

[G. meso- middle + G. nephros, kidney]