mesonephros


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Related to mesonephros: metanephros, mesonephric duct

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.
[meso- + G. nephros, kidney]

mesonephros

/meso·neph·ros/ (-nef´ros) pl. mesoneph´roi   [Gr.] the excretory organ of the embryo, arising caudad to the pronephric rudiments or the pronephros and using its ducts.

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.

mes′o·neph′ric adj.

mesonephros

[-nef′rəs] pl. mesonephra, mesonephroi
Etymology: Gk, mesos + nephros, kidney
the second type of excretory organ to develop in the vertebrate embryo. It consists of a series of twisting tubules that arise from the nephrogenic cord caudal to the pronephros and that at one end form the glomerulus and at the other connect with the excretory mesonephric duct. The organ is the permanent kidney in lower animals, but in humans and various other mammals it is functional only during early embryonic development and is later replaced by the metanephros, although the duct system is retained and incorporated into the male reproductive system. Also called mesonephron, middle kidney, wolffian body. See also metanephros, pronephros. mesonephric, mesonephroid, 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]

mesonephros

(mez´ənef´rəs),
n the second type of excretory organ to develop in the vertebrate embryo. The organ is the permanent kidney in lower animals, but in humans and various other mammals it is functional only during early embryonic development.

mesonephros

pl. mesonephroi [Gr.] the excretory organ of the embryo, arising caudal to the pronephros and using its duct. Displaced by the metanephros which becomes the kidney of the postnatal animal.
References in periodicals archive ?
The results showed that the proximal luminal diameter increased in the mesonephros of all the experimental groups than the control group.
These cells move toward the dorsal and the dorsal mesentery and then go to mesonephros where gonad formed and in continuo, first gonadal growth was mentioned as swollen in the ventromedial part of mesonephros.
The genital ridge is located superficial to and medial to the developing mesonephros.
5 fetal testis was removed with the adjacent mesonephros, placed on a filter floating in a culture dish on 0.
Mesonephros The early embryonic kidney that eventually regresses as the metanephric kidneys develop.
At approximately 8 weeks of fetal gestation, the testis forms from the urogenital ridge by the condensation of a longitudinal cell mass opposite the middle third of the mesonephros.
The authors suggest the explanation for this varying pattern based on this step of the embryological development of the right renal vein: There was an error on the fusion of the branches to the dorsal mesonephros derived from the right postcardinal vein, the dorsal-medial branches of the right supracardinal vein and the ventral branches of the right subcardinal vein (the latter represented by the IRRV, marked by the presence of its gonadal tributary (Gillot).
The close relationship between the mullerian ducts, which fuse to form the uterus, and the mesonephros during embryologic life supports this proposed origin.
In an 18 mm fetus, the developing mesonephros, metanephros, suprarenal glands and gonads are supplied by nine pairs of lateral mesonephric arteries arising from the dorsal aorta.
Ovaries could be distinguished from testes because they are thinner and more closely associated with mesonephros, and a fine blood vessel was detectable on the testes at this fetal stage.