Mesonephros


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Related to Mesonephros: metanephros, mesonephric duct

mesonephros

[¦mez·ə′ne‚frōs]
(embryology)
One of the middle of three pairs of embryonic renal structures in vertebrates; persists in adult fish and is replaced by the metanephros in higher forms.

Mesonephros

 

wolffian body, a paired excretory organ in vertebrates.

The mesonephros consists of numerous twisting tubules that open at one end into the body cavity and at the other into the mesonephric (wolffian) duct. Each tubule has a lateral outgrowth —the malpighian corpuscle. In fish and amphibians, the mesonephros functions throughout life; in reptiles, birds, and mammals, including man, it functions only during the early stages of embryonic development, being subsequently replaced by the metanephros. At first the metanephros is metameric in structure, but this is lost as the organism grows. In the males of higher vertebrates, most of the mesonephros becomes an appendage of the testis and, with the wolffian duct, forms the vas deferens; in the females, the mesonephros is reduced.

References in periodicals archive ?
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.
Lemly (2002) reported that Belews lake green sunfish that had accumulated high levels of Se showed that numerous tubular casts were present, and tubular epithelium was desquamated, vacuolated, and often destroyed (which can render the tubular system of the mesonephros incapable of functioning properly).
5 fetal testis was removed with the adjacent mesonephros, placed on a filter floating in a culture dish on 0.
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 close relationship between the mullerian ducts, which fuse to form the uterus, and the mesonephros during embryologic life supports this proposed origin.