Search results
Results from the WOW.Com Content Network
The mesonephros persists and forms the anterior portion of the permanent kidneys in fish and amphibians, but in reptiles, birds, and mammals, it atrophies and for the most part disappears rapidly as the permanent kidney (metanephros) begins to develop [2] during the sixth or seventh week. By the beginning of the fifth month of human development ...
The development of the kidney proceeds through a series of successive phases, each marked by the development of a more advanced kidney: the archinephros, pronephros, mesonephros, and metanephros. [1] The pronephros is the most immature form of kidney, while the metanephros is most developed. The metanephros persists as the definitive adult kidney.
The mesonephric duct connects the primitive kidney, the mesonephros, to the cloaca. It also serves as the primordium for male urogenital structures including the epididymides, vasa deferentia, and seminal vesicles.
Mesonephros develops after the pronephros, replacing it. The mesonephros is the final kidney in amphibians and most fish. In more advanced vertebrates , mesonephros develops during embryogenesis and is then replaced by the metanephros. [36] In reptiles and marsupials, it remains functional for some time after birth along with the metanephros.
The mesonephros persists and form the permanent kidneys in fish and amphibians, but in reptiles, birds, and mammals, it atrophies and for the most part disappears rapidly as the permanent kidney (metanephros) develops beginning during the sixth or seventh week, so that by the beginning of the fifth month only the ducts and a few of the tubules ...
The aorta-gonad-mesonephros (AGM) region is an area derived from splanchnopleura mesoderm identified in embryonic humans, mice, and non-mammalian vertebrates such as birds and zebrafish. It contains the dorsal aorta, genital ridges and mesonephros and lies between the notochord and the somatic mesoderm, extending from the umbilicus to the ...
The mesonephros derives from intermediate mesoderm in the upper thoracic to upper lumbar segments. Excretory tubules are formed and enter the mesonephric duct , which ends in the cloaca . The mesonephric duct atrophies in females, but participate in development of the reproductive system in males.
Then, caudal to the pronephros, the mesonephros develops, which is the functioning kidney of the embryo. [166] [167] Subsequently, the mesonephros degrades in females, and in males it participates in the development of the reproductive system. The third stage is the formation of the metanephros in the caudal part of the embryo.