Search results
Results from the WOW.Com Content Network
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.
Pronephros is the most basic of the three excretory organs that develop in vertebrates, corresponding to the first stage of kidney development. It is succeeded by the mesonephros, which in fish and amphibians remains as the adult kidney. In amniotes, the mesonephros is the embryonic kidney and a more complex metanephros acts as the adult kidney ...
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 ...
According to the complexity of the organisation of the nephron, the kidneys are divided into pronephros, mesonephros and metanephros. [17] The nephron by itself is similar to pronephros as a whole organ. [18] The simplest nephrons are found in the pronephros, which is the final functional organ in primitive fish. [19]
Kidney development, also called nephrogenesis, proceeds through a series of three successive developmental phases: the pronephros, mesonephros, and metanephros. The metanephros are primordia of the permanent kidney.
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.
The permanent organs of the adult are preceded by a set of structures which are purely embryonic, and which with the exception of the ducts disappear almost entirely before birth. These embryonic structures are on either side; the pronephros, the mesonephros and the metanephros of the kidney, and the Wolffian and Müllerian ducts of the sex organ.
The nephrogenic cords are located on the posterior wall of the embryo, which is where the kidneys are located. The nephrogenic cords go through three phases of development which overlap to some extent, both in space and in time. The 1st phase is the pronephros, the 2nd phase is the mesonephros and the 3rd and final stage is the metanephros.