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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.
C, E: male development. B, D, F: female development. Until about the ninth week of gestational age, [3] the sex organs of males and females look the same, and follow a common development. This includes the development of a genital tubercle and a membrane dorsally to it, covering the developing urogenital opening, and the development of ...
The metanephros develops from the ureteric bud, which is an outgrowth on the caudal part of the nephric duct, [170] [171] and the metanephrogenic blastema, which is part of the intermediate mesoderm surrounding the ureteral bud. [172] [173] The development of metanephros begins with the induction of a metanephrogenic blastema by the ureteric bud.
Metanephros is the most complex form of kidney. [44] Each metanephric kidney is characterized by a large number of nephrons and a highly branched system of collecting tubules and ducts, [28] that open into the ureter. [48] Such branching in the metanephros is unique in relation to the pronephros and mesonephros. [44]
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.
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 metanephrogenic blastema or metanephric blastema (or metanephric mesenchyme, or metanephric mesoderm) is one of the two embryological structures that give rise to the kidney, the other being the ureteric bud.
As development proceeds, the intermediate mesoderm differentiates sequentially along the anterior-posterior axis into three successive stages of the early mammalian and avian urogenital system, named pronephros, mesonephros and metanephros respectively (anamniote embryos form only a pronephros and mesonephros). [2]