Development
The urinary and reproductive organs are developed from the intermediate mesoderm. The permanent organs of the adult are preceded by a set of structures that are purely embryonic, and that, with the exception of the ducts, disappear almost entirely before the end of fetal life. 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 pronephros disappears very early; the structural elements of the mesonephros mostly degenerate, but the gonad is developed in their place, with which the Wolffian duct remains as the duct in males, and the Müllerian as that of the female. Some of the tubules of the mesonephros form part of the permanent kidney.
Read more about this topic: Genitourinary System
Famous quotes containing the word development:
“I can see ... only one safe rule for the historian: that he should recognize in the development of human destinies the play of the contingent and the unforeseen.”
—H.A.L. (Herbert Albert Laurens)
“There are two things which cannot be attacked in front: ignorance and narrow-mindedness. They can only be shaken by the simple development of the contrary qualities. They will not bear discussion.”
—John Emerich Edward Dalberg, 1st Baron Acton (1834–1902)
“And then ... he flung open the door of my compartment, and ushered in “Ma young and lovely lady!” I muttered to myself with some bitterness. “And this is, of course, the opening scene of Vol. I. She is the Heroine. And I am one of those subordinate characters that only turn up when needed for the development of her destiny, and whose final appearance is outside the church, waiting to greet the Happy Pair!””
—Lewis Carroll [Charles Lutwidge Dodgson] (1832–1898)