|
A genital tubercle or phallic tubercle is a body of tissue present in the development of the reproductive system. It forms in the ventral, caudal region of mammalian embryos of both sexes, and eventually develops into a primordial phallus. In the human fetus, the genital tubercle develops around week 4 of gestation, and by week 9 becomes recognizably either a clitoris or penis. This should not be confused with the sinus tubercle which is a proliferation of endoderm induced by paramesonephic ducts. Even after the phallus is developed, the term genital tubercle remains, but only as the terminal end of it,〔(The University of North Carolina at Chapel Hill - Embryo images nr 024 )〕 which develops into either the glans penis or the glans clitoridis. The genital tubercle is sensitive to dihydrotestosterone and rich in 5-alpha-reductase, so that the amount of fetal testosterone present after the second month is a major determinant of phallus size at birth. ==See also== *Sexual differentiation 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Genital tubercle」の詳細全文を読む スポンサード リンク
|