Differentiation of the urogenital
sinus:
1-From the mesonephric duct (Wolff) arise:
Epididymis, Deferent duct, Seminal vesicle and Ejaculatory duct.
2-From the endoderm of the urogenital sinus
arise: Urinary bladder.
3-Out of the pelvic part of the definitive
urogenital sinus: the prostatic and membranous parts of the urethra, the
prostate and the bulbourethral gland (Cowper's).
4-Out of the phallic part of the definitive
urogenital sinus: the spongy part of the urethra and the urethral glands
(Littre's)
In females: Differentiation of the canal system in the genital organ:
*During the 7th week the canal system of the
female sex organs differentiates. The mesonephric duct and its tubules atrophy
and out of the paramesonephric duct (Müller) arises the future fallopian tube,
the uterus and the upper part of the vagina. Out of the upper, non-fused
portion of the paramesonephric duct (Müller) arises the fallopian tube and its
ampulla. The lower section fuses after it crosses medially on both sides of the
inferior ovarian gubernaculum and forms the utero-vaginal canal. The medial
septum in between disappears at the end of the 3rd month.
*Through canalization of the vaginal plate the
utero-vaginal canal opens itself towards the outside. The upper 3/4 of the
vagina comes from the mesoderm and the lower fourth from the endoderm.
*The fibromuscular walling forms from the
neighboring mesenchyma.