FATE OF THE MESONEPHRIC DUCTS

By the end of the exstrophy process, the mesonephric ducts terminate in the bladder medial and inferior to the future ureteric orifices. Although it was previously thought that the mesonephric ducts contributed to the formation of the trigone, this long-held view has recently been called into doubt.

In males, the mesonephric ducts become the ejaculatory ducts, vas deferens, seminal glands (vesicles), and epididymis. In females, in contrast, the mesonephric ducts largely degenerate, giving rise only to the vestigial structures known as the epoöphoron and paroöphoron. Instead, the paramesonephric (müllerian) ducts, which degenerate in males, are responsible for formation of the female reproductive tract. These ducts appear lateral to the mesonephric ducts during the sixth week, and in females they become the uterine (fallopian) tubes, uterus, and upper two thirds of the vagina.