Development of the Reproductive System Quiz

See In the Female. Option B is correct. The embryo starts with two sets of internal ducts: the paramesonephric (Müllerian) ducts and the mesonephric (Wolffian) ducts. In the normal female, the paramesonephric ducts persist and develop into the uterus and the fallopian tubes, and they contribute to the upper vagina. Their lower portions fuse in the midline to form the uterus, and the unfused upper portions form the tubes. Incomplete fusion can lead to an abnormally shaped uterus. In a male, anti-Müllerian hormone (AMH), produced by Sertoli cells in the testes, blocks the development of the uterus and fallopian tubes from the Müllerian duct. Testosterone from Leydig cells, the hormone-producing cells between the tubules of the testis, instead maintains the Wolffian ducts, which form the male internal passages. In the female there is no AMH and no testosterone, so the Müllerian ducts develop and the Wolffian ducts regress. Memory aid: Müllerian ducts make the Mother's organs (uterus and tubes); Wolffian ducts make the male tubes.

• Female ducts: the paramesonephric ducts persist.
• Derivatives: the uterus, the fallopian tubes and the upper vagina.
• In males: AMH from Sertoli cells blocks their development.