Gonads: Lecture 13 - Reproductive Systems PDF

Gonadal primordia conversion ============================ Male and Female duct systems ============================ - Once testosterone is present then the **Wolfian** duct system differentiates into male duct system. - If testosterone is absent then the **Mullerian** duct system diff...

Gonadal primordia conversion ============================ Male and Female duct systems ============================ - Once testosterone is present then the **Wolfian** duct system differentiates into male duct system. - If testosterone is absent then the **Mullerian** duct system differentiates into female duct system. Female reproductive system ========================== Ovum maturation =============== Ovarian Cycle ============= Uterine Cycle ============= Uterine Cycle ============= - 1-menstruation: breakdown of the endometrium and release of blood. - 2-proliferative: formation of a new endometrium under the effect of estrogen - 3-secretory: under the effect of progesterone The Zygote ========== - A successful fertilization is the one that takes place in the oviduct. - A successful implantation is the one that takes place in the uterus. - Upon arrival to the uterus, the zygote embeds itself in the endomertium wall No zygote no pregnancy ====================== Twins ----- - Usually one ovum is released every month from alternating ovaries. - However sometimes two ova are released at the same time, and if they are both fertilized we get dizygotic fraternal twins. - In some cases, an ovum which is fertilized by one sperm and upon reaching a totipotent stage may have a cell detaching from it and is capable of forming an identical human being then we get monozgotic twins. Male reproductive system ======================== Testes ====== - The reproductive organ in males are the testes. - The testes is divided into two main structures: - The interstitial cells of leydig, where testosterone production takes place - The seminiferous tubules, where spermatogenesis takes place