Human Reproduction

Cleavage in the fertilized egg in humans starts in the fallopian tube (oviduct) during the conduction of zygote towards uterus.

or thyroid stimulating hormone has no role in menstruation.

The formation and maturation of male gametes or spermatozoon is called spermatogenesis. Sperms are produced in the seminiferous tubules oftestes. Diploid spermatogonia present beneath 3 to 5 cells deep from outermost layer of seminiferous tubules, increase their number by ordinary mitotic divisions and each becomes a primary spermatogonial cell or primary spermatocyte. Each primary spermatocyte undergoes first meiotic (reductional) division and forms two secondary spermatocytes. Each of these, without any intervention undergoes the second meiotic division and gives rise to two spermatids. Each spermatid undergoes the process of spermiogenesis to become a sperm.