BIOC19H3 Chapter Notes -Oogenesis, Germ Cell, Meiosis
Document Summary
Spermatogenesis: four haploid sperm cells each able to potentially fertilize an egg, produced by meiosis from each diploid stem cell triggered into sperm cell differentiation. Oogenesis: one large haploid egg (receiving bulk of cytoplasm) and 3 small haploid polar bodies, produced by meiosis from each diploid stem cell triggered into oogenesis. Interrelated ovary functions: oogenesis production of haploid female gametes, production of steroid hormone estrogen and progesterone. Steroid hormones estrogen and progesterone: estrogen promotes growth and maturation of internal and external sex organs. Responsible for female characteristics that develop at puberty: progesterone prepares uterus for pregnancy. Maintains pregnancy decrease mother"s immune response to enable gestation, decreases contractibility of uterus muscle, inhibits lactation. Drop in progesterone during pregnancy may be involved in inducing labor. Primordial follicles are quiescent for yeast until puberty, then recruited monthly to undergo growth process: ovarian follicle provides microenvironment" for developing oocyte. Initial recruitment primordial follicles induced to develop, thought to involve growth factors.
