PHS 3341 Lecture 19: Reproduction 2
7 Dec 2016
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Ovaries (2) - attached by a pair of ligaments to the uterus. Ovaries contain 2 to 4 million oocytes at birth. Of the ~400000 that remain at puberty, ~400 will be ovulated. Arrested at prophase of meiosis i; resumed at ovulation (puberty); second meiotic division after fertilization; process ceases after menopause. Only primary oocytes remain at birth; each primary oocyte gives rise to one ovum; other daughter cells (polar body) degenerate. Each primary spermatocyte gives rise to 4 spermatids that all become spermatozoa. Cytoplasmic oocyte receives most of cytoplasm is divided equally between. Oocyte receives most of the cytoplasm; polar bodies get chromosomes, but almost no cytoplasm. Cytoplasm is divided equally between daughter cells; almost all cytoplasm shed during spermiogenesis. Cumulus granulosa cells - get ovulated with oocyte. Diagram of a secondary (antral or graafian) follicle. Primordial germ cells each become surrounded by one layer of granulosa cells. Occurs in response to the lh surge (about 36 hours later)
