Female Reproductive System - Physiology and Anatomy - Lecture Slides, Slides of Physiology

Download Female Reproductive System - Physiology and Anatomy - Lecture Slides and more Slides Physiology in PDF only on Docsity! Female Reproductive System 20-46 Docsity.com Female Reproductive System • Ovaries contain large number of follicles that produce female gametes (eggs or ova) in ovarian cycle • Extensions of fallopian tubes called fimbriae partially cover each ovary – The cilia of its lining draw in ovulated eggs 20-47 Fig 20.24 Docsity.com Production of Oocytes • Germ cells that migrate into ovaries from yolk sac multiply so that at 5 mo. gestation, ovaries contain 6-7 million oogonia – Production of oogonia then ceases forever • Toward end of gestation, oogonia (now 1o oocytes) begin meiosis but arrest in prophase I • There is a continual loss of 1o oocytes throughout life – At birth are 2 million left – At puberty 400,000 are left • 400 oocytes are ovulated during reproductive years; rest undergo apoptosis 20-50 Docsity.com Ovarian Cycle • 1o oocytes are contained in 1o follicles – Consisting of oocyte + follicle cells • In response to FSH some follicles enter ovarian cycle & grow, producing layers of granulosa cells • Some 1o follicles continue, developing vesicles & becoming 2o follicles 20-51 Docsity.com Ovarian Cycle continued • One follicle continues growth – Vesicles fuse, forming fluid-filled cavity called an antrum • Is now called a Graafian follicle 20-52 Docsity.com Ovulation • By 10-14 days after menstruation begins, only 1 follicle survives – Others become atretic follicles (degenerate) • Surviving graafian follicle forms bulge on surface of ovary – Secretes increasing levels of E 20-55 Docsity.com Ovulation continued • Graafian follicle releases egg into Fallopian tube at ovulation 20-56 Docsity.com Ovulation continued • If fertilized, egg completes meiosis II with formation of another polar body • Egg degenerates in 2 days if not fertilized 20-57 Docsity.com