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Female Reproduction. Oogenesis. http://www.youtube.com/watch?v=VPezOuOnq1g&feature=relmfu Begins with oogonia (ovary-specific stem cells) which multiply by mitosis and begin meiosis up to prophase I. It is then called a primary oocyte which remain dormant in a female’s ovaries until puberty.
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Oogenesis http://www.youtube.com/watch?v=VPezOuOnq1g&feature=relmfu • Begins with oogonia (ovary-specific stem cells) which multiply by mitosis and begin meiosis up to prophase I. • It is then called a primary oocyte which remain dormant in a female’s ovaries until puberty. • Follicle Stimulating Hormones (FSH) periodically stimulate follicles to grow and induce the primary oocytes to complete meiosis I and start meiosis II, but stops again at metaphase II. • Now called the secondary oocyte, the cell is released at ovulation when the follicle breaks open. • Meiosis does not continue until a sperm fertilizes the secondary oocyte and creates the ovum and oogenesis is then completed. • Unequal cytokinesis creates the secondary oocyte, but also a smaller polar body, which later disentegrates.
Oogenesis and Ovarian cycle GerminalEpithelium Secondary oocyte
Testosterone • A type of androgen: Steroid hormones produced by testes (hormones secreted by the anterior pituitary and hypothalamus control the secretion of androgen and sperm production) • Has three main roles: • Directly responsible for the primary sex characteristics. These characteristics are associated with the reproductive system essentially meaning the development of the vasadeferentia and other ducts, development of external reproductive structures, and sperm production. • Directly responsible for the secondary sex characteristics. These are features not directly related to reproduction meaning the deepening of the voice, distribution of facial and pubic hair, and muscle growth(androgens stimulate protein growth). • It also is a determinant of behavior in mammals and other vertebrates, specifically sexual behavior and sex drive; androgens also increase general aggression (in birds and frogs they promote singing and calling).