Organismal Development Part 4 Female Animals Female Reproductive

Organismal Development Part 4 Female Animals

Female Reproductive Anatomy Ovaries Oviduct Follicles Uterus Uterine wall Endometrium Cervix Vagina Corpus luteum

Oogenesis in the ovaries Ovary Primary germ cell in embryo Differentiation Oogonium in ovary Oogonium Mitotic division Primary oocyte within follicle Primary oocyte Completion of meiosis I and onset of meiosis II First polar body Growing follicle Secondary oocyte Ovulation Entry of sperm triggers completion of meiosis II Second polar body Mature follicle Ruptured follicle Ovum Ovulated secondary oocyte Corpus luteum Degenerating corpus luteum

Control by hypothalamus Inhibited by combination of estrogen and progesterone Hypothalamus Female Reproductive Cycle in Humans Stimulated by high levels of estrogen Gn. RH Anterior pituitary FSH Inhibited by low levels of estrogen LH Pituitary gonadotropins in blood LH FSH and LH stimulate follicle to grow LH surge triggers ovulation Ovarian cycle Growing follicle Corpus luteum Mature follicle Follicular phase Ovulation Degenerating corpus luteum Luteal phase Progesterone and estrogen secreted by corpus luteum Estrogen secreted by growing follicle in increasing amounts Ovarian hormones in blood Peak causes LH surge Progesterone Estrogen level very low Progesterone and estrogen promote thickening of endometrium Uterine (menstrual) cycle Endometrium Days Menstrual flow phase 0 5 Proliferative phase 10 Secretory phase 14 15 20 25 28

Fertilization and Implantation if pregnancy occurs Cleavage starts Cleavage continues Ovary Fertilization occurs The blastocyst implants Ovulation Uterus Endometrium From ovulation to implantation