Ovulation - , under the direction of LH, the remaining...

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Ovulation Ovulation occurs on day 14. As the amount of estrogen in the blood increases prior to ovulation, it signals the hypothalamus to release GnRH and the anterior pituitary gland to release LH. Just before ovulation, there is a surge of LH. LH increases the blood flow to the follicle which causes it to swell. Additionally, LH signals the secretion of collagenase and plasmin to enzymatically degrade the connective tissue and proteins surrounding the follicle and ovary. As the ovarian and follicular walls weaken, the follicular fluid, corona radiata cells and the secondary oocyte (surrounded by a zona pellucida ) are released from the ovary and are swept into the uterine tube by the fimbriae . Postovulatory Phase After ovulation, the ovary continues to play a role in the sexual cycle. During the luteal phase
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Unformatted text preview: , under the direction of LH, the remaining follicular cells develop into a corpus luteum . The corpus luteum begins to secrete progesterone, which continues the development of the uterus . If fertilization and implantation does occur, the implanted zygote secretes human chorionic gonadotropin , which signals to the corpus luteum in the ovary to continue to secrete estrogen and progesterone throughout the first trimester of pregnancy. In the absence of this signal, the ovary enters the premenstrual phase and the corpus luteum degrades into a corpus albicans . The decreased secretion of progesterone from the corpus luteum results in atrophy of the endometrial lining and menstruation....
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