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Cards In This Set
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Outline the pathway for producing progesterone and estrogen.
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 Look at image |
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What is the role of the hypothalamus in regulating the ovaries?
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Pulsatile GnRH secretions stimulate anterior pituitary to secrete FSH and LH
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What is the effect of FSH and LH on the ovaries?
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Steroidogenesis in ovarian follicle and corpus luteum
Follicular development beyond the antral stage
Ovulation
Luteinization
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Actions of estrogen (there are lots):
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Has both negative and positive feedback effects on FSH and LH; causes maturation and maintenance of the fallopian tubes, uterus, cervix, and vagina; causes development of female secondary sex characteristics at puberty; causes development of breasts; up-regulates estrogen, LH, and progesterone receptors; causes proliferation and development of ovarian granulosa cells; maintains pregnancy; lowers uterine threshold to contractile stimuli during pregnancy; stimulates prolactin secretion (but then blocks its action at the breast)
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Actions of progesterone:
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Negative feedback effects on FSH and LH secretion during the luteal phase; maintains secretory activity of the uterus during the luteal phase; maintains pregnancy; raises the uterine threshold to contractile stimuli during pregnancy; participates in development of the breasts
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What are the phases of the menstrual cycle and at what day do they occur?
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Follicular phase (days 0-14); Ovulation (day 14); Luteal phase (days 14-28); Menses (days 0-4)
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When does a primordial follicle develop and how far does it develop during this phase?
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During the follicular phase; it becomes a graafian follicle
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What happens to FSH and LH receptors and in which cells during the follicular phase?
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LH and FSH receptors are up-regulated in theca and granulosa cells
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What happens to estradiol levels during the follicular phase and what do they do primarily?
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Estradiol levels increase and cause proliferation of the uterus
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What are progesterone levels like during the follicular phase?
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Progesterone levels are low
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What does elevated estradiol do to FSH and LH?
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FSH and LH are suppressed by negative feedback effect of estradiol on the anterior pituitary
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How does cycle length affect the day on which ovulation occurs?
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Ovulation occurs on 14 days before menses, regardless of cycle length
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What causes the LH surge?
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A burst of estradiol synthesis at the end of the follicular phase has a positive feedback effect on the secretion of FSH and LH
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What causes ovulation, directly?
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Ovulation occurs as a result of the estrogen-induced LH surge
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What happens to estrogen levels right after ovulation?
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They decrease right after ovulation, but increase later during the luteal phase
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