Reproductive Cycle Flashcards
HPG axis
Hypothalamus releases GnRH, anterior pituitary releases releases LH and FSH, and these hormones would stimulate ovaries to secrete estrogen and progesterone
3 phases of reproductive cycle
Follicular (from 1st day of menses to LH surge), LH surge in day 14, and luteal phase (begins with LH surge and ends with onset of menses)
Granulosa cells
Single inner later of immature oocyte. Produce estrogen, including estradiol and estrone
Theca cells
Produce androgen, which is the precursor for estrogen production by granulosa cells. Androgens enter granulosa by diffusion.
Hormone that binds to thecal cells
LH
Hormone that binds to granulosa cells
FSH
GnRH testing
Cannot be tested as it has a short half life. Can measure LH pulses to determine.
Ovary response to FSH and LH
With subsequent negative feedback, later in the follicular phase peak estrogen level from dominant follicle has positive feedback on pituitary which stimulates mid cycle LH surge
In terms of endometrium the phases are called…
Proliferative and secretory
What starts menses?
When conception doesn’t occur and corpus luteum involutes, and hence prog and est levels decrease
How long menses last on avg?
3to 7 days
What stops menses
Rising of estrogen in early follicular phase
Which mature follicle becomes dominant?
The one with grease number of granulosa cells, FSH receptors, and highest estradiol production
LH surge
Meiosis of primary follicle resumes and first polar body is released
Luteal phase
Switch from predominance from estrogen to progesterone
Progesterone
Has negative feedback on both FSH and LH
Progesterone secretion
Corpus luteum secretes another 6 to 7 wks after fertilization and then placenta takes over the job
Proliferative phase of endometrium
Estrogen is the dominant hormone. Stimulates endometrial cell growth, in ovulatory phase the thickness reaches it’s max
Secretory phase of endometrium
Progesterone is the dominant hormone. Makes endometrial layer edema toys and loose. Blood vessels in the endometrium are thickened. With the withdrawal of progesterone, Menses begin.
Anovulation
If ovulation does not occur, estrogen continues to be produced and endometrium continues to thicken. Endometrium eventually outgrows it a blood supply and sections of it slough off intermittently. Without progesterone withdrawal it doesn’t happen all at once, so you have abnormal uterine bleeding.
Endocervix
Produces a lot of clear mucus during estrogen secretion (follicular phase) and reaches its peak at ovulation.
Breast changes with reproductive cycle
Progesterone during LH phase increase ductal and glandular tissue on breast = breast enlargement and tenderness
Progesterone and temp
Increases temp by .5 to 1 F
