Female Reproductive Physiology Flashcards
oxytocin release during ____
parturition (childbirth)
LH surge that triggers ___
ovulation
GnRH stands for
Gonadotropin-Releasing Hormone
Hypothalamic-Pituitary-Ovarian (HPO) Axis releasing factor
Gonadotropin-Releasing Hormone (GnRH)
*from hypothalamus
Hypothalamic-Pituitary-Ovarian (HPO) Axis trophic hormones
Gonadotropins (“stimulate” gonads)
- Follicle-Stimulating Hormone (FSH)
- Luteinizing Hormone (LH)
*released from the anterior pituitary
Hypothalamic-Pituitary-Ovarian (HPO) Axis target hormones
ovarian hormones - released by ovaries
- Estrogens (“generators of sexual activity”)
- Progesterone (“progestational” hormone)
- Inhibins (regulatory peptide hormones)
key players in Hypothalamic-Pituitary-Ovarian
(HPO) Axis
GnRH
gonadotropins (FSH, LG)
ovarian hormones (estradiol E2, progesterone, inhibins)
Gonadotropin-Releasing Hormone (GnRH) is released from where?
hypothalamus
Gonadotropin-Releasing Hormone (GnRH) is released from the hypothalamus in response to what?
low E and P levels
Gonadotropin-Releasing Hormone (GnRH) stimulates the release of what?
FSH and LH
Follicle-Stimulating Hormone (FSH) is involved in follicular development and __ ___
steroid secretion
Luteinizing Hormone (LH) is involved in steroid secretion and ___
ovulation
Estradiol (E2) –
Progesterone –
Inhibins –
Estradiol (E2) – steroid hormone
Progesterone – steroid hormone
Inhibins – peptide hormones that
selectively inhibit FSH
what cells does the FSH hormone stimulate?
ovarian granulosa cells only
what cells does the LH hormone stimulate?
ovarian granulosa cells
ovarian thecal cells
thecal cells release what?
androgens
thecal cells release androgens, that get aromatized to what? where?
estrogens in granulosa cells?
____ feedback inhibits the HPO
axis
Estrogen
inhibin B is released by what?
granulosa cells
inhibin B hormones do what?
inhibit FSH secretion
During pregnancy, _____is the
predominant circulating estrogen in
terms of serum levels.
Estriol (E3)
After menopause, _____ is the
predominant circulating estrogen
Estrone (E1)
_____ is the predominant
estrogen during majority of the
reproductive years
Estradiol (E2)
functions of estrogens (7)
- Female sexual maturation & development of
secondary sex characteristics - Increases CNS excitability (Catamenial Epilepsy)
- Stimulate endometrial proliferation & uterine growth
- Maintenance of healthy blood vessels & skin
- Reduce rate of bone reabsorption.
- Alters plasma lipids
- increases HDL & triglycerides, while decreasing LDL levels)
- Enhances blood coagulability/blood clotting risk
follicular phase:
encompasses follicular development in the ovary
leading up to ovulation
1st day of menstrual cycle
(Days 1-5) During the follicular phase, low estrogen (E2) triggers
hypothalamic GnRH release, which stimulates the anterior pituitary to release FSH & LH
In the early follicular phase, _____ is released episodically at ~ 90 min intervals, resulting in pulses of ___ & ___ @ ~90 min intervals.
GnRH
FSH & LH
during the follicular phase, FSH & LH stimulate the growth of ’_____’ ovarian follicles into secondary follicles.
‘primordial’
As the follicular phase proceeds, LH
secretion slowly ______ and LH
pulses get faster (~60 min intervals) increasing E2 production.
increases
Around Day 5-7, a small ____ in E2 inhibits FSH & LH release, “starving” follicles of FSH
increase
Days 7 -14: Dominant ovarian follicle
_____ E2 production as it matures
increases
Uterine proliferative phase: E2
stimulates (2)
endometrial growth
vascularization
Day 14: High [E2] levels trigger “LH
surge” which will cause a momentary switch to
_____ feedback
positive
LH is building up in Ant Pit leading
up to Day ____
14
what is key for ovulation on day 14?
LH surge !
What causes the LH surge?
E2 levels reach a “tipping point” threshold, BRIEFLY flipping the HPO axis from negative to positive- feedback.
E2 stimulates the hypothalamus to release ____ GnRH to cause LH surge
more
____ stimulates Ant. Pituitary to release stored LH on day 14 (“LH surge”)
GnRH
A rapid drop in LH & FSH returns HPO axis to a ____ feedback after “surge”
negative