Hormone feedback loop mechanisms and reproductive cycle physiology tested on USMLE Step 1, distinct from the disease-focused Endocrine and Reproductive Medicine decks.
34 cards · basic cards · AI-written, checked twice. Edit anything.
- In the HPA axis, the hypothalamus releases ____, which stimulates the anterior pituitary to secrete ACTH.
- CRH
- What is the principal negative feedback target of cortisol in the HPA axis?
- The hypothalamus and anterior pituitary (suppressing CRH and ACTH release)
- In the HPT axis, TRH from the hypothalamus stimulates the anterior pituitary to release ____.
- TSH
- What effect do circulating T3 and T4 have on TSH and TRH secretion?
- Negative feedback, they suppress TSH and TRH release
- What pattern of GnRH secretion is required to stimulate normal LH and FSH release?
- Pulsatile secretion
- What happens to LH and FSH secretion when GnRH is given continuously instead of pulsatile?
- LH and FSH secretion decreases due to receptor downregulation
- Which hormone surge directly triggers ovulation?
- LH surge
- Under what estrogen condition does estrogen switch from negative to positive feedback on GnRH and LH release?
- When estrogen is high and sustained for about 48 hours, in the late follicular phase
- What effect does estrogen have on gonadotropin release at low to moderate levels?
- Negative feedback, it suppresses LH and FSH release
- How does progesterone affect GnRH pulse frequency during the luteal phase?
- It decreases GnRH pulse frequency (negative feedback)
- Which ovarian cell type is the principal target of FSH?
- Granulosa cells
- According to the two cell, two gonadotropin theory, theca cells make androgens under LH stimulation, which granulosa cells convert to ____ under FSH stimulation.
- estrogen
- What enzyme converts androgens to estrogens in granulosa cells?
- Aromatase
- What is the function of inhibin B secreted by granulosa cells?
- It selectively inhibits FSH secretion
- Which four hormones share a common alpha subunit?
- LH, FSH, TSH, and hCG