Male and Female Gonad Physiology Flashcards
(21 cards)
Which cells in the testes produce testosterone and how is it regulated?
Leydig cells and regulated LH via pituitary, and GnRH via hypothalamus (mediated by the chemical from the conversion of T to E2)
T in pituitary inhibits the synthesis of LH-beta subunit
Inhibin and activin locally regulates GnRH
Which hormones are measured to assess male gonadal failure?
Testosterone and LH
Describe the hormonal levels in primary testicular failure:
low T, high LH
Describe the hormone levels in pituitary failure:
low T, low LH
Which cells and hormone help in spermatogenesis?
Sertoli cells and FSH
What condition is necessary for spermatogenesis to occur?
high intratesticular levels of testosterone
Which cells make inhibin b?
Sertoli Cells
What can a small testes mean from a physical exam?
loss of seminiferous tubules or leydig cells
How does prolactin interact with the male repro system?
Increased prolactin inhibits LH/FSH release, leading to low testosterone/sperm production
What is the condition when LH is high, FSH is low, and T is low, and small testes?
Fertile eunuch syndrome (eventually will lead to complete testicular failure)
What forms of testosterone is bioavailable?
Albumin-bound, and free floating
SHBG-bound not active for use
True or false obesity affects obesity decreases SHBG and may erroneously indicate hypogonadism ?
True
What kind of serum testosterone should be measured in obese people?
bioavailable T (albumin and free) or free T
True or False: free Testosterone levels change with changes in protein bound T
False
Which cells in the ovaries convert cholesterol to create testosterone and intermediates for estrogen?
Theca Cells
What cells in the ovaries produce estrogen (estradiol)?
Granulosa cells
True or False corpus luteum produces progesterone
True
List the steps and hormones involved leading to ovulation:
Cohort of secondary follicles recruited – initiated by rise in FSH + loss of negative feedback to gonadal steroids and inhibin A
Selection of one dominant follicle –rising E2 and inhibin A (from follicle) restrain FSH rise so only one follicle develops
Further growth dominant follicle: E2, inhibin A increase exponentially, follicle acquires LH receptors
Exponential rise in E2 triggers POSITIVE FEEDBACK in hypothalamus leading to LH (and FSH) surge, triggering ovulation and luteinization of granulosa cells
What are the effects of progesterone on other hormones?
inhibits GnRH, LH, and FSH production and maintains the endometrium (by making glandular and vascular and secreting nutritious fluid for embryonic development)
How does is the endometrium maintained after egg is fertilized?
blastocyst/trophoblast secretes hCG which binds to LH receptors in corpus luteum, stimulating progesterone and E2 secretion
These maintain the endometrium until implantation and placenta takes over hormone production
What is tbe hormonal feature of menopause?
high FSH and low E2
