Endocrinology of female reproduction

Question 1

basics of female reproduction

Answer 1

cyclical fertility, 3-5 days per month from puberty
~7 million follicles in utero, decreases to ) at menopause
~400 follicles are ovulated

Question 2

how is the ovarian reserve formed

Answer 2

primordial germ cells colonise the gland
numbers expand by meiosis
germ cell enter, then arrest in meiosis
primordial follicles form
folliculogenesis

Question 3

what do ovaries secrete

Answer 3

the female sex hormones

Question 4

what is the action of oestradiol

Answer 4

endometrial proliferation during endometrial proliferation
female genital development
secondary female sex characteristics (breast development, body fat distribution, epiphyseal closure)

Question 5

what is the action of progesterone

Answer 5

endometrial secretion and vascularisation during menstrual cycle (prep uterus for pregnancy)
maintain pregnancy and support uterus (produced by corpus luteum at start, but if pregnancy occurs main source of progesterone comes from placenta)

Question 6

how does hormonal contraception work

Answer 6

manipulation of steroid gonadal hormones
suppress ovulation via negative feedback of progesterone
oestrogen in combined pill provides additional feedback and promotes progesterone receptor expression
secondary effects on female genital tract

Question 7

what is the function of anti-mullerian hormone

Answer 7

made by granulosa cells
absent in promordial follicles but present in later stages
inhibitory effect of follicle development
unaffected by gonadotrophins/steroid hormones

Question 8

what can AMH be a reliable reflection of

Answer 8

growing follicles
(not a perfect method)

Question 9

what does the ruptured follicle develop into

Answer 9

corpus luteum (granulosa and theca cells)

Question 10

what are the lutein cells

Answer 10

mitochondria
smooth er
golgi
lipid droplets
pigment lutein

Question 11

what is lutenisation

Answer 11

progesterone secretion

Question 12

what does suckling do

Answer 12

sends nerve impulses to brain causing release of prolactin and oxytocin

Question 13

what is the function of prolactin

Answer 13

alveoli swell and secrete milk
steroid block at placental prevents this prior to birth
negative feedback on FSH and LH levels

Question 14

what is the function of oxytocin

Answer 14

major effects on smooth muscle contraction and myoepithelial cell contraction around alveoli causing milk expulsion (milk ejection reflex)
used to induce labour

Question 15

what are hormone levels after menses

Answer 15

FSH levels drop due to negative feedback
oestrogen levels rise
this causes the endometrium to thicken

Question 16

what does the rise in oestrogen stimulate

Answer 16

LH release from the pituitary
as the follicle grows it produces more oestrogen, at a certain threshold its effect reverses, it now has a positive effect on secretion of FSH from pituitary
together FSH and oestrogen stimulate LH binding sites on outer layers of granulosa cells

Question 17

what causes release of oocyte from the follicle

Answer 17

LH surge on ~day 14
oestrogen drops as follicle is gone, the corpus luteum produces some

Question 18

what does the follicle become once the oocyte is released

what are the hormone levels

Answer 18

corpus luteum (detection of ovulation)
fall in FSH/LH, negative feedback
progesterone levels continue to rise
progesterone completes endometrium

Question 19

what happens if pregnancy does not occur

Answer 19

corpus luteum regresses
FSH begins to rise
progesterone and oestrogen drop
endometrium is shed