reproduction/gondal Flashcards
(91 cards)
where does HCG come from?
the implanted embryo releases HCG
HCG causes hyperemesis = N+V during pregnancy
what use is HCG in practice?
hormone used in pregnancy test
Human Placental Lactogen (HPL) is secreted from where?
the placenta
also secretes placental progesterone + placental oestrogen
what does HPL do apart from breast development?
causes insulin resistance in mother
along with placental progesterones
what hormone does the follicle secrete?
ostradiol
what hormone does the corpus luteum (fertilised ovum) secrete?
progesterone
what week of pregnancy does organogenesis start?
week 5 probs earlier
what increases thyroxine in pregnancy?
HCG - excessive hCG mimics hyperthyroidism
increased thyroxine suppresses TSH
function of follicle stimulating hormone in males + females
male - causees testes to produce sperm (spermatogenesis)
female - causes growth of ovarian follicles (oogenesis) + ovary to secrete oestrogen
luteinizing hormone effect in males + females
male - causes testes to secrete testosterone
female - causes ovulation + causes progesterone production by corpus luteum
how does the pulsatile manner of GnRH release differ between males and females?
males - pulses at constant frequency
females - frequency of pulses varies during menstrual cycle
follicular = high frequency luteal = low
does a high frequency of GnRH pules favour LH release or FSH?
LH pulses
low frequency = FSH pulses
effect of oestrogen + progesterone on GnRH pulses?
high oestrogen increases GnRH pulses - increasing LH release
high progesterone reduces GnRH pulses
where are oestrogen and progesterone receptors that influence GnRH pulses found?
kisspeptin neurones - these indirectly influence GnRH neurones
where is oestrogen secreted from?
primarily by ovaries (follicles) + adrenal cortex
and placenta in pregnancy
functions of oestrogen (4)
increase thickness of vaginal wall
regulate LH surge
reduce vaginal pH through increase in lactic acid production
decrease viscosity of cervical mucus to facilitate sperm penetration –> FERTILE mucus
where is progesterone secreted from?
corpus luteum + placenta during pregnancy
function of progesterone (5)
“pro-gestation” (maintain pregnancy)
- responsible for INFERTILE thick mucus - prevents sperm transport + infection
- maintain thickness of endometrium
- relaxes myometrium (smooth muscle)
- inhibits secretion of LH
- increase basal body temp
what does the LH surge lead to?
ovulation
regulates formation of corpus luteum
regulates progesterone production + secretion
–> increasing progesterone decreases LH secretion by influecing GnRH pulses
LH surge
preceds ovulation by approx 34-36hrs
thershold of oestrogen (200pg/ml) is required for LH surge - via increase GnRH pulses
increase LH levels -> progesterone levels begin to increase
which follicular cell expresses LH receptors?
theca cells - release androgens in response to LH
which follicular cell expresses FSH receptors?
granulosa cella
folliculogenesis
early stages occur independently of gonadotrophins, once follicle is certain size becomes gandotrophin dependent (MUST coincide with rise in FSH during early follicular phase
describe the formation of corpus luteum
occurs under influence of LH
granulosa + theca cells transform to luteal cells
increase in progesterone production (via increased cholesterol - substrate for progesterone synthesis)