hormones in menstruation and pregnancy Flashcards
what are the two phases of menstrual cycle
follicular
luteal
what hormone stimulates follicular development
FSH
what secretes FSH and LH
anterior pituitary
what hormone stimulates FSH and LH to be released and where does it come from
GnRH from hypothalamus
what does the follicle secrete
oestrogen
what effect does oestrogen have on FSH
negative feedback - increasing oestrogen decreases FSH
what effect does oestrogen have on LH
positive feedback - increasing oestrogen increases LH
what is ‘LH surge’
peak conc of LH which stimulates ovulation
effect of LH on follicle
causes it to release oocyte
promotes formation of corpus luteum
what does corpus luteum secrete
progesterone (and some oestrogen)
role of progesterone
prepares endometrium for implantation maintains endometrium in early pregnancy increases basal body temp relaxes smooth muscle produces thick cervical mucous
if no implantation occurs, what happens
triggers corpus luteum regression
effect of corpus luteum regression
decreased progesterone and oestrogen conc
increase in FSH conc
if implantation occurs, what hormone signals corpus luteum to stay alive
HCG produced by placenta
what other hormones does placenta produce
HCS - promotes protein tissue formation (breast enlargement)
progesterone
oestrogen
after birth, what does decreased oestrogen production cause
increase in prolactin - prepare for breastfeeding
role of oestrogen
endometrial thickening
produces thin cervical mucous
increased sodium and water reabsorption in kidneys
increased water conc in uterus
what hormonal changes occur in pregnancy
diabetic (increased insulin resistance)hyperparathyroid hyperthyroid hyperoestrogenic hyperprogesterogenic hypertensive
effect of progesterone in pregnant ladies
development of decidual cells
decreases uterus contractility
preparation for lactation
effect of oestrogen in pregnant ladies
enlargement of uterus
breast development
relaxation of ligaments
what does the estriol level indicate
if high, may indicate congenital abnormalities e/g/ down’s syndrome
when does ovulation occur
14 days before next menses
how long before ovulation does LH surge occur
24-36 hours
how quick and by how much does HCG increase
doubles 50% in 48 hours
