Lecture 21 - Pregnancy and Menopause

Question 1

early phases of pregnancy

Answer 1

1. zygote
2. 4-cell stage
3. morula
4. early blastocyst
5. implanting blastocyst

Question 2

blastocyst and implantation: what is syncytiotrophoblast

Answer 2

invasive cell
produce hCG (human chorionic gonadotropin) which is the marker used in pregnancy tests

Question 3

hCG binds…

Answer 3

LH receptors of granulosa cells and rescues corpus luteum
* corpus luteum survives until 8th week of pregnancy when placenta takes over

Question 4

function of hCG in placenta

Answer 4

favors angiogenesis and correct development of placenta

Question 5

function of hCG in fetus

Answer 5

• health indicator: low on ectopic pregnancy and spontaneous miscarriages, double regular levels in down syndrome fetuses
• male fetus: hCG interacts with LH receptors on leydig cells, stimulates T synthesis which promotes growth of male reproductive tract

Question 6

function of hCG unrelated to pregnancy

Answer 6

elevated conc. in non-pregnant ppl linked to cancer

Question 7

to maintain pregnancy, what must be higher

Answer 7

progesterone must be higher than estrogen

Question 8

progesterone is produced by

Answer 8

corpus luteum durign first 8-10 weeks
but later produced by placenta

Question 9

effects of progesterone during pregnancy

Answer 9

decreases contract of smooth muscle
decrease prostaglandin production in smooth muscle
protects fetus and prevent further fertilization: makes thick cervical mucus
suppresses immune response
increases ventilation
increases appetite to facilitate deposition of substrates
* develops breast for lactation*

Question 10

which estrogen is high during pregnancy

Answer 10

estriol (E3)
synthesis by corpus luteum and then placenta

Question 11

estrogen production in fetus

Answer 11

• placenta produces pregnenolone
• fetal adrenal gland converts it into DHEA-S
• felal liver modifies it to 16alpha-DHEAS-S
• placenta has enzymes required for completing synthesis of estrogens

Question 12

why is estriol so important during pregnancy

Answer 12

bc it is as potent as estradiol in maintaining blood flow to placenta, but has minimal effects on myometrial contractility

Question 13

estrogen effects during pregnancy

Answer 13

• growth of myometrium
• breast develppment
• stimualtes prolactin
• stimualtes protein synthesis in liver
• labor and delivery

Question 14

the human placental lactogen is secreted

Answer 14

by placenta and reaches extremely high conc in the 3rd trimester
* also has metabolic effects

Question 15

the human placental lactogen is secreted

Answer 15

by placenta and reaches extremely high conc in the 3rd trimester
* also has metabolic effects

Question 16

what are the metabolic effects of hPL

Answer 16

anti-insulin effects:
* stimulates lipolysis in maternal adipose tissue
* inhibits insulin stimulated glucose uptake in maternal target tissues
* stimulates proteolysis

Question 17

menopause

Answer 17

• caused by depletion of follicles
• decrease in critical mass, which determines # of follicles in cohort of pre-antral follicles
• disturbs timing between ovarian steroid synthesis and pituitary FSH/LH secretion

Question 18

thecal cells =

Answer 18

ovarian tissue

Question 19

granulosa cells =

Answer 19

follicular tissue

Question 20

during menopause, there are no more

Answer 20

granulosa cells and no more ovarian aromatase so no more ovarian E2. however the aromatase in peripheral tissues will continue to make estrone

Question 21

during menopause there is higher levels of

Answer 21

FSH than LH which means there is no inhibin and thus a decrease in E

Question 22

hormonal patterns post-menopause

Answer 22

• marked drop in plasma estradiol (E2)
• estrone (E1) > estradiol (E2) which is derived from peripheral non-ovarian tissues
• marked elevation in FSH and LH; FSH>LH since no longer suppressed by inhibin
• plama androgens concentrations remain close to pre-menopause levels