B8-016 Physiology of Pregnancy Flashcards
[…] volume and […] resistance blood flow to placenta
high volume and low resistance blood flow to placenta
stem cells of placenta
cytotrophoblast
major transport layer of the placenta
syncytio-trophoblast
send out invasive cytotrophoblasts that eventually reach the spiral arteries, remodeling them and allowing for higher blood flow
anchoring villus
cytotrophoblast remodeling of spiral arteries allows for increased […] and decreased […]
volume
resistance
major hormones produced by the placenta/trophoblasts [4]
chorionic gonadotropin (CG)
placental lactogen (PL)
progesterone
estrogens
detectable in maternal serum 7-9 days following the midcycle LH surge
hCG
expressed 5-10 d after conception;
in maternal serum 3 weeks after fertilization
PL
hCG is present through pregnancy but peaks about week […]
10
hCG binds to […] receptors
LH
half life of hCG is
hours
(as opposed to LH which only lasts minutes)
maintains function of the corpus luteum and progesterone production for the first 7 weeks
hCG
placental lactogen is structurally very similar to
growth hormone
PL can bind to […] receptors [2]
GH
PRL
(regulates metabolism and mammary glands)
the placenta lacks […] to make DHEA
cyp17
cannotsynthesize androgens
the placenta receives DHEA-S from [2]
maternal circulation
fetus
(via adrenals)
myometrial contraction is inhibited by
P4
myometrial contraction is stimulated by
estrogens
cervical maturation is inhibited by
P4
cervical maturation is promoted by [3]
E
Relaxin
PGE2
maintains uterine quiescence
antagonizes estrogens actions
progesterone
source of hCG and PL
syncytiotrophoblasts of the placenta
inhibits the myometrial contractability and softens the cervix for birth
relaxin
stimulates uterine contractions via gap junctions and induces the expression of oxytocin receptors
estrogens
stimulates cervix softening and uterine contractions
prostaglandins (PGF2a)
major contractile hormone
oxytocin
increase in secretion of CRH from the placenta stimulates [2]
fetal DHEA production
prostaglandin production
describe the ferguson reflex
oxytocin induces myometrial contractions –> cervical stretch
cervical stretch exerts positive feedback on supraoptic nuclei in hypothalamus to secrete more oxytocin –> progress labor
inhibit milk synthesis [2]
estrogen
progesterone
functions in mammary gland duct growth and fat deposition
estrogen
functions in the growth of the alveolar epithelium
progesterone
function in growth of the mammary gland and milk synthesis [3]
PRL
GH
PL
induces transcription of PRL synthesis and increases number of lactotropes during pregnancy
estrogen
stimulates milk secretion and lipase activity
prolactin
propels milk through the ducts to nipples via contraction of the myoepithelium
oxytocin
prolactin is under dominant inhibition via
dopamine
after delivery, the main stimulator of prolactin synthesis is
suckling stimulus
high levels of […] can cause amenorrhea while breastfeeding
prolactin
main stimulus for oxytocin release
suckling
hormone responsible for the establishment and maintenance of pregnancy in early weeks
extends luteal phase until placenta can make its own progesterone
hCG
placental delivery removes the block progesterone and estrogen have on
milk synthesis
endometrial reaction at implantation
decidual reaction
[…] is produced by the placenta immediately after implantation to prevent regression of the corpus luteum
stimulates production of estrogen and progesterone
hCG
the […] takes over production of progesterone and estrogen after the first trimester
placenta
synthesized from syncytiotrophoblast after fertilization
hCG
hCG is structurally similar to [3]
LH
FSH
TSH
(all four share the same alpha subunit, beta subunit differentiates them)
oxytocin is stored in the […] pituitary gland
posterior
oxytocin is produced in the […] nuclei of the hypothalamus, then stored in the […] gland
paraventricular (preoptic)
posterior pituitary (herring bodies)
stored in the posterior pituitary in specialized nerve endings called Herring bodies
oxytocin
acts on the uterus to increase contraction during childbirth
oxytocin
acts on the mammary glands to induce milk let down in breastfeeding mothers
oxytocin
inhibits secretion of GnRH from the hypothalamus during breastfeeding
prolactin
symptoms of global hypopituitarism
fatigue
anorexia
poor lactation
loss of pubic/axillary hair
(suspect Sheehan syndrome)
what hormones inhibit lactation in pregnancy? [2]
estrogen
progesterone
stimulates mammary gland development during pregnancy
estrogen
stimulates growth of alveolar epithelium during pregnancy
progesterone
stimulates pituitary lactotrope proliferation and prolactin synthesis during pregnancy
estrogen
during weeks 6-8 of pregnancy, hCG produced by the placenta stimulates […] secretion by the corpus luteum
progesterone
[…] secretion by the ovary is required to maintain pregnancy during weeks 6-8
progesterone
when does the placenta begin to synthesize/secrete its own progesterone?
week 7ish
when is placental production of progesterone sufficient to maintain the pregnancy on its own?
weeks 8-10
inadequate levels of hCG or placental production of progesterone after week […] will result in pregnancy loss
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