Physiology of Fetus and Placenta Flashcards Preview

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Flashcards in Physiology of Fetus and Placenta Deck (28):
1

Three fetal ducts that maximize blood flow to fetus brain and coronary arteries and circulation

Placenta --> umbilical vein (most oxygenated) --> shunted past liver via ductus venosus --> IVC --> right atrium (some mixing of blood) --> 1, new blood from IVC: foramen ovale --> left atrium --> left ventricle --> aorta --> brain and 2, deox blood from brain: right ventricle --> pulmonary artery --> ductus arteriosius -->descending aorta --> umbilical arteries --> placenta

2

Which fetal vessel has the most oxygenated blood for fetus

umbilical vein

3

Which fetal vessels take blood to the placenta

umbilical arteries

4

Where in the fetal heart is blood mixed?

right atrium --> return blood from brain and higher oxygen "fresh" blood from IVC --> some mixing but currents ensure most brain blood gets to right ventricle and most fresh blood gets to left atrium

5

When baby is born and cord is clamped ____ regresses

ductus venosus

6

When baby is born and takes first breath ____ dilate and ____ constricts.

vessels going to lung dilate and ductus arteriosus constricts

7

How does fetus avoid rejection by mother

HLA-G is not recognized by nonself MHC I and protects against NK cell attack

8

_____ is the primary site of placental hormone production

syncytiotrophoblast

9

HCG

single alpha subunit common to LH/FSH/TSH --> chr6; cluster of 7 beta units, chr19

10

T/F women in early pregnancy can be hyperthyroid

T --> because of shared alpha subunit with HCG

11

When can hCG be detected in maternal serum?

8 days after ovulation

12

After implantation, _______ produce most of the fetal hCG

villous syncytiotrophoblast

13

maternal serum levels of hcg _____ every 1.4 days during pregnancy

double --> peak at 10 weeks and the ndecline

14

Roles of hCG

maintain corpus luteum --> LH/CG receptor activates adenylyl cyclase and steroidogeneis; binds to TSH receptors

15

T/F antisera to hCG in early gestation causes pregnancy termination

T

16

____ test helps distinguish between intrauterine and ectopic pregnancy

hCG doubling time + ultrasound

17

MMS: multiple marker screening

bunch of fetal proteins that can be screened that indicate potential genetic issues

18

T/F fetal and placental compartments must work together to make estrogen because each are missing one enzyme.

T

19

Fetal adrenal makes ___ which goes to the placenta to be made into _____

dhea and estradiol

20

T/F fetus never makes cortisol

T --> no negative feedback to fetal pituitary so always pumping out DHEA

21

Placenta is the major source of _____

progesterone

22

2 roles of progesterone

during luteal phase, prepares endometrium for implanation, and prevents maternal immune rejection of trophoblast (because inhibits hte production of cytolytic cytokines)

23

T/F progesterone is a smooth muscle relaxant

prevents gap junction formation in muscle, reduces calcium channel synthesis, and decreases oxytocin receptors --> reduces muscle tone --> side effects = heartburn, urine stasis/utis, etc

24

____ estrogen is almost exclusively derived from fetal adrenal while ____ estrogen is equivalently derived from maternal and fetal systems

estriol vs estradiol

25

2 zones of fetal adrenal cortex

thick inner fetal and thin outer definitive zones

26

Thick inner fetal zones

>80% of the bulk of the gland, rapidly involutes after delivery, produces lots of DHEA, minimal production of cortisol

27

______ stimulates fetal adrenal to conduct steroidgenesis

ACTH --> not inhibited because of low fetal cortisol + placental deactivation of maternal cortisol

28

Actions of estrogens

fetal control of maternal physiology, vasodilation of spiral arteries, parturition (placental CRH, myometrial gap junctions, mammary epithelial proliferation)