Fetal circulation 264

Question 1

Blood in umbilical vein

Answer 1

Has a P02 of =30mmHg and is =80% saturated with oxygen. umbilical arteries have low oxygen saturation.

Question 2

blood entering fetus through the umbilical vein is conducted via

Answer 2

The ductus venous into the IVC, bypassing hepatic circulation

Question 3

Most of the highly oxygenated blood reach the heart via

Answer 3

the IVC is directed through the foramen ovale and pumped into the aorta to supple the head and body

Question 4

Deoxygenated blood

Answer 4

from the SVC passes through the RA–RV–main pulomanry arterty–patent ductus arteriosus
descending aorta; shunt is due to high fetal pulmonary artery resistance( due partly to low oxygen tension)

Question 5

Indomethacin

Answer 5

helps close PDA—ligamentum arteriosum( remnant of ductus arteriosus)

Question 6

prostaglandins E1 and E2

Answer 6

keeps PDA open

Question 7

when at birth infant takes abreath

Answer 7

resistance will decrease in pulmonary vasculature
increase left atrial pressure vs right atrial pressue
foramen ovale closes( now called fossa ovalis)
increase in oxygen(from respiration) and decrease in prostaglandins(from placental separation)—closure of ductus arteriosus