foetal circulation

Question 1

ductus arteriosus

Answer 1

the foetal blood vessel that enables blood in th epulmonary artery to bypass the lungs and flow directly to the aorta

Question 2

ductus venosus

Answer 2

the foetal blood vessel that enables blood to bypass the liver

Question 3

foramen ovale

Answer 3

an opening in the atria of the heart, it allows blood to flow from the right atrium to the left atrium

blood entering right atrium is high in oxygen so it can bypass the lungs

Question 3

flow of blood in foetal circulation

Answer 3

placenta - umbilical vein - ductus venosus - inferior vena cava - right atrium (-pulmonary artery - lungs - left atrium) - aorta - descending aorta - umbilical arteries - back to placenta

Question 4

why can blood bypass the liver and heart

Answer 4

because they aren’t in function and only need small amounts of blood to support cell growth

Question 5

why do changes to the circulation occur at birth

Answer 5

the newborn can no longer rely on the placenta so the lungs and liver must become functional therefore blood needs to flow through

Question 6

when do the first breaths of life occur

Answer 6

usually the shock of birth
resus bag
clamping of the cord to build up CO2

Question 7

how does the ductus venosus change after birth

Answer 7

as blood is no longer flowing through the umbilical vein, and passes through the liver instead, it constricts and becomes a ligament

Question 8

how does the ductus arteriosus change after birth

Answer 8

lungs ar now functional which increases the pressure and decreases the resistance for the blood to flow to the lungs, so it constricts and becomes a ligament

Question 9

how does the foramen ovale change after birth

Answer 9

increased pressure in the heart due to larger amounts of blood returning, the difference in pressure of atria when lungs are functional causes the flaps to close against the wall

6-8W until its permanently

Question 10

why does a newborn have a rapid heart rate

Answer 10

because more oxygen is required for muscular activity and to keep it warm outside the uterus