Foetal circulation Flashcards
1
Q
how much blood travels to lungs in foetal circulation?
A
only 15% as the rest is bypassed via foramen ovale & ductus arteriosus
2
Q
why do you want to bypass lungs?
A
they are fluid filled and pul vasculature is constricted
3
Q
what happens after birth to circulation?
A
pulmonary vascular resistance falls –> increased blood flow to lungs –> increased blood flow to LA –> ductus arteriosus and foramen ovale close
4
Q
what is foramen ovale?
A
small hole in the septum between 2 atria
5
Q
what is ductus arteriosus?
A
duct connecting pulmonary artery with proximal descending aorta
6
Q
what is the 3rd foetal shunt and what happens to it?
A
ductus venosus- connects umbilical vein & IVC to bypass liver
closes when umbilical cord cut
