Major goal of fetal circulation
to get nutrients and oxygen to the brain and rest of body
which systems are not yet functional in fetus
pulmonary and digestive systems, lungs are still collapsed and fluid filled
how do fetus receive oxygen and nutrient?
from mothers placenta via diffusion
Fetal circulation: starting point
- Placenta- diffusion of wastes, oxygen and nutrients
oxygenated blood returns to fetus via….
umbilical vein
deoxygenated blood leaves fetus via…
umbilical arteries
getting to the heart: (most blood/ path 1)
Umbilical vein to ductus venosus and then to the inferior vena cava to heart (skips liver)
getting to the heart: (path 2)
umbilical vein to portal sinus to liver and then portal vein. to heart (provide oxygen to liver)
in fetal circulation what chamber does the blood enter….
right atrium
Fetal circulation: through the heart (after entering the right atrium)
- 30% of blood is shunted to left atrium via the foramen ovale
-70% of blood is pumped into right ventricle then to pulmonary artery then 90% of the blood enters the ductus arteriosus and is shunted to the aorta
what organ is bypassed in fetal circulation?
lungs
what structures helps to bypass the pulmonary circuit of. the fetus
-foramen ovale
- ductus arteriosus
what happens if ductus arteriosus fails to close after birth?
- blood will flow back from aorta into pulmonary arteries
