Fetal Circulation Before Birth Flashcards
What is the ductus venosus?
A little blood vessel that sits in the liver & branches off the umbilical vein
It connects to the inferior vena cava And passes oxygenated blood through to create mixed oxygenated blood.
What are the adaptations of the fetal circulation?
Umbilical vein ( from the placenta to the liver)
Ductus venosus ( branches off from the umbilical vein in the liver to the inferior vena cava)
Foramen ovale ( opening to allow blood to flow from the right atrium to the left atrium) Reduces pressure in the right atrium
Ductus arteriosos ( allows blood to flow from the pulmonary artery to the aorta) helps to reduce high pressure in the pulmonary artery
Umbilical artery ( brings mixed oxygenated blood back to the placenta )
What is hypoxic pulmonary vasoconstriction?
when the small pulmonary arteries constrict due to low oxygen levels
Results in blood being redirected due to there being a lot of pressure in the lungs
What happens to the right side of the heart as a result of pressure being built up in the pulmonary arteries?
A lot of pressure builds up in the right atrium and right ventricle
What is the reason that not a lot of blood flows through the pulmonary veins back into the heart?
Blood takes the path of least resistance
The ductus arteriosis causes blood to flow from the pulmonary artery into the aorta
Foramen ovale allows blood to flow into the left atrium from the left atrium
What does the umbilical artery do?
Brings blood back towards the placenta
Why does blood direct towards the placenta?
The placenta has a low resistance which causes blood to direct towards it
