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Fetal Circulation. Some key features & differences…. Important Structures. Ductus Arteriosus Runs from pulmonary artery to aorta Bypasses lungs in fetus Collapses at birth due to demand of lungs for blood. Foramen Ovale Left & right atria both have a “hole” in inside wall
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Fetal Circulation Some key features & differences…
Important Structures • DuctusArteriosus • Runs from pulmonary artery to aorta • Bypasses lungs in fetus • Collapses at birth due to demand of lungs for blood
Foramen Ovale • Left & right atria both have a “hole” in inside wall • Allows blood to flow from right to left atria bypasses lungs! • Expansion of left atrium at birth puts 2 holes out of alignment
DuctusVenosus • Stops carrying blood from moment of birth • Channel through liver that carries blood from placenta to inferior vena cava • Approx ½ blood enters liver • Approx ½ blood bypasses liver ductus venosus inferior vena cava heart
Umbilical Artery • Carries blood LOW in oxygen/nutrients from baby to mom • Umbilical Vein - Carries blood RICH in oxygen/nutrients from mom to baby
Key Differences • Umbilical vein transports oxygen rich blood to the fetus • Fetal blood has a much greater capacity to carry oxygen • Vein carries blood to the liver and is partially shunted by the ductusvenosus this allows about half the blood to bypass the liver! • The ductus joins the inferior vena cava • Blood from the lower part of the fetal body is mixed with oxygen rich blood from the placenta
Blood is forced into the right atrium. • The fetal heart has an opening between the right and left atria that shunts blood away from the lungs. • This opening is called the foramen ovale. • The ductusarteriosus conducts blood away from the pulmonary trunk to the aorta (lung bypass).