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12 Cards in this Set
- Front
- Back
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Pre-Natal |
Before Birth |
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Pre-Natal Step 1 |
Oxygenated & Nutrient-Rich blood from placenta passes to the fetus via umbilical vein, located in umbilical cord |
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Pre-Natal Step 2 |
~1/2 of this blood bypasses the liver via Ductus Venosus and enters Vena Cava. The remainder enters the portal vein to supply the liver with nutrients and oxygen. |
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Ductus Venosus |
A duct that passes through the liver |
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Pre-Natal Step 3 |
Blood entering RA from Inferior VC (brings blood back to heart from lower body) bypasses the V lungs are not functioning yet) to enter LA via Foramen Ovale |
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Pre-Natal Step 4 |
Blood from Superior Vena Cava (VC) (bringing blood back to heart from upper body) enters Right Atrium (RA), passes Right Ventricle (RV) and moves to Pulmonary Trunk. Most blood in pulmonary trunk enters aorta via Ductus Arteriosus |
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Pre-Natal Step 5 |
Partially oxygenated blood in aorta returns to the placenta via paired umbilical arteries that arise from internal illiac arteries and then pass through the umbilical cord to the placenta |
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Key Point for Pre-Natal Circulation |
Blood circulating through fetus is only partially oxygenated |
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Post-Natal |
After Birth
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Post-Natal Step 1 |
As pulmonary respiration begins at birth, pulmonary BP fails, causing blood from Right pulmonary trunk to enter the pulmonary veins instead of passing to the aorta, which will now have higher pressure |
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Post-Natal Step 2 |
Foramen Ovale and Ductus Arteriosus close, eliminating fetal right to left stunts. Pulmonary & systemic circulations in heart are now separate |
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Post-Natal Step 3 |
As the infant is separated from the placenta, the umbilical arteries no longer function, along with umbilical vein and ductus venosus |
