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Unformatted text preview: occurs because of High PO2 in the aortic blood and bradykinin.
- now aortic pressure is greater than the pulmonary pressure – doesn’t like the high
oxygen tension starts to close
- progressively becomes ligamentum arteriosum. Fetal umbilical arteries constrict:
Fetal umbilical arteries constrict: prevents blood flow from the baby to the placenta : distal parts (parts going towards umbilicus) become medial umbilical ligaments inside the anterior abdominal wall : proximal parts becomes superior vesical arteries which supply the urinary bladder Fetal umbilical vein,- intra abdominal part becomes:
ligamentum teres of the liver
The vessel will be patent until couple of weeks after birth- useful for venous access in the new born.
A potential arteriole persists through out life. (note, C.M) No more mixing of oxygenated and deoxygenated blood
except a little in the lungs God Bless You To God Be The Glory On occlusion of placental circulation summary of structural changes in the fetal circulation after birth. • • Umbilical vein : becomes ligamentum teres of the liver
• Ductus venosus : ligamentum venosum
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- Winter '14