Fetal Circulation Flashcards
Blood in the Umbilical vein has a Po2 of
30mmHg
Blood in the Umbilical vein has an O2 saturation of
80%
Umbilical arteries have a
low oxygen saturation
Describe the Fetal Circulation 3 important shunts
1) blood entering fetus through the umbilical vein is conducted through the ductus venosus into the IVC bypassing hepatic circulation
2) most of the O2 rich blood reaching the heart via the IVC is conducted through the Foramen Ovale and pumped into the aorta to reach the head and body
3) Deoxygenated blood from the SVC passes through the RA -> RV -> through the main pulmonary artery-> ductus arteriosus -> descending aorta
Fetal shunts result from
high fetal pulmonary artery resistance (partly due to low O2)
Changes occurring in Fetal Circulation at birth
infant takes a breath -> decrease resistance in pulmonary vasculature -> increase in left atrial pressure vs right atrial pressure -> foramen ovale closes ->increased O2 from respiration and decrease prostaglandin from the separation of placenta results in closure of the ductus arteriosus.
What drug help close a Patent Ductus Ateriosus
Indomethacin
What drugs help to keep a PDA open
Prostaglandin E1 and E2
Name the remnant of the Foramen Ovale after its closure
Fossa Ovalis
Name the postnatal derivative of the allantois -> urachus
Median umbilical ligament
Urachus ( part of the allantoic duct between the bladder and umbilicus)
Name the postnatal derivative of the Ductus Arteriosus
Ligamentum Arteriosum
The Ligamentum Arteriosum is structurally close to
Left recurrent laryngeal nerve
Name the postnatal derivative of Ductus Venosus
Ligamentum venosum
Name the postnatal derivative of the Notochord
Nucleus Pulposus
Name the postnatal derivative of the Umbilical Arteries
Medial umbilical ligaments
