Flashcards in Autoregulation and embryology Deck (18):
draw the picture for heart derivatives
see FA pg 263
What defect leads to dextrocardia?
defect in dynein (Kartagener syndrome: primary ciliary dyskinesia)
draw a picture for separation of the atria
see FA pg 262
What is the most common location for a VSD? How do they look at birth?
acynotic at birth becasue of left-to-right shunt.
often develops in the membranous septum
From what do the aortic and pulmonary valves arise?
from the endocardial cushions of the outflow tract
From what do mitiral and tricuspid tracts arise?
fused endocardial cushions of the AV canal
Where does fetal erythropoeisis occur?
yolk sac: 3-8 wks
liver 6 wks-birth
spleen: 10-28 wks
bone marrow: 18 wks-adult
(young liver synthesizes blood)
What is the composition of adult hemoglobin? fetal hemoglobin?
adult hemoglobin is a2beta2
alpha always, gamma goes, becomes beta.
What is 2,3-BPG?
molecule that changes the affinity of Hb for oxygen. It binds to best to deoxygenated hemoglobin (like near a respiring tissue). It works to decrease the affinity of the other hemoglobin molecules for oxygen to promote O2 release from RBCs to the tissue.
When 2,3 BPG is low, hemoglobin as a higher affinity for oxygen.
Summary: 2,3-BPG causes decreased Hb affinity for O2 and increased delivery to tissues.
What are the differences in fetal vs. adult hemoglobin?
HbF has a higher affinity for O2 because of less avid binding of 2,3-BPG. this allows HbF to extract oxygen from maternal Hb across the placenta.
What are the 3 important shunts in the fetal circulation?
1. blood from the placenta goes to the liver, where it is shunted through the ductus venosus to the IVC. this bypasses the hepatic circulation.
2. blood is shunted through the foramen ovale from the RA to the LA.
3. blood from the right ventricle is shunted away from the lungs due to high pulmonary pressures and into the aorta via the
What helps close a PDA? What helps keep one open?
indomethacine closes a PDA. naturally, increasing O2 from respirations helps close the PDA
What keep PDAs open
prostaglandins E1 and E2
ligamentum teres hepatis in the falciform ligament
mediaL umbilical ligaments