Embryonic heart (Congenital HD, heart disease)
- Lungs are collapsed in human fetus
- 2 passageways in embryonic heart permit blood flow to bypass the lungs
- -Foramen ovale: Flow is RA -> LA (blood bypasses pulmonary circulation and no O2!)
- -Ductus Arteriosus: Connects pulmonary artery and aorta; Flow is Pulm art -> Aorta (can cause no symptoms or heart murmur, etc.)
- *Foramen and ductus usually close shortly after birth.