SFOS 27

When does human heart begin to beat?

Week 4
What carries fetal blood to placenta?

Umbilical arteries
Ductus Venosus

Connects umbilical vein directly to IVC
Foramen Ovale

Opening in atrial septum to bypass pulmonary system
Ductus arteriosus
- Connects pulmonary artery to descending aorta
- To bypass pumonary system
Fetal compensation methods for decreased O2
- Increase umbilical venous resistance to improve exchange
- Increase of % flow across foramen ovale
- Redistribution to vital organs
Result of first breath
- Expansion of lung sharply drops pulmonary resistance
- Stimulates NO production (vasodilator)
- Closes ductus arteriosus, foramen ovale
Result of Right Heart Obstruction
- Hypoxemia after ductus arteriosus closure
- Limited flow to lungs from right ventricle
Note: tricuspid regurgitation, right atrial enlargement, foramen ovale enlargement
Hypoplastic left heart syndrome
- Left heart obstruction
- Fetal coronary perfusion via ductus arteriosus
- Upon closure, acidosis/death

Author

zf2010

80260

Card Set

SFOS 27

Description

SFOS 27

Updated

2011-04-18T01:54:04Z

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