1. Fetal Blood Circulation

2. Fetal and adult differences
Fetal lungs- collapsed and non functional
Digestive tract has nothing to digest
Some blood travels to liver and lungs for growth and development, but not for functional purposes
All nutritional and respiratory needs occur through diffusion across a placenta- layer of tissue in close contact with the wall of the uterus.

3. Blood supply single umbilical vein- brings nutrients to fetus
Attached directly to Vena Cava through ductos venous (not present in adults)
a pair of umbilical arteries- branches off the ascending aorta and internal iliac veins in the legs.
Returns blood to placenta

5. Circulation in the heart
The foramen ovale is a small flap of tissue that allows blood to pass from the right atria to the left atria- bypassing the lungs.
A second passage way- ductos arteriosis connects the right ventricle and pulmonary artery to the aorta- bypassing the lungs.

7. Changes at Birth First breath- lungs expand
Pressure causes foramen ovale to close
Immediate vasoconstriction causes closure of Ductos arteriosis forms ligament (arterial ligament)
Surgical procedures may be necessary to fix problems