Fetal circulation I
Blood returns from the placenta via the umbilical vein. Most is shunted through the liver to the inferior vena cava via the
ductus venosus. As it enters the right atrium, this relatively well-oxygenated blood is preferentially shunted through the foramen
ovale to the left atrium where it is mixed with a small amount of blood coming from the pulmonary veins. After this still relatively
well oxygenated blood is ejected into the aorta it supplies the heart and the brain as well as the upper extremities. Only a small
amount goes through the isthmus of the aorta into the descending aorta. (See the next slide for continuation of this text)
1 minute clinical correlation