Question

Diagram the flow of blood through a fetal heart, starting at the right atrium and ending at the descending aorta. Identify the structures and blood vessels through which the blood flows; identify blood vessels as arteries or veins.

Answer 1

Blood enters the right atrium, the chamber on the upper right side of the heart. When the blood enters the right atrium, most of it flows through the foramen ovale into the left atrium. Blood then passes into the left ventricle (lower chamber of the heart) and then to the aorta, (the large artery coming from the heart). From the aorta, blood is sent to the heart muscle itself in addition to the brain and arms. After circulating there, the blood returns to the right atrium of the heart through the superior vena cava. Very little of this less oxygenated blood mixes with the oxygenated blood and, instead of going back through the foramen ovale, goes into the right ventricle. This less oxygenated blood is pumped from the right ventricle into the aorta. A small amount of the blood continues on to the lungs. Most of this blood is shunted through the ductus arteriosus to the descending aorta. This blood then enters the umbilical arteries and flows into the placenta. In the placenta, carbon dioxide and waste products are released into the mother's circulatory system, and oxygen and nutrients from the mother's blood are released into the fetus' blood.