The Path through the Heart

Christopher writes to ask: What path is the blood in the heart?

Oxygen poor blood from the body enters the right atrium of the heart. From there it flows into the right ventricle. From the right ventricle, the blood is pumped to the lungs where it becomes oxygenated. From the lungs, the blood is returned to the left atrium of the heart, and flows to the left ventricle, from which it is then pumped out into the body again.

Nova has a very nice animated illustration of this process here.

Summer