General

The circulatory system

If we follow a single drop of blood through the body, we see that it first absorbs oxygen in the lungs (during the pulmonary circulation). It then travels through the heart, the aorta and the arteries to the organs of the body. The blood releases its oxygen there and absorbs carbon dioxide.

After passing through the organs, the blood flows back to the heart through the veins. The blood then re-enters the pulmonary circulation in order to deliver carbon dioxide to the lungs and to reabsorb oxygen. This process repeats itself as long as you live.