What are the four chambers of the heart and what do they do?

The four chambers are called the right atrium, the left atrium, the right ventricle and the left ventricle. Deoxygenated blood enters the right atrium and is pumped into the right ventricle. The blood is then pumped from here to the lungs, where it becomes oxygenated. The blood then returns to the heart to the left atrium. It is pumped into the left ventricle. From here it is pumped to the rest of the body, before returning to the right atrium and starting the cycle again.