The human heart consists of four chambers: the left and right atria and the left and right ventricles. Each chamber plays a vital role in the circulation of blood throughout the body. The right atrium receives deoxygenated blood from the body and pumps it into the right ventricle, which then sends the blood to the lungs for oxygenation. The left atrium receives oxygenated blood from the lungs and passes it to the left ventricle, which pumps it out to the rest of the body. This efficient chamber design is crucial for maintaining effective circulation.