The human heart has four chambers: the right atrium, right ventricle, left atrium, and left ventricle. These chambers serve distinct functions in the heart's role as a pump, circulating blood through the body. The right atrium receives deoxygenated blood from the body, sending it to the right ventricle, which pumps it to the lungs for oxygenation. The left atrium receives oxygen-rich blood from the lungs, delivering it to the left ventricle, which then pumps it throughout the body, ensuring efficient circulation and overall health.