Heart physiology

The heart is a muscular organ that pumps blood throughout the body. It has four chambers: two upper atria and two lower ventricles. Blood low in oxygen from the body enters the right atrium, moves to the right ventricle, and is then pumped to the lungs to receive oxygen. Oxygen-rich blood returns to the left atrium, flows into the left ventricle, and is then pumped out through the aorta to supply oxygen and nutrients to tissues. The heart's rhythmic contractions (heartbeat) coordinate to maintain continuous blood flow, ensuring organs and tissues receive the oxygen and nutrients they need to function properly.