A heart valve is a structure in the heart that helps control the flow of blood. There are four main valves: the mitral valve, tricuspid valve, aortic valve, and pulmonary valve. Each valve opens and closes at specific times during the heartbeat, ensuring that blood moves in the right direction and preventing backflow. Heart valves are made of flexible tissue and are essential for maintaining proper circulation. When valves do not function correctly, it can lead to conditions such as valvular heart disease, which may require medical intervention. Proper heart valve function is crucial for overall cardiovascular health.