Heart sounds are the noises produced by the heart as it beats. These sounds are primarily caused by the closing of the heart valves, which include the mitral valve, tricuspid valve, aortic valve, and pulmonary valve. The two main heart sounds are known as "S1" and "S2." S1 occurs when the mitral and tricuspid valves close, while S2 happens when the aortic and pulmonary valves close. Healthcare professionals often use a stethoscope to listen to heart sounds during a physical examination. Abnormal heart sounds, such as "S3" and "S4," can indicate potential heart issues. These sounds provide valuable information about the heart's function and overall health, helping doctors diagnose conditions like heart murmurs or heart failure.