How do the heart valves function?
As the heart muscle contracts and relaxes, the valves open and close, letting blood flow into the ventricles and out to the body at alternate times. The following is a step-by-step illustration of how the valves function normally in the left ventricle: • After the left ventricle contracts, the aortic valve closes and the mitral valve opens, to allow blood to flow from the left atrium into the left ventricle. • The left atrium contracts and more blood flows into the left ventricle. • When the left ventricle contracts, the mitral valve closes and the aortic valve opens, so blood flows into the aorta and the systemic circulation.
