The mitral valve uses flaps to prevent blood from flowing backward from the left ventricle to the left atrium of the heart between pumps. It is one of four valves in the heart that regulate the blood flow in the system.
Each time the heart pumps, the pressure of the blood flowing forces the flaps of the mitral valve open, allowing blood to flow from the left atrium to the left ventricle. When this pressure is released, the two flaps or leaflets of the valve close tightly against one another, preventing blood from flowing in the opposite direction.
The mitral valve works in conjunction with the other three heart valves to ensure that oxygenated and deoxygenated blood flow only in the correct directions, enabling the circulatory process to continue smoothly. The other three valves of the heart are the tricuspid, pulmonic and aortic valves.
Problems with the heart can arise if any of these valves becomes too stiff to open fully or close properly, as this impedes correct blood flow. Blood occasionally leaking back through valves that have not closed properly can be detected as a heart murmur, as in the case of a prolapse, but some more steady leaks or cases of mild regurgitations are symptom-free for years.