Heart valve

In anatomy, the heart valves are valves in the heart that prevent blood from flowing the wrong way.

There are four valves of the heart:

• Two AV valves - ensure blood flows from the atria to the ventricles, and not the other way.
• Two semilunar valves - these are present in the arteries leaving the heart, and they prevent blood flowing back from the artery into the ventricle.

Heart valves open and shut depending on the difference in pressure on each side. The sound of the heart valves shutting causes the heart sounds.

AV valves

These are large, multicusped valves that prevent backflow from the ventricles into the atria during systole. They are anchored to the wall of the ventricle by chordae tendinae, that prevent the valve from inverting.

The chordae teninae are attached to papillary muscles that cause tension to better hold the valve. They have no effect on the opening at shutting though. This is caused entirely by a pressure difference on each side of the valve.

Mitral valve

Also known as the bicuspid valve, the mitral valve gets its name from the resemblance to a bishop's mitre (a type of hat).

Tricuspid valve

On the right side of the heart.

Semilunar valves

These are positioned on the pulmonary artery and the aorta.

Pathology of the valves

• Endocarditis
• Stenosis
• et cetera

Artificial heart valves

This deserves an article of its own: Artificial heart valve.