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.

Table of contents 1 AV valves 1.1 Mitral valve 1.2 Tricuspid valve 2 Semilunar valves 2.1 Aortic valve 2.2 Pulmonary valve 3 Pathology of the valves 4 Artificial heart valves

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). It prevents blood flowing from the left ventricle into the left atrium. As it is on the left side of the heart, in must cope with a lot of strain and pressure, this is while it is madeof only two cusps, as there is less to go wrong.

Tricuspid valve

It is on the right side of the heart, and prevents flow from the right ventricle to the right atrium. Being the first valve after the venae cavae, and thus the whole venous system, it is the most common valve to be infected (endocarditis) in IV drug[?] users.

Semilunar valves These are positioned on the pulmonary artery[?] and the aorta. This valves to not have chordae tendinae, but are more similar to valves in veins.

Aortic valve

Stops blood coming back from the aorta into the left ventricle during diastole[?].

Pulmonary valve

Prevents blood flow back from the pulmonary trunk[?] to the right ventricle.

Pathology of the valves

• Endocarditis
• Stenosis - a constricture of the heart valve, making it hard for blood to get through.
• Insufficiency - the inability of the heart valve to close properly, meaning some blood can flow the wrong way.
• et cetera

Artificial heart valves This deserves an article of its own: Artificial heart valve[?].