Papillary muscle
Encyclopedia
In anatomy
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...

, the papillary muscles are muscles located in the ventricles of the heart. They attach to the cusps of the atrioventricular valves (a.k.a. the mitral
Mitral valve
The mitral valve is a dual-flap valve in the heart that lies between the left atrium and the left ventricle...

 and tricuspid
Tricuspid valve
The tricuspid valve, or right atrioventricular valve, is on the right dorsal side of the mammalian heart, between the right atrium and the right ventricle. The normal tricuspid valve usually has three leaflets and three papillary muscles. They are connected to the papillary muscles by the chordae...

 valves) via the chordae tendinae and contract to prevent inversion or prolapse of these valves.

Action

There are five total papillary muscles in the heart, three in the right ventricle and two in the left. The anterior, posterior, and septal papillary muscles of the right ventricle each attach via chordae tendineae
Chordae tendineae
The chordae tendineae, or heart strings, are cord-like tendons that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart....

 to the tricuspid valve
Tricuspid valve
The tricuspid valve, or right atrioventricular valve, is on the right dorsal side of the mammalian heart, between the right atrium and the right ventricle. The normal tricuspid valve usually has three leaflets and three papillary muscles. They are connected to the papillary muscles by the chordae...

. The anterior and posterior papillary muscles of the left ventricle attach via chordae tendineae
Chordae tendineae
The chordae tendineae, or heart strings, are cord-like tendons that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart....

 to the mitral valve
Mitral valve
The mitral valve is a dual-flap valve in the heart that lies between the left atrium and the left ventricle...

.

The papillary muscles of both the right and the left ventricles begin to contract shortly before ventricular systole and maintain tension throughout. This prevents regurgitation--backward flow of ventricular blood into the atrial cavities--by bracing the atrioventricular valves against prolapse--being forced back into the atria by the high pressure in the ventricles.

Rupture

Papillary muscle rupture, as can be caused by a heart infarct, and dysfunction, as can be caused by ischemia
Ischemia
In medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...

, can both lead to the complication of mitral valve prolapse
Mitral valve prolapse
Mitral valve prolapse is a valvular heart disease characterized by the displacement of an abnormally thickened mitral valve leaflet into the left atrium during systole. There are various types of MVP, broadly classified as classic and nonclassic. In its nonclassic form, MVP carries a low risk of...

.

External links

- "Heart: The Right Atrioventricular (Tricupsid) Valve" (anterior, posterior, septal papillary muscles) - "Heart: The Left Atrioventricular (Mitral) Valve" (anterior, posterior papillary muscles) - "Right atrioventricular bundle branch, anterior view"
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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