papillærmuskler

Papillärmuskler are small, cone-shaped muscles located in the ventricles of the heart. There are typically three papillärmuskler in the left ventricle and four in the right ventricle. These muscles are attached to the chordae tendineae, which are strong, fibrous cords that, in turn, are connected to the cusps of the mitral valve (in the left ventricle) and the tricuspid valve (in the right ventricle).

The primary function of the papillärmuskler is to control the opening and closing of the atrioventricular valves. During ventricular contraction (systole), the pressure within the ventricles rises, which would normally cause the valve cusps to bulge backward into the atria, allowing blood to leak. However, the papillärmuskler contract simultaneously with the ventricles. This contraction pulls on the chordae tendineae, which then hold the valve cusps taut, preventing them from prolapsing and ensuring that the valves close properly to prevent backflow of blood.

During ventricular relaxation (diastole), the papillärmuskler relax, allowing the chordae tendineae to slacken and the atrioventricular valves to open, permitting blood to flow from the atria into the ventricles. Dysfunction of the papillärmuskler, often due to damage from a heart attack, can lead to impaired valve function and potentially serious complications such as mitral regurgitation or tricuspid regurgitation.