What are the papillary muscles?
The heart’s ventricles, the two bottom chambers, contain muscles known as papillary muscles.
The contraction of these papillaries during systole (rhythmic contraction of the ventricles) facilitates blood flow and prevents prolapse.
How many papillary muscles are there?
There are five papillary muscles, which attach to the heart’s atrioventricular valves.
Two of the muscles are located in the posterior and anterior walls of the left ventricle and connect to the two cusps of the bicuspid valve. The remaining three septal, posterior, and anterior muscles can be found in the walls of the right ventricle and connect to the three (or more) cusps of the tricuspid valve.
What is the function of the papillary muscles? How do they function?
The papillary muscles serve to shut the heart valves tightly and prevent prolapsing of the valve leaflets when the heart beats, keeping blood from flowing back into the atrial chambers.
The papillary muscles start to contract just before the ventricles contract, to prepare the valves for high ventricular pressure. They pull on the chordae tendinae or heart strings, maintaining tension until the ventricles relax in diastole. The valves then open and the next cardiac cycle begins.
What can go wrong with the heart’s papillary muscles?
Rupturing of the muscles. This can occur due to a heart attack (especially in the left ventricle) and is known as myocardial rupture, which is a emergency and requires urgent treatment.
In some cases, children are born with fewer or no papillary muscles, causing valve dysfunction. However, this is fairly rare. Ischemia can also cause papillary muscle dysfunction.