Which muscles of the heart are responsible for contracting and tightening the chordae tendinea?

The papillary muscles are responsible for contracting and tightening the chordae tendineae in the heart. These muscles are located in the ventricles and are attached to the valve leaflets via the chordae tendineae, which are fibrous cords that help anchor the heart valves.

When the ventricles contract during systole, the papillary muscles also contract. This contraction pulls on the chordae tendineae, preventing the atrioventricular (AV) valves (the mitral and tricuspid valves) from inverting into the atria. This mechanism is crucial for maintaining proper blood flow and preventing backflow into the atria, ensuring the heart functions effectively.

Other muscle groups, such as the ventricular and atrial muscles, play important roles in the overall contraction and pumping action of the heart, but they do not directly engage with the chordae tendineae. The coronary muscles are not a recognized group in the context of heart anatomy and function; thus, they are not relevant to the question regarding the function of the chordae tendineae.