Answer: They prevent the cusps of the tricuspid and mitral valves from swinging into the atria when the ventricles contract.
Explanation:
The chordae tendineae are a group of tendinous and tough strands found in the heart and referred to as the “heart strings” because they resemble small pieces of string. They play a vital role in holding the atrioventricular valves in place while the heart pumps blood. They also connect to the papillary muscles which are muscles located in the ventricles of the heart and they attach to the cusps of the atrioventricular valves (also known as the mitral and tricuspid valves). They pull the chordae tendineae taut during ventricular contraction, which prevents prolapse of the atrioventricular valves into the atria. This means they prevent inversion or prolapse of these valves on systole.
So they both prevent the cusps of the tricuspid and mitral bicuspid valves from swinging into the atria during ventricular contraction. The thinner wall of the right ventricle creates the lower pressure needed to move blood a relatively short distance to the lungs (pulmonary circuit).
