Answer:
The heart tendons play a role in atrial and ventrical systole, prevent prevent the eversion and prolapse.
Explanation:
Chordae tendineae (same as tendon of a heart):
The chordae tendineae, also known as the heartstrings, are cord like tendons that connect the papillary muscles to the tricuspid and bicuspid valves of the heart. The chordae tendineae play a role in atrial and ventrical systole. During atrial systole the chordae tendineae are relaxed because the atrioventricular valves are forced open. When the ventricles of the heart contract in ventricular systole, the increased blood pressures in both chambers push the AV valves to close simultaneously, preventing backflow of blood into the atria. Since the blood pressure in atria is much lower than that in the ventricles, the flaps attempt to evert to the low-pressure regions. The chordae tendineae prevent the eversion, prolapse, by becoming tense thus pulling the flaps, holding them in closed position.
https://pressbooks.bccampus.ca/advancedanatomy1sted/chapter/the-heart/