How do papillary muscles and chordae tendineae function to keep the AV valves closed when the ventricles contract?

Papillary muscles and chordae tendineae work together to stabilize the atrioventricular (AV) valves during ventricular contraction. When the ventricles contract, they generate pressure that could force the AV valves upward, potentially leading to regurgitation. The papillary muscles, which are attached to the valve leaflets via the chordae tendineae, contract simultaneously to pull on these cords, keeping the valve leaflets securely closed and preventing backward flow of blood into the atria. This coordinated action ensures efficient blood ejection from the ventricles into the arteries.