CVS Practice Test 2026 – Complete Exam Preparation

The correct answer is that the statement is false because the contraction of the papillary muscles does not open the mitral and tricuspid valves; instead, it serves to prevent these valves from inverting into the atria during ventricular contraction (systole).

During ventricular systole, when the ventricles contract, the pressure increases and causes the mitral and tricuspid valves to close. The papillary muscles, which are attached to the valve leaflets by chordae tendineae, contract simultaneously with the ventricles. This contraction pulls on the chordae tendineae and keeps the valve leaflets in their proper position, preventing them from prolapsing (flipping back) into the atria. This mechanism is crucial for maintaining unidirectional blood flow and ensuring the valves function properly during the cardiac cycle.

In contrast to the claim about the valves opening, it is essential to note that the valves open passively when the pressure in the atria exceeds the pressure in the ventricles during diastole, not as a result of papillary muscle contraction. Thus, the understanding of the roles of the papillary muscles and the behavior of the heart valves is fundamental to comprehending cardiac physiology.