Contractions of the Papillary Muscles

Question

Contractions of the papillary muscles
A) close the atrioventricular valves.
B) close the semilunar valves.
C) eject blood from the ventricles.
D) prevent the atrioventricular valves from reversing into the atria.
E) eject blood from the atria into the ventricles.

Accepted Answer

The contraction of the papillary muscles occurs during ventricular contraction. They pull on the chordae tendineae, which are attached to the atrioventricular (AV) valves (mitral and tricuspid valves), preventing these valves from inverting or bulging back into the atria when the ventricles contract. This action ensures that blood flows in the correct direction - from the ventricles into the outflow tracts (towards the pulmonary artery and aorta) and not back into the atria.