Question

contraction of the papillary muscles would
multiple choice
prevent the av valves from protruding into the atria.
open the semilunar valves.
cause the atria to eject their contents into the ventricles.
ejct blood from the ventricles.
close the semilunar valves.

Explanation:

Papillary muscles are attached to the AV (atrioventricular) valves by chordae tendineae. When they contract, they prevent the AV - valves from prolapsing (protruding) into the atria during ventricular contraction. Opening and closing of semilunar valves are related to pressure differences in the heart, not papillary muscle contraction. Atrial ejection into ventricles is due to atrial contraction, not papillary muscle contraction. Ejection of blood from the ventricles is mainly due to ventricular contraction, not papillary muscle function.

Answer:

prevent the AV valves from protruding into the atria.