Question

which of the following are attached to papillary muscles by chordae tendineae and control the opening and closing of the valves?

atrioventricular valves

atria

ventricles

semilunar valves

Explanation:

To solve this, we recall the anatomy of the heart: Atrioventricular (AV) valves (mitral and tricuspid) are attached to papillary muscles via chordae tendineae. These structures prevent the AV valves from prolapsing into the atria during ventricular contraction, controlling valve opening/closing. Atria are upper heart chambers, ventricles are lower chambers, and semilunar valves (aortic, pulmonary) have no chordae tendineae or papillary muscle attachments.

Answer:

A. Atrioventricular valves