What is the role of papillary muscles during heart contraction?

What is the role of papillary muscles during heart contraction?

• A. They contract to anchor the chordae tendineae of the AV valves, preventing backflow into the atria
• B. They pump blood into the ventricles
• C. They regulate heart rate by signaling the AV node
• D. They open the mitral and tricuspid valves

Answer: (A)

Papillary muscles work with the chordae tendineae to keep the AV valve leaflets from flipping back into the atria during ventricular contraction. When the ventricles contract, the papillary muscles also pull on the chordae, tensing them so the mitral and tricuspid valve cusps stay closed and don’t bulge upward. This prevents backflow into the atria and helps maintain one-way flow from the ventricles to the outflow vessels. They don’t pump blood themselves, nor do they regulate heart rate or signal the AV node, and they don’t open the valves—valves open passively to allow ventricular filling during diastole and close during systole due to pressure changes and the tethering prevents prolapse.

Papillary muscles work with the chordae tendineae to keep the AV valve leaflets from flipping back into the atria during ventricular contraction. When the ventricles contract, the papillary muscles also pull on the chordae, tensing them so the mitral and tricuspid valve cusps stay closed and don’t bulge upward. This prevents backflow into the atria and helps maintain one-way flow from the ventricles to the outflow vessels.

They don’t pump blood themselves, nor do they regulate heart rate or signal the AV node, and they don’t open the valves—valves open passively to allow ventricular filling during diastole and close during systole due to pressure changes and the tethering prevents prolapse.