What two structures aid the atrioventricular valves in preventing backflow?

What two structures aid the atrioventricular valves in preventing backflow?

• A. Chordae tendineae and papillary muscles
• B. Aortic and pulmonary semilunar valves
• C. Interventricular septum and trabeculae carneae
• D. Bicuspid and tricuspid valves

Answer: (A)

When the ventricles squeeze, the heart needs the atrioventricular valves to stay closed so blood doesn’t flow back into the atria. The key supporters are the chordae tendineae and the papillary muscles. The chordae are string-like attachments to the leaflets of the AV valves, and the papillary muscles anchor into the ventricular walls. As the ventricle contracts, the papillary muscles pull on the chordae, tensing the leaflets and preventing them from bulging backward (prolapsing) into the atria. This coordination keeps one-way blood flow from the atria into the ventricles during systole and prevents regurgitation. The other structures listed don’t play this specific role: the semilunar valves are for the outflow tracts, the ventricular septum and trabeculae carneae are internal ventricular structures, and the valves themselves are the AV valves, not their support.

When the ventricles squeeze, the heart needs the atrioventricular valves to stay closed so blood doesn’t flow back into the atria. The key supporters are the chordae tendineae and the papillary muscles. The chordae are string-like attachments to the leaflets of the AV valves, and the papillary muscles anchor into the ventricular walls. As the ventricle contracts, the papillary muscles pull on the chordae, tensing the leaflets and preventing them from bulging backward (prolapsing) into the atria. This coordination keeps one-way blood flow from the atria into the ventricles during systole and prevents regurgitation. The other structures listed don’t play this specific role: the semilunar valves are for the outflow tracts, the ventricular septum and trabeculae carneae are internal ventricular structures, and the valves themselves are the AV valves, not their support.