The valves between the atria and ventricles are collectively known as the

The valves between the atria and ventricles are collectively known as the

• A. AV valves
• B. Semilunar valves
• C. Chordsae tendineae
• D. Papillary muscles

Answer: (A)

Atrioventricular valves are the valves between the atria and ventricles. These include the mitral valve on the left and the tricuspid valve on the right. They open to let blood flow from the atria into the ventricles during filling, then close as the ventricles contract to prevent backflow into the atria. The leaflets are tethered by chordae tendineae to papillary muscles in the ventricles, which pull on the leaflets to prevent them from inverting into the atria when ventricular pressure rises. This system is different from the semilunar valves, which lie between the ventricles and the great arteries, and from the chordae tendineae and papillary muscles themselves, which support the AV valves rather than act as valves. The closing of the AV valves contributes to the first heart sound.

Atrioventricular valves are the valves between the atria and ventricles. These include the mitral valve on the left and the tricuspid valve on the right. They open to let blood flow from the atria into the ventricles during filling, then close as the ventricles contract to prevent backflow into the atria. The leaflets are tethered by chordae tendineae to papillary muscles in the ventricles, which pull on the leaflets to prevent them from inverting into the atria when ventricular pressure rises. This system is different from the semilunar valves, which lie between the ventricles and the great arteries, and from the chordae tendineae and papillary muscles themselves, which support the AV valves rather than act as valves. The closing of the AV valves contributes to the first heart sound.