What are the atrioventricular (AV) valves?

• A. Valves lie between ventricles and great arteries
• B. Valves lie between the atria and ventricles
• C. Valves within the aorta
• D. Valves between the ventricles and the atrial septum

Answer: (B)

The main idea is where the heart valves are located and what they do. The atrioventricular valves sit between the atria and the ventricles, with the mitral valve on the left and the tricuspid valve on the right. They open during diastole to let blood flow from the atria into the ventricles and close during systole to prevent blood from flowing backward into the atria. They’re supported by chordae tendineae attached to papillary muscles to keep them from prolapsing when the ventricles contract. In contrast, valves between the ventricles and the great arteries are the semilunar valves (aortic and pulmonary), which handle blood ejection from the heart. There isn’t a valve between the ventricles and the atrial septum under normal anatomy.