Which valve separates the left atrium and left ventricle?

• A. Aortic valve
• B. Mitral valve
• C. Tricuspid valve
• D. Pulmonary valve

Answer: (B)

Think about the path blood takes from the left atrium into the left ventricle. The valve there is the mitral valve, also called the bicuspid valve. It’s an atrioventricular valve located between the left atrium and left ventricle. It opens to allow blood to flow from the atrium to the ventricle during diastole when atrial pressure is higher, and it closes as the ventricle contracts during systole to prevent backflow into the atrium. The other valves sit at different outflow or junctions: the aortic valve sits between the left ventricle and the aorta, the pulmonary valve between the right ventricle and the pulmonary artery, and the tricuspid valve between the right atrium and right ventricle. So, the valve separating the left atrium and left ventricle is the mitral valve.