Which valve is located between the left atrium and left ventricle?

• A. Bicuspid (mitral) (L AV valve)
• B. Tricuspid (R AV valve)
• C. Pulmonary semilunar
• D. Aortic semilunar

Answer: (A)

The main idea here is identifying the valve that sits at the junction of the left atrium and left ventricle. That valve is the mitral valve, also called the bicuspid valve. It opens to let oxygenated blood flow from the left atrium into the left ventricle during diastole, and it tightens to prevent backflow when the left ventricle contracts. This valve is the left atrioventricular valve. The other valves are located at different junctions: the tricuspid valve sits between the right atrium and right ventricle, the pulmonary semilunar valve lies between the right ventricle and the pulmonary artery, and the aortic semilunar valve lies between the left ventricle and the aorta.