Which valve prevents backflow from the left ventricle into the left atrium?

Which valve prevents backflow from the left ventricle into the left atrium?

• A. Bicuspid Valve
• B. Semilunar Valve
• C. Movement of blood
• D. Cardiac Conduction System

Answer: (A)

The key idea is how heart valves prevent backflow to maintain one-way blood flow. Between the left atrium and left ventricle sits the bicuspid (mitral) valve. It opens to let blood move from the atrium into the ventricle when the ventricle is filling, and it closes as the ventricle contracts. This closure stops blood from squirting back into the atrium during ventricular systole, keeping the circulation efficient on the left side of the heart. The semilunar valve is the valve between the left ventricle and the aorta, which prevents backflow from the aorta into the ventricle, not into the atrium. The remaining options describe movement of blood or the cardiac conduction system, neither of which are valves. So the bicuspid (mitral) valve is the correct choice.

The key idea is how heart valves prevent backflow to maintain one-way blood flow. Between the left atrium and left ventricle sits the bicuspid (mitral) valve. It opens to let blood move from the atrium into the ventricle when the ventricle is filling, and it closes as the ventricle contracts. This closure stops blood from squirting back into the atrium during ventricular systole, keeping the circulation efficient on the left side of the heart. The semilunar valve is the valve between the left ventricle and the aorta, which prevents backflow from the aorta into the ventricle, not into the atrium. The remaining options describe movement of blood or the cardiac conduction system, neither of which are valves. So the bicuspid (mitral) valve is the correct choice.