Which valve prevents backflow from the left ventricle into the left atrium during ventricular contraction?

Which valve prevents backflow from the left ventricle into the left atrium during ventricular contraction?

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

Answer: (B)

The mitral valve prevents backflow from the left ventricle into the left atrium during ventricular contraction. It sits between the left atrium and left ventricle and closes as the ventricle’s pressure rises in systole, stopping blood from regurgitating back into the atrium. This timing also allows blood to be ejected into the aorta once the aortic valve opens. The aortic semilunar valve and pulmonary semilunar valve control flow into the great arteries and pulmonary artery, not back into the atria, and the tricuspid valve is on the right side of the heart between the right atrium and right ventricle.

The mitral valve prevents backflow from the left ventricle into the left atrium during ventricular contraction. It sits between the left atrium and left ventricle and closes as the ventricle’s pressure rises in systole, stopping blood from regurgitating back into the atrium. This timing also allows blood to be ejected into the aorta once the aortic valve opens. The aortic semilunar valve and pulmonary semilunar valve control flow into the great arteries and pulmonary artery, not back into the atria, and the tricuspid valve is on the right side of the heart between the right atrium and right ventricle.