What heart valve prevents backflow from the right ventricle to the right atrium?

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

Answer: (A)

The valve that sits between the right atrium and the right ventricle is the tricuspid valve. It prevents backflow from the right ventricle into the right atrium when the ventricle contracts. During diastole, the valve is open to let blood move from the atrium into the ventricle; during systole, the increased pressure in the ventricle closes the valve so blood can’t flow backward. The structure is anchored by chordae tendineae to papillary muscles, which helps keep the cusps from flipping into the atrium.

The other valves have different roles: the mitral valve sits between the left atrium and left ventricle, the aortic valve controls flow from the left ventricle to the aorta, and the pulmonary valve controls flow from the right ventricle to the pulmonary artery. None of these regulate backflow into the right atrium.