Which chamber pumps deoxygenated blood to the lungs under low pressure?

• A. Systolic pressure
• B. Diastolic pressure
• C. Pulse pressure
• D. Mean arterial pressure

Answer: (B)

This question is testing how pressure in the heart cycle relates to sending blood to the lungs. The pulmonary circuit operates under lower pressure than the systemic circuit, so the stage of the cycle that reflects a lower, resting pressure is most relevant here. The right ventricle does push deoxygenated blood into the lungs, and because the lungs are a low-resistance path, the pressures involved are comparatively low.

Diastolic pressure is the arterial pressure during the heart’s relaxation and filling phase, the lowest pressure reached in the cycle. That low-pressure state mirrors the pulmonary circulation’s low-pressure environment, which is why this term best fits the idea of pumping to the lungs under low pressure.

Systolic pressure is the peak pressure during contraction, which is the opposite of a low-pressure condition. Pulse pressure is the difference between systolic and diastolic pressures, not a pressure phase itself. Mean arterial pressure is an average that blends the two phases and doesn’t specifically describe the low-pressure moment.