Diastole is the period of:

Diastole is the period of:

• A. Ventricular contraction
• B. Ventricular relaxation
• C. Atrial contraction
• D. Valve closure

Answer: (B)

Diastole is the relaxation phase of the ventricles in the cardiac cycle. After the ventricles have contracted and ejected blood, they relax to allow filling. During this time, ventricular pressure falls below atrial pressure, so the mitral and tricuspid valves open and blood moves from the atria into the ventricles. The semilunar valves (aortic and pulmonary) remain closed, preventing backflow into the arteries. A key part of diastole is the late phase when the atria contract to top off ventricular filling, but the defining idea is the ventricular relaxation itself. This phase corresponds to the diastolic reading in blood pressure, reflecting arterial pressure when the heart is relaxed between beats.

Diastole is the relaxation phase of the ventricles in the cardiac cycle. After the ventricles have contracted and ejected blood, they relax to allow filling. During this time, ventricular pressure falls below atrial pressure, so the mitral and tricuspid valves open and blood moves from the atria into the ventricles. The semilunar valves (aortic and pulmonary) remain closed, preventing backflow into the arteries. A key part of diastole is the late phase when the atria contract to top off ventricular filling, but the defining idea is the ventricular relaxation itself. This phase corresponds to the diastolic reading in blood pressure, reflecting arterial pressure when the heart is relaxed between beats.