Which statement correctly defines systolic and diastolic blood pressure?

• A. Systolic pressure occurs during ventricular relaxation; diastolic during contraction
• B. Systolic pressure is the lowest arterial pressure during the cardiac cycle
• C. Systolic pressure is the average arterial pressure during the cycle
• D. Systolic pressure is the peak arterial pressure during ventricular contraction; diastolic pressure is the pressure during relaxation

Answer: (D)

Arterial pressure rises to a peak when the ventricles contract and eject blood into the aorta, then falls during the heart’s relaxation as the ventricles fill. That peak is systolic pressure—the pressure in the arteries during ventricular contraction. The pressure during relaxation is diastolic pressure—the arterial pressure while the heart muscle is resting between beats. This is why the correct statement describes systolic as the peak during contraction and diastolic as the pressure during relaxation. The other options mix up contraction versus relaxation or incorrectly define systolic as the lowest or an average pressure.