Which statement accurately differentiates systolic blood pressure from diastolic blood pressure?

Which statement accurately differentiates systolic blood pressure from diastolic blood pressure?

• A. Systolic is pressure during heart contraction; diastolic is pressure during relaxation
• B. Diastolic pressure occurs during heart contraction; systolic is pressure during relaxation
• C. Systolic and diastolic refer to blood glucose levels
• D. Diastolic pressure occurs only at night

Answer: (A)

The main idea is that systolic and diastolic pressures describe arterial pressure at different phases of the heartbeat. Systolic pressure is the pressure in the arteries when the heart contracts (systole) and pushes blood out into the circulation, reaching the peak arterial pressure. Diastolic pressure is the pressure in the arteries when the heart is relaxing (diastole) and filling with blood, representing the lowest arterial pressure between beats. That’s why blood pressure is read as a ratio like 120/80, with the first number reflecting the peak during contraction and the second reflecting the baseline pressure during relaxation. This distinction is clinically meaningful because each phase can be affected differently by factors like arterial stiffness or vascular resistance. The other statements would mix up the phases or refer to unrelated concepts, so they don’t fit the physiological definitions.

The main idea is that systolic and diastolic pressures describe arterial pressure at different phases of the heartbeat. Systolic pressure is the pressure in the arteries when the heart contracts (systole) and pushes blood out into the circulation, reaching the peak arterial pressure. Diastolic pressure is the pressure in the arteries when the heart is relaxing (diastole) and filling with blood, representing the lowest arterial pressure between beats. That’s why blood pressure is read as a ratio like 120/80, with the first number reflecting the peak during contraction and the second reflecting the baseline pressure during relaxation. This distinction is clinically meaningful because each phase can be affected differently by factors like arterial stiffness or vascular resistance. The other statements would mix up the phases or refer to unrelated concepts, so they don’t fit the physiological definitions.