What is the difference between systolic and diastolic blood pressure?

What is the difference between systolic and diastolic blood pressure?

• A. Systolic is the pressure in arteries when the heart contracts; diastolic is the pressure when the heart relaxes between beats.
• B. Systolic is the heart rate.
• C. Diastolic is respiration rate.
• D. They are the same.

Answer: (A)

The main idea is that blood pressure has two values because it reflects two moments in the heart’s cycle. Systolic pressure is the higher value, representing arterial pressure when the heart contracts and ejects blood into the arteries. Diastolic pressure is the lower value, representing arterial pressure when the heart is relaxed between beats and the chambers fill with blood. A reading like 120/80 shows 120 as the peak during contraction and 80 as the pressure during relaxation. The other statements mix up what is being measured: heart rate is how many times the heart beats per minute, and respiration rate is how many breaths per minute, not the arterial pressures in different phases of the heartbeat. So, systolic = peak pressure during contraction, diastolic = trough pressure during relaxation.

The main idea is that blood pressure has two values because it reflects two moments in the heart’s cycle. Systolic pressure is the higher value, representing arterial pressure when the heart contracts and ejects blood into the arteries. Diastolic pressure is the lower value, representing arterial pressure when the heart is relaxed between beats and the chambers fill with blood. A reading like 120/80 shows 120 as the peak during contraction and 80 as the pressure during relaxation. The other statements mix up what is being measured: heart rate is how many times the heart beats per minute, and respiration rate is how many breaths per minute, not the arterial pressures in different phases of the heartbeat. So, systolic = peak pressure during contraction, diastolic = trough pressure during relaxation.