Mean arterial pressure is described as which of the following?

• A. The peak arterial pressure during systole.
• B. The minimum arterial pressure during diastole.
• C. The average pressure in the arteries during one heartbeat.
• D. The pressure forcing blood into tissues averaged over the cardiac cycle.

Answer: (D)

Mean arterial pressure is the average pressure that drives blood through the tissues over a cardiac cycle. It isn’t just the peak systolic pressure or the minimum diastolic pressure. The heart spends more time in diastole, so MAP is a cycle-weighted average that reflects the actual perfusion pressure reaching tissues. A common estimate is MAP ≈ diastolic pressure + one third of the pulse pressure (MAP ≈ DP + 1/3[SBP − DP]), which places it between systolic and diastolic pressures but weighted toward diastole. For example, with SBP 120 and DBP 80, MAP ≈ 80 + 1/3(40) ≈ 93 mmHg. This description—averaged over the cardiac cycle and representing the pressure driving tissue perfusion—best matches the concept.