Which statement best defines mean arterial pressure (MAP)?

Which statement best defines mean arterial pressure (MAP)?

• A. The pressure in the arteries during peak systole
• B. The pressure forcing blood into tissues, averaged over the cardiac cycle
• C. The venous pressure returning to the heart
• D. The mean pressure in the pulmonary circulation

Answer: (B)

Mean arterial pressure represents the average pressure in the arterial system over an entire cardiac cycle, and it’s the pressure that drives blood through the tissues. Because diastole lasts longer than systole, MAP sits closer to the diastolic pressure. A handy approximation is diastolic pressure plus one third of the pulse pressure (systolic minus diastolic). MAP also roughly equals cardiac output multiplied by systemic vascular resistance in a steady state. This isn’t the peak systolic pressure, nor venous pressure returning to the heart, nor the mean pressure in the pulmonary circulation.

Mean arterial pressure represents the average pressure in the arterial system over an entire cardiac cycle, and it’s the pressure that drives blood through the tissues. Because diastole lasts longer than systole, MAP sits closer to the diastolic pressure. A handy approximation is diastolic pressure plus one third of the pulse pressure (systolic minus diastolic). MAP also roughly equals cardiac output multiplied by systemic vascular resistance in a steady state. This isn’t the peak systolic pressure, nor venous pressure returning to the heart, nor the mean pressure in the pulmonary circulation.