The pressure exerted against the walls of the artery when the left ventricle contracts is called the:

• A. Diastolic pressure
• B. Systolic pressure
• C. Mean arterial pressure
• D. Pulse pressure

Answer: (B)

The pressure against the arterial walls peaks when the heart contracts, pushing blood into the aorta. This peak is the systolic pressure. It reflects the force generated by the left ventricle during the upstroke of the heartbeat. In a typical reading like 120/80, 120 is the systolic value. The diastolic pressure, in contrast, is the pressure when the heart relaxes and fills, which is lower. Mean arterial pressure is a kind of average pressure in the arteries over the whole cycle, and pulse pressure is simply the difference between systolic and diastolic pressures.