Blood Pressure and Mean Arterial Pressure
Blood pressure (BP) or "arterial blood pressure" is the pressure exerted by circulating blood upon the walls of blood vessels.
It is one of the principal vital signs.
During each heartbeat, blood pressure varies between a maximum (systolic) and a minimum (diastolic) pressure.
The blood pressure in the circulation is principally due to the pumping action of the heart. (1)
Differences in mean blood pressure are responsible for blood flow from one location to another in the circulation. The rate of mean blood flow depends on the resistance to flow presented by the blood vessels.
Mean blood pressure decreases as the circulating blood moves away from the heart through arteries and capillaries due to viscous losses of energy.