Mean circulatory pressure is (AIIMS NOV 2008)
|A||Average of pulmonary and circulatory pressure|
|B||Pressure at any 1 point when the heart is stopped|
|C||Average of central venous and systemic pressure|
|D||Diastolic BP + 1/3 pulse pressure|
I. Mean systemic filling pressureis slightly different from the mean circulatory filling pressure.
II. It is the pressure measured everywhere in the systemic circulation after blood flow has been stopped by clamping the large blood vessels at the heart, so that the pressure in the systemic circulation can be measured independently from those in the pulmonary circulation.
III. The mean systemic pressure, although almost impossible to measure in the living animal, is the important pressure for determining the venous return.
IV. The mean systemic filling pressure, however, is almost always nearly equal to the mean circulatory filling pressure because the pulmonary circulation has less than one eighth as much capacitance as the systemic circulation and only about one tenth as much blood volume.