PHYSIOLOGICAL SIGNIFICANCE OF CARDIOVASCULAR DYNAMICS

The arterial tree can be described in terms of peripheral resistance a nd total arterial compliance, The product of these two is the time con stant of the arterial system and this time constant describes the deca y of aortic pressure in diastole, The pump function graph is a charact erization of the heart as a pump in terms of pressure and flow, Later it was found that in the intact animal cardiac power output was maxima l for the pressure and flow in the control situation (the working poin t), The ratio of heart period (R-R interval) and arterial time constan t is the same in mammals, Since mean pressure at the level of the brai n is similar in mammals, it implies that diastolic aortic pressure and also systolic pressure are similar, irrespective of the differences i n their body size and heart rate, It can be shown that the time consta nt of the arterial system and thus also the heart period is proportion al to body length, Cardiac output is determined by body mass and mean pressure is the same in mammals, This implies that the normal working- point on the pump function graph is given. Through this working point many pump function graphs can be drawn, It could be shown that total v entricular volume, i.e., lumen plus wall volume, is minimal when the w orking point is found at optimal power output.