Abstract:
It has been recognised for a long time that the vas-cular system consists largely of a complex configuration of branched elastic tubes. According to Poioeuille's law, the flux of a viscous incompressible fluid through a rigid tube is a linear function of the pressure difference between the ends of the tube.. However, in the vascular beds of mammals, the pressure flow relation is always non-linear. This non-linearity has been ascribed to the elastic nature of blood vessels and their consequent rather large disten-sibility.
A great variety of mathematical and physical models of the human arterial system has been introduced, since the start of investigation in this field. They can basically be divided in two groups: the 'Windkessel-models' and the 'Transmission models.'. It is generally felt now-a-days that a modelshould be more sophisticated and should have counter... parts of the essential hemo-dynamic quantities in the actual system such as pressure-flow relationships, reflection coeff-icients, pulse wave velocity etc. The 'Windkessel' models can not be expected to do this because they lack in their original concept, a representation of pulse wave velocity. The Windkessel
is equivalent to a single chamber, that is, a lumped system, in which the wave velocity is infinite and pressure and flow pulses change simultaneously.
