In order to investigate the effects of arterial beds on pressure waveforms in arteries, the pressure waves observed in the rat tail artery were resolved into their Fourier moduli before and during ligation of the left renal artery and the superior mesenteric artery. Consistently different patterns of waveform changes in the tail artery were seen on occlusion of these vessels. Ligation of the renal artery reduced, and of the superior mesenteric artery increased, the pressure harmonics over most of the spectra. These results imply that to study the changes in the pressure contours as the observation point is moved downstream, one may have to account separately for the contributions of individual arterial beds. This is relevant in considering the degree to which it is appropriate for data to be amalgamated in models of the systemic arterial bed.

Like electrical circuit components, the vascular beds in organs present impedance to waves in systemic circulation. In this study, the authors design an animal experiment to study the effect of the impedance to the pressure waves. We view the systemic circulation as an electrical circuit network, and interpret the vascular beds in organs as lumped components in the electrical circuit. Nature's designing of the systemic circulation minimizes the pressure wave reflection, and maximizes blood distribution. This is very similar to the concept adopted by electrical engineers in designing electrical circuits. 'Ci