Characteristics of Renal Vascular Resistance Changes Over the Autoregulatory Range in the Isolated Perfused Kidney.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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Six mongrel dogs were studied in experiments designed to determine the sites and magnitudes of renal vascular resistance changes over the autoregulatory range of arterial pressures in the isolated, perfused kidney. The experiments were designed around a lumped, two-resistor model of the total renal vascular resistance one component proximal to the site of interstitial fluid formation and one component distal to this point. The results of this study demonstrated that 1 a large percentage of the total renal vascular resistance is proximal to the site of interstitial fluid formation and, 2 that this pre-venous resistance component is the most sensitive to changing renal artery pressures and is therefore the major contributor to the observed regulation of renal blood flow. In view of these findings and the fact that relatively low interstitial pressures 5-40 mmHg. were recorded, it is suggested that an active mechanism -- either system is the cause of the observed blood flow regulation. A proposed model based on this and other studies and featuring a breakdown of the pre-venous segmental resistance component is presented. The set of equations defining the models performance are derived and an experimental procedure to obtain the parameters which are necessary to solve the system equations is outlined. Author
- Anatomy and Physiology