RESUMO
A brief review of the accepted morphology of the liver relevant to hepatic haemodynamics is given, with a critical account of the methods previously used to study the parameters of hepatic circulation and of the results of such investigations. The theoretical basis of the method to be used in the experiments on the hepatic vascular bed is given. The conditions under which this theory is valid, in a real vascular system, are carefully examined. The method of preparing an isolated perfused canine liver and of recording indicator-dilution curves is described, emphasis being placed on practical considerations. Results of experiments on the pressure-flow relationships in the liver are presented to demonstrate the viability of the presentation. The concept of hepatic vascular 'spaces' and the method of their circulation from the indicator-dilution curves are described in detail. The results of the investigation into the variation of the hepatic vascular 'spaces' with flow rates are presented and the analysis of the variations in term of a regression line, are explained. On the basis of these results a three compartment model of the hepatic vascular system is proposed and the anatomical and theoretical significance of the model is examined. Further considerations of the model suggest certain lines of investigation:- (a) Functional differences between liver regions supplied by the portal vein and hepatic artery. (b) The effect of reversal of the venous circulation through the liver. Both these aspects are investigated and analysed in terms of the proposed model. The correspondence between the model and the accepted anatomy of the liver is examined. Finally the results are considered in comparision with those obtained by other methods and possible extensions of the present work are suggested (AU)
