Michaelis-Menten-Like Kinetics in the Krogh Tissue Cylinder
In 1978, Schubert, Whalen, and Nair published the results of a series of experiments involving a Krebs-Henseleit perfused, paced, isovolumic working cat heart. The stated primary purpose of their work was to estimate the distribution of tissue PO2 in the autoregu-lating heart at two levels of perfusion pressure. They also measured flow, oxygen consumption, oxygen extraction, and left ventricular function (peak left ventricular pressure and its derivative). Their results indicated that the distribution of tissue PO2 is under a fine degree of control. The only interval in the tissue PO2 histogram to show a highly significant difference for a change in perfusion pressure was the 0–5 mmHg range. It was also discovered that the autoregulating group exhibited good regulation of flow, oxygen extraction, oxygen consumption, and left ventricular function. Futhermore, their results suggested that oxygen is being shunted around the capillary bed, possibly by both a diffusive shunt and a convective shunt.
KeywordsPerfusion Pressure Capillary Density Axial Diffusion Maximum Consumption Tissue Cylinder
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