Mathematical analysis of tissue PO2 distribution in the cat carotid body.

The PO2 histogram of the carotid body tissue was calculated on the basis of a microscopical serial reconstruction, published physiological data, and a mathematical model. The calculation was made for glomoid as the subunit of the carotid body and the total organ by varying the following parameters: arterial PO2, oxygen consumption, hematocrit, diameter of the vessels, perfusion pressure, and capillary length. The results provide explanations for differences in the literature about the tissue PO2 distribution in the cat carotid body. Differences in the capillary length of the carotid bodies seem to be the main reason for different PO2 histograms. Furthermore, it is shown that the local flow velocities in the carotid body are in the range of local flow velocities known from other organs.