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RESEARCH PRODUCT

Mathematical Modelling of Local Regulation of Blood Flow by Veno-Arterial Diffusion of Vasoactive Metabolites

subject

description

It is widely accepted that vasoactive substances which are consumed or produced by tissue metabolism play a role in the adjustment of local perfusion rate to the metabolic needs of the tissue. In order to evoke a response of the vascular system, these substances — in the following for simplicity denoted by “vasodilators” even though oxygen, for example, is a vasoconstrictor — need to get into close contact with the small arterioles which represent the most powerful effectors in perfusion control. On the other hand, tissue sites in which supply with nutrients is most critical (“lethal corners”) and in which a vasodilator signal may be generated earliest, are located hundreds of µm away from the arteriolar supply. In an attempt to explain how this gap in the signal chain may be bridged, it has been suggested that vasodilators released by the tissue cells are taken up by the blood stream and transported with the blood to the venules and from there by diffusion to the accompanying arterioles which are reactive to changes in vasodilator concentration [9, 16].