Concentration profiles in and around capillaries

Abstract
Capillaries, idealized as uniform cylinders through which blood flows at a constant velocity, supply substrate to the surrounding tissue, where it is consumed according to zero order or first order kinetics. Equations are developed which permit the calculation of the steady state concentration of substrate at any point inside the capillary or the tissue. The effects of finite membrane permeability and of longitudinal diffusion in the tissue are discussed. Computations are presented to show the effects of various biological parameters on the concentration profiles.