Modeling substrate concentration in skeletal muscle

We adapt an approach developed for modeling oxygen transport in skeletal muscle, which allows the inclusion of a large number of capillaries, to the modeling of substrate transport. The substrate concentration in the capillaries is determined from the solution of a set of algebraic equations. The tissue concentration in any region is sufficiently approximated by the concentration in a nearby capillary, diminished by a finite amount that is determined along with the solution to the equations for the capillary concentration. We find that differently perfused adjacent or nearby capillaries interact and affect each other, but that this interaction is fairly localized.