Microcirculatory mass transfer

The dynamics of Krogh tissue cylinders and related structures are critically reviewed to determine the roles of underlying transport and reaction processes, and the interactions between them. Emphasis is put on the gaining of insight through efficient scaling procedures, and discussion is organized about the time constants characteristic of these structures and the processes occurring in them. The basis of discussion is a new analytic solution technique which provides a formal description of indefinitely large arrays of parallel interacting elements and which includes both axial diffusion and uniform convection as well as first or zero order reaction within each element. The solution has the form of an expansion in the eigenfunctions of a non-self-adjoint differential operator. Comparison of model predictions with previously available results identifies the useful parameter ranges of analytic approximations and determines the accuracy of existing numerical procedures.