Tissue model, Krogh capillary

A vast amount of work is being done to describe quantitatively the - transport of anabolites and metabolites in the microcirculation of the brain. The classical geometry for the capillaries and tissue has been the Krogh capillary-tissue cylinder. Recent investigations have considered other geometrical configurations to determine if other models derived for multicapillary systems are more descriptive than the single capillary structure used here. 

To simulate the histological complexity of capillary-tissue arrangements in a better way and to develop an alternative concept to the Krogh model, a three-dimensional network system is suggested here, providing for differences in directions and flow velocities within the branches of the network (Figure 1). 

Figure 1.11 Geometry of the Krogh cylinder-type model. The inner cylinder represents the capillary the outer cylinder corresponds to the tissue cylinder. Shaded area example of hypoxic region under conditions of high demand. Rt, tissue cylinder radius Rc, capillary radius z, distance along the capillary. (From McGuire and Secomb, 2001.)...

Figure 8.2 Cylindrical geometry of the Krogh-Erlang model of blood-tissue exchange. The upper panel, from Middleman [141], illustrates the assumed parallel arrangement of capillaries with each vessel independently supplying a surrounding cylinder of tissue. A diagram of the model geometry is provided in the lower panel. Figure in upper panel is reprinted with the permission of John Wiley Sons, Inc.

Figure 1. Tissue lump-capillary lump Krogh cylinder model...

Krogh tissue cylinder model A cylindrical volume of tissue supplied by a central cylindrical capillary. Myogenic response Vasoconstriction in response to elevated transmural pressure and vasodilation in response to reduced transmural pressure. 

Impulse Response for the Krogh Cylinder Model with Plug Flow in the Capillary (Phase 1), Finite Diffusional Resistance Perpendicular to Flow Direction in the Tissue (Phase 2) and No Resistance at the Capillary Wall (Phase Boundary). Equivalent to Case 2. 

---