Percolation and Transit in Microvascular Networks
Progressive microcirculatory obstruction interfering with normal tissue oxygen supply has been repeatedly demonstrated in various diseases in many organs (Knisely et al., 1947) and, in particular, in the ischemic brain cortex (Crowell and Olsson, 1972; Little et al., 1976). Both light microscopic and electron microscopic examinations have shown that cerebrovascular obstructions occur primarily at the capillary level and appear to be the result of the compressive effect of glial swelling and developing edema (Little et al., 1976), although changes in blood viscosity may play an important role, too (Dintenfass, 1971). In other experiments secondary reductions in regional blood flow as well as slow elevations of vascular resistance have been observed in permanent cerebral ischemia (Hossmann and Schuier, 1980; Shima et al., 1983). Late ischemic changes in blood flow were paralelled by rising tissue pressure and water content (Ianotti et al., 1985).
KeywordsTransit Time Percolation Threshold Capillary Number Capillary Density Mean Transit Time
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