The Microcirculation of Normal and Injured Tissue

Abstract

The response of the microcirculation after tissue injury is recognized as a critical link in the chain of events which leads to tissue repair. However, tissue injury is but one of a number of perturbations with which the microcirculation must cope if the organism is to survive. General or localized changes in arterial and venous pressure for example constitute another potentially life-threatening situation. Appropriate homeostatic mechanisms exist to maintain a suitably low capillary pressure in the liver and intestine where the capillary filtration coefficient is high (i.e. 20–40 times greater than skeletal muscle) during venous pressure elevation in that region. Adequate flow must be maintained to vital organs during localized or systemic hypotension. A variety of mechanisms exist in the microcirculation to maintain constancy of capillary flow and pressure under such circumstances. Local regulation of blood flow must also be linked to the metabolic requirement of the tissue.