Blood capillaries, function, management

Basic Information
The capillary wall consists of endothelium, basement membrane and only isolated pericytes. Pericytes can regulate vessel lumen. At rest, only 25-35% of capillaries are active. Capillaries are not evenly distributed throughout the body (from 300–400 per mm3 in striated muscles to 2500–3000 per mm3 in the myocardium).

The exchange of gases and substances takes place at the capillary level, the degree of permeability is influenced by the distribution of endothelium. We distinguish three types of layout:
 * Continuous endothelial lining,
 * fenestrated endothelium - permeable to water and small hydrophilic molecules,
 * Discontinuous endothelium - fully permeable to all plasma components.

By filtering the plasma through the capillary wall, tissue fluid occurs.

Related Articles

 * Tissue fluid