Vascular networks are complex capillary and venous microsystems that penetrate the connective tissue of the body, as well as connecting the walls of capillaries and post-capillary venules and ensuring the exchange of substances between blood and tissue. The structure and location of arterioles, capillaries and veins differs in different organs.
Capillaries are the smallest blood vessels that are of great importance in the functioning of the body. Due to the presence of capillaries, the effective distribution of metabolites and gases in tissues distant from the blood flow in large vessels is possible. Capillaries lie in porous connective tissue in close proximity to overlying blood vessels and thus control the distribution of metabolites between the blood and the interstitium. As a result, specific adaptive mechanisms of the vascular system make it possible to achieve the most effective functioning of tissues and organs. The exchange of substances between the interstitium and blood is regulated due to the permeability of the capillary membrane. It controls the equilibrium of the concentration of substances, which depends on