Pharmacology of the blood vessel wall

Abstract

Changes in the degree of contraction of the smooth muscle cells of the blood vessel wall permit the control of vascular function at the different levels of the circulation. In the aorta and the large arteries, they adjust the stiffness of the arterial wall and, together with changes in peripheral resistance, modulate the impedance of the vascular circuit. At the level of the small arteries and the arterioles, active changes in vascular diameter regulate the blood flow to the individual tissues and, by altering the total peripheral resistance, also help determine the arterial pressure. Active dilation and constriction of the systemic veins, in particular those of the splanchnic area, adjust the total capacity of the cardiovascular system and thus control the return of blood to the right heart; active changes in the diameter of the cutaneous veins are a major determinant of the thermoregulatory function of the skin circulation. This overview briefly discusses the signals that alter the degree of contraction of the vascular smooth muscle cells.