Fundamentals of Physiology and Biology of Vascular System

Abstract

Vascular system supports the homeostasis of our body through supplying adequate oxygen and nutrition to organs and retrieving wastes. This system is fundamental to maintain the physiological function of each organ connected to parallel fashion. Once vascular system becomes malfunction, the severe pathological condition threatening our lives occurs in our body. This is why vascular system finely adjusts the blood flow in corresponding to the demand of each organ. In this step, several regulatory mechanisms present in our body and a change of radius of arteries supplying to each organ is a major one. Radius of arteries is regulated by the dilation or contraction of vascular walls and the latter mainly contribute the regulation of blood flow. This contractile status of vascular system, regulated by the power stroke of heads of myosin along actin fibers driven by the increase of intracellular Ca²⁺ level, is termed as vascular tone. Because the disturbance of vascular tone can cause the pathological consequence in organs and our body such as shock, vascular tone is strictly regulated by many factors including both intrinsic and extrinsic ones such as renin-angiotensin system and sympathetic nerve system. In this chapter, we summarize the fundamentals of the physiology and also the biology of vascular system.