Mechanics of the Large Artery Vascular Wall

Abstract

The aorta and large arteries are generally thought of as conduit vessels whose main function is to provide a conduit for blood flow to reach the peripheral tissues. However, because the pressure and flow curves are not a simple ratio, it has long been recognized that the cardiovascular system functions in more complex fashion than merely a simple resistance to blood flow. Blood pressure is highest at the beginning of the systemic circulation; the decrease of blood pressure is not linear with vessel diameter or distance in the vascular tree. Blood pressure decrease ranges from 30 to 40% of the aortic pressure in vessels down from 250 to 50 µm in diameter [1–3] while most of the pressure drop occurs in the terminal arterioles with diameters smaller than 100 µm and which branch into numerous small capillaries. The site of the largest pressure drop may differ between tissues; however, in vessels smaller than 60 µm, no correlation has been found between the central arterial pressure and microvascular pressure which suggests that perfusion pressure is being controlled in these blood vessels and those with lower diameter [4].