ABSTRACT
The function of the systemic arterial system is to deliver blood at high pressure and in a continuous stream to peripheral vascular beds. From a simplistic perspective, it can be separated into three anatomical regions to serve the left ventricle as a pulsatile pump and the tissues that need a supply of blood. Each region has a distinct and separate function: (1) The large arteries, especially the elastic arteries (aorta, brachiocephalic, carotid, etc.), serve predominately as a cushioning reservoir or ‘Windkessel’ that stores blood during systole and expels it to the tissue during diastole. (2) The long muscular arteries act predominately as conduits, distributing blood to the extremities; these arteries, also, actively modify wave propagation by changing smooth muscle tone and diameter with little change in mean arterial blood pressure. (3) The arterioles, by changing their caliber, alter peripheral resistance and, therefore, aid in the maintenance of mean arterial blood pressure, and the delivery of a steady or continuous flow of blood to the organs and tissues according to their need. Major changes in the central elastic arteries occur over long periods of time, while acute alterations in wall properties (e.g. with rise or fall in distending pressure) are passive (Nichols and Edwards, 2001; Giannattasio and Mancia, 2002). Changes in the muscular arteries and arterioles most often occur acutely and alterations in wall properties are active (Boutouyrie et al., 2000; Nichols and Edwards, 2001; Safar et al., 2003).
