ABSTRACT

The cardiovascular system transports oxygen and nutrients to all tissues and removes carbon dioxide and waste products of metabolism by continuously circulating its working fluid, blood, through an elaborate hydraulic network of large and small vessels. Blood flow in humans is neither turbulent nor completely laminar. In the arteries the flow is pulsatile and intermittently accompanied by small disturbances, but in the vicinity of curvatures (bends) and branches, where secondary flows are generated, the patterns are unsteady and complex. By contrast, blood flow in veins is generally quasi-steady. Flowing blood continuously exerts mechanical forces on the vascular wall and the vessels adapt to this hemodynamic environment accordingly. At physiological levels, blood-imposed forces play an important role in maintaining normal biology of vascular wall cells. By contrast, in aberrant situations the hemodynamic challenges result in abnormal cellular responses that may lead to various vasculopathies.