Cerebrovascular Anatomy and Hemodynamics

Abstract Understanding the anatomy and hemodynamic relationships of the cerebral vasculature is critical to an appreciation of the importance of these relationships in the control of the cerebrovasculature in normal and pathophysiological (disease) conditions. The cerebrovascular anatomy and the complexity of the arterial, venous, and capillary systems, and the blood–brain barrier and capillary permeability are briefly described. The chapter then provides an overview of cerebrovascular hemodynamics considering the basic physical principles of flow of fluids through tubes and blood vessels. Consideration is given to general hemodynamic principles of Poiseuille's law, perfusion pressure or driving pressure for flow, vascular resistance to flow, the influence of viscosity and blood vessel diameter/radius, blood volume, and autoregulation. These principles are then applied to the cerebral circulation, and cerebral pressure–volume and pressure–flow relationships are discussed.