Brain consumes approximately 20% of the available oxygen for the normal function and physiological coordination. Auto-regulation of the cerebral blood flow is the most essential requirement irrespective of perfusion pressure and vascular resistance. The networking of the vascular bed is highly regulation in order to maintain constant blood flow and water homeostasis.

Cerebral hemodynamics is mainly regulated with pressure difference between inflow and outflow (Gotoh, 2014). Flow of blood is mainly calculated on the basis of ration between pressure difference and vascular resistance. This pressure difference is based on cerebral partial pressure and difference between intra-arterial pressure and pressure in veins.

This relationship is in accordance with Ohm’s law. Likewise, the flow is also calculated based on the equation of Poiseuielle’s law, taking into the account of blood viscosity, length and radius of the vessel. It is noteworthy to mention that even a minute alteration in the lumen diameter of the blood vessel is responsible for affecting the cerebral blood flow in a significant manner (Koller & Toth, 2012).