Figure 7-4
Cerebral arterial circle (circle of Willis) on the brain base.

Interestingly, the neurons of the CNS are extremely specialized in accomplishing their mission of generation and conduction of electrical impulses. This specialization has rendered them incapable of storing oxygen and glucose. This critical limitation dictates that these neurons have a constant and adequate blood supply (1000 mls/min.). Without it, they will perish rapidly. Blood is supplied by a classic arterial anastomotic circle called the cerebral arterial circle (of Willis), located at the base of the brain. This arterial circle receives branches from two internal carotid arteries and two vertebral arteries. The four arteries meet at the arterial circle to supply all components of the brain. (Figure 7-4)