The circle of Willis
provides alternate pathways for blood to reach brain tissue in the
case of impaired blood flow in this system
The circle of Willis is
comprises of a communiqué of arteries at the bottom of the brain
comprising of the internal carotid arteries, anterior cerebral
arteries, posterior communicating arteries, posterior cerebral
arteries, and basilar arteries.
The
circle of Willis also permit blood to flow crosswise the midline of
the brain.
The
circle of Willis thus aids as a security valve role for the brain,
permitting collateral to take place if the flow is abridged to one
area.