Blood+supply+to+the+brain

= The supply of blood to the brain can be divided into arterial territories. =

Blood travels from the heart through the aortic arch and into the carotid and vertebrobasilar arterial systems. All of the arteries supplying blood to the brain arise from the aortic arch. These arterial systems join at the base of the brain to form the circle of Willis. The circle of Willis gives rise to branches that travel to the surface of the cerebral cortex, interior of the brain, cerebellum and brainstem. The brain accounts for just 2% of our body weight but receives 15% of resting cardiac output and consumes 20% of the oxygen produced by the cardiovascular system. Anterior Circulation - The Carotid Arterial System The anterior or the carotid arterial circulation includes the external and internal carotid arteries that branch off of the common carotid arteries. The carotid arterial system supplies blood to most of the cerebral hemispheres via the middle and anterior cerebral arteries. Deep branches of the carotid arterial system supply blood to the subcortical regions of the brain such as the basal ganglia and the thalamus. Lesions in the carotid arterial system may cause damage to structures supplied by any or all of its three clinically important branches: 1. The ophthalmic artery 2. The anterior cerebral artery 3. The middle cerebral artery Posterior Circulation - The Vertebrobasilar Arterial System The posterior or vertebrobasilar arterial circulation includes the two vertebral arteries that join to form the basilar artery. The vertebrobasilar system supplies blood to the posterior part of the cerebral hemispheres including the occipital lobes and the posterior portions of the temporal lobes, the cerebellum and the brainstem. Lesions in the vertebral and basilar arteries may cause damage to any of the structures supplied by their clinically important branches including: * Brainstem * Cerebellum * Occipital lobe * Temporal lobe