1. The brain (in most cases) comprises 2% of the entire body weight The brain utilizes 20% of the body’s oxygen 17% of the cardiac output goes to the brain

2. Arteries of the Forebrain Anterior Cerebral Artery Middle Cerebral Artery Posterior Cerebral Artery

3. Anterior Cerebral Artery Supplies most of the medial brain Arches over the corpus callosum

4. Middle Cerebral Artery Receives 80% of the internal carotid blood flow Located along the lateral fissure Two branches –Upper Frontal and parietal lobe –Lower Parietal and temporal lobes

5. Middle Cerebral Artery Supplies blood to 2/3 of the lateral surface The lateral striate arteries are an important site for strokes because it will lesion pyramidal track fibers at the internal capsule

6. Posterior Cerebral Artery 25% of the blood flow comes from the internal carotid artery Supplies occipital and temporal lobes

7. Blood Supply to the Brainstem Vertebral Artery –Posterior Inferior Cerebellar Artery Lateral side of the medulla –Anterior Spinal Artery Ventral and medial aspects of medulla –Posterior Spinal Artery Dorsal and medial aspects of the medulla

8. Blood Supply to the Brainstem Anterior inferior cerebellar artery –Supplies the lateral sides of the pons and the inner ear Pontine –Supplies midpons Posterior cerebral –Supplies the midbrain

9. Venous Drainage Superficial –Superior brain Superior sagittal sinus –Middle brain Cavernous sinus –Inferior brain Transverse sinus Deep –Great cerebral vein of Galen

10. Regulation of Blood Flow Autoregulation –H+ ion concentration –Intraluminar pressure