Blood Supply of the Brain Flashcards
Why is there more blood supply to the gray matter of the brain?
More cell bodies in the gray matter, hence more blood necessary
Define Autoregulation (Control of Blood Flow)
Vasoconstriction in response to increased blood pressure
Define Chemoreception (Control of Blood Flow)
Metabolites monitor carbon dioxide levels in the brain and increase/decrease flow respectively
What are the two sources of blood flow to the brain and by what percentage does each supply it?
Internal Carotid Arteries - 80%
Vertebral Arteries - 20%
What are the branches of the Internal Carotid Arteries?
Anterior Cerebral Artery Anterior Communicating Artery Middle Cerebral Artery Opthalmic Artery Anterior Choroidal Artery Posterior Communicating Artery
What does the anterior cerebral artery supply? Where are deficits seen with ischemia?
- Medial frontal, and parietal lobes, and the corpus callosum
- Contralateral motor and somatosensory deficits, greater in LE
What is the function of the anterior communicating artery?
Joins right and left anterior cerebral arteries
What does the middle cerebral Artery Supply? What deficits are seen with ischemia?
- Lateral Cerebral hemispheres (most pre/post central gyri)
- Major Motor and Somatosensory Deficits; Language deficits if in dominant hemisphere
What does the Opthalmic artery supply? What deficits are seen with ischemia?
- Orbital Contents
- Vision Loss
What does the Anterior Choroidal Artery Supply? What are the deficits that are seen with ischemia?
- supplies choroid plexus (lateral ventricles), optic tract, internal capsule, thalamus
- Contralateral motor and somatosensory deficits as well as vision problems
What is the function of the Posterior communicating artery?
Connects MCA to posterior cerebral artery
Where are the lenticulostriate and lateral striate arteries from and what do they supply?
- MCA
- Deep structures of the Telencephalon and Diencephalon
- These can be frequent areas of stroke because of disproportionate deficits due to thalamic connections
What do the vertebral arteries supply?
- most of the brainstem, cerebellum, and parts of the diencephalon, occipital and temporal lobes, also the spinal cord
What are the branches of the vertebral arteries?
- Posterior spinal arteries (paired)
- Anterior Spinal Artery (Unpaired)
- Posterior Inferior Cerebellar Artery (PICA)
What do the posterior spinal arteries supply?
Posterior 1/3 of that half of spinal cord
What does the anterior spinal artery supply?
Anterior 2/3 of spinal cord
What does PICA supply?
Inferior cerebellar surface, 4th ventricle choroid plexus, lateral medulla
What are the branches of the Basilar Artery?
- Anterior Inferior Cerebellar Artery (AICA)
- Superior Cerebellar Artery
- Pontine Arteries
- Labyrinthine Artery/internal auditory artery
- Posterior Cerebral Artery
What does AICA supply?
Anteroinferior Cerebellum and Caudal Pons
What does the superior Cerebellar artery supply?
Superoanterior cerebellum, caudal midbrain, rostral pons
What do the pontine arteries supply?
Remainder of pons
What does the Labyrinthine/internal auditory artery supply? What deficits are seen with ischemia?
- Inner ear
- Results in vertigo and ipsilateral deafness
What does the posterior cerebral artery supply? What deficits are seen with ischemia?
- inferomedial occipital/temporal lobes and posterior choroid plexus of 3rd ventricle
- visual field losses
What are the causes of Ischemic Strokes?
- Altered blood pressure
- Arterial Disease
- Blockage
