Blood supply to the brain Flashcards
What is the average brain blood flow per minute?
46ml/100g
Briefly describe how blood vessels in brain differ to other parts of the body
Arteries: thin walled, easily blocked
Veins: thin walled, no muscles of elasticity and no valves
What does the carotid artery supply?
80% of cerebral blood flow.
Anterior 2/3 of cortex (frontal, parietal, some occipital some temporal)
What do vertebral arteries supply?
20% of cerebral blood flow.
Brainstem, cerebellum some posterior cerebrum
Where does the carotid artery enter skull and where does it go to?
Carotid canal
Moves to cavernous sinus
Which 2 main arteries does it split into?
Middle cerebral and anterior cerebral
How do vertebral arteries travel up the neck?
Through transverse foramen of cervical vertebrae
What do vertebral arteries anastomose to form?
Basilar artery
How do posterior and anterior arteries connect?
Via the circle of willis
What does the basilar artery divide into?
Posterior cerebral artery
Main branch of anterior circulation?
Internal carotid artery
Name the four main branches of the internal carotid artery
Ophthalmic, middle cerebral, anterior cerebral, posterior communicating
What does the ophthalmic artery supply?
Orbit and retina
What does the middle cerebral artery supply?
Basal ganglia, internal capsule and lateral 2/3 of the cortex
What does the anterior cerebral artery supply?
Inner wall of frontal and parietal lobe
What does the posterior communicating do?
Links to vertebral system
How does the middle cerebral artery supply deep structures in brain?
Sends of striate arteries which supply internal capsule
Also supplies lateral 2/3 of cortex wall
What is the internal capsule?
Axon tract travelling to/ from the cortex
How does the anterior cerebral supply deep structures in the brain?
Comes forward over the corpus collosum to send branches to medial wall of cortex
Where is the primary motor cortex located? What vessel supplies it?
Parietal lobe on post central gyrus
Anterior cerebral
What do vertebral arteries supply?
Spinal cord, dorsal medulla of brainstem.
Also sends of posterior inferior cerebellar arteries
What vessels supply the pons?
Pontine arteries- branches of basilar
What vessels supply the cerebellum?
Anterior inferior cerebellar artery and superior cerebellar artery
What does the posterior cerebellar artery supply?
Inferior and medial aspects and temporal and occipital cortex
What does the posterior cerebellar artery (usually) anastomose with?
middle cerebral artery
What vessels supply the medulla
Part of anterior spinal
Lateral posterior part supplied by posterior inferior cerebellar artery
In which structure does the internal carotid artery make 2 acute turns?
Cavernous sinus
Where do the superficial cerebral veins cross?
Subarachnoid space
What 2 things drain into dural sinuses
CSF and venous blood
What do superficial cerebral veins drain into?
Dural venous sinuses
Which vessel does the majority of cerebral blood drain into?
Internal jugular vein
What is unique about cavernous sinus?
only place where artery travels through venous structure
Where do cerebral aneryms usually occur?
where an artery divides or where 2 arteries meet
Which is the most common artery to undergo an ischaemic stroke?
MCA
Symptoms of MCA stroke with dominant hemisphere
global apahsia
sensorimotor loss on colateral face upper limb and trunk
legs are fine
Symptoms of MCA with non dominant hemisphere
Neglect syndrome- if you ask them to draw a picture they forget the left hand side as right side of brain isn’t working
Symptoms of ACA stroke
Contralateral sensorimotor loss below waste
Urinary incontinence
Personality defect
Symptoms of PCA stroke
Contralateral homonymous hernianopsia
Reading and writing defects
Impaired memory
Symptoms of lateral medullary syndrome
Affects PICA
Vertigo, nausea and vomiting, dysaethia, dysphonia, loss of contralateral pain and temp in body
loss of ipsilateral pain and temp in face
loss of gag reflex
