Blood Supply To The Brain Flashcards
What arteries provide 80% of the brain?
The internal carotid arteries
What arteries provide 20% of the brain
The vertebral arteries
What parts of the brain do the internal carotid arteries supply>
- most of the telencephalon
- much of the diencephalon
What parts of the brain do the vertebral arteries supply?
- the brain stem
- the cerebellum
- parts of the diencephalon
- the spinal cord
- occipital and temporal lobes
The internal carotid artery is a continuation of what artery?
The common carotid artery
Where does the internal carotid artery veer anteriorly?
At the temporal bone
What is the small branch the internal carotid artery gives off in the carotid canal?
Ramus caroticotimpanicus
What does the internal carotid artery enter the skull through?
The carotid canal
The internal carotid artery passes through___________ and the _____________ at the base of the skull
Passes through the cavernous sinus and the subarachnoid space
The ophthalmic branch of the internal carotid artery leaves the skull through what?
The superior optic foramen
The ophthalmic branch of the internal carotid artery gives rise to what artery?
The central retinal artery
What are the two smaller branches the internal carotid artery gives rise to?
- anterior choroidal artery
- posterior communicating artery
The continuation of the internal carotid artery is called what?
The middle cerebral artery
As the two anterior cerebral arteries enter the longitudinal fissure, they are connected by what?
The anterior communicating artery
The anterior cerebral artery curves around __________ to supply __________________
Curves around the corpus callosum to supply the medial parts of the frontal and parietal lobes
The anterior cerebral artery continues as what artery?
The pericallosal artery
Occlusion of an ACA causes restricted contralateral motor and somatosensory deficits affecting what?
The leg more than any other part of the body
The middle cerebral artery proceeds posteriorly in what?
The lateral sulcus
The middle cerebral artery emerges from the lateral sulcus to supply what?
Most of the lateral surface of the cerebral hemisphere
Occlusion of the MCA causes major motor and somatosensory deficits in what?
The upper body and head
If the left hemisphere is involved in the occlusion of an artery, what kind of deficits would be seen??
Language deficits
What are lenticulostriate arteries?
12 small branches off of the MCA that penetrate the brain and supply deep structures of the hemispheres
Narrow, thin-walled vessels of the anterior perforated substance are involved frequently in what?
Strokesssssssssss
The vertebral arteries run rostrally through what?
The foramina of the lateral processes of the spinal vertebrae
The vertebral arteries enter the skull through what?
Foramen magnum
The vertebral arteries fuse together at the junction between the medulla and pons to form what?
Midline basilar artery
What are the three branches of the vertebral arteries?
- posterior spinal artery
- anterior spinal artery
- posterior inferior cerebellar artery
What does the posterior spinal artery supply?
The posterior third of the posterolateral aspect of the spinal cord
That anterior spinal arteries fuse to make what?
1 single anterior spinal artery
What does he anterior spinal artery supply?t
The anterior 2/3 f the spinal cordo
Why must the posterior and anterior spinal arteries be refilled at various points?
They are small and cannot carry enough blood from the vertebral arteries to supply more than the cervical segments of the spinal cord
What are the main branches off of the basilar artery?
- anterior inferior cerebellar artery
- superior cerebellar artery
What does the basilar artery do at the level of the midbrain?
Bifurcated into the two posterior cerebral arteries
What supplies the pons?
Pontine arteries off of the basilar artery
The perforating branches off of the posterior cerebral artery supply what?
The thalami
Choroidal branches off of the posterior cerebral arteries supply what?
The choroid plexuses od the third and lateral ventricle
What supplies the visual cortex?
The medial occipital cortical branch off of the posterior cerebral artery
What does the circle of willis connect??
The internal carotid and vertebral-basilar systems
Is there normally a lot or a little blood running through the posterior communicating arteries?
A little
Technically, if a major vessel becomes occluded in the circle of willis, the communicating arteries would allow flow and prevent damage, but in reality…
The communicating arteries vary in size and are normally not sufficient to ensure functional anastomoses
Successful vascular flow rearrangement depends on…
How fast the arterial occlusion occurs
Is it normal to have one or more of the communicating arteries extremely small or even absent from the circle of willis?
Sure. Asymmetries are common
Where is the venous drainage of the brain located?
Between inner and outer layers of dura mater
Blood collected by Duran venous sinuses drains ultimately into what?
The internal jugular veins
Why do cerebral veins not have valves?
Because the brain sits above the heart. No need like normal veins
What is autoregulation?
Process where cerebral blood vessels act to maintain constant flow
Arterial and arteriolar smooth muscle cells are directly stretch sensitive meaning…
Vessels constrict in response to increased blood pressure and they relax in response to decreased pressure
An increase in PaCO2 has what impact on vessels?
Vasodilation increases and so does cerebral blood flow.
NO is a potent…
Vasorelaxant
Acidosis has what impact on vessels?
Vasodilation
A cerebral angiography is produced by introducing a catheter where?
Into the femoral artery, threading it up the aorta and then into the artery of choice
