Vascular Organization of the CNS

the posterior and medial cerebellum is supplied by

PICA

What are the terminal branches of the basilar artery?

Superior cerebellar arteries Posterior cerebral arteries

the labyrinthine a. runs directly superior to _______

CN VI

When the right and left vertebral arteries meet, they become the

basilar artery

A vertebral artery dissection would cause a ______ stroke

brainstem stroke

labyrinthine artery

branch of either basilar or AICA, passes through internal acoustic meatus and supplies blood to the membranous labyrinth of internal ear

the rate of blood flow to specific brain regions changes based on activity. this change is thought to be regulated by ________.

astrocytes

the posterior cerebral artery and anterior cerebral artery may anastomose in what region of the brain?

at the posterior parietal lobe where it meets the anterior occipital lobe

the ICA is the primary blood supply to the

diencephalon and cortex

Why is the vertebral artery prone to dissection?

it has a vulnerable position between C1 and the skull base, so that any hyperextension of the neck can cause compression of or damage to the artery

The second branch of the basilar artery found immediately superior to the AICA (or branching from AICA directly) is the ______

labyrinthine artery

the branches of the MCA supplying the basal ganglia are called the

lenticulostriate arteries

the vertebral artery is the primary blood supply to the....

medulla, pons, midbrain

the posterior cerebral arteries supply the

midbrain, medial occipital and temporal lobes

the most common sites of an AVM are areas supplied by the _____ arteries

middle cerebral arteries

After the ICA enters the circle of Willis, it leaves as the _______

middle cerebral artery

Which artery supplies the basal ganglia?

middle cerebral artery

Is the circle of Willis able to provide collateral circulation in cases of sudden arterial blockage?

no - works for slow buildup, by equalizing pressures and redistributing flow over time

Pontine arteries include the (3)

paramedian aa., short circumferential aa., long circumferential aa.

the basilar artery runs on the _____ surface of the medulla

rostral (anterior)

the superior cerebellar arteries supply

rostral cerebellum, dorsal pons

Symptoms of AVM

seizures, headaches, hemorrhagic stroke, hemorrhage with progressive deficits

lenticulostriate arteries

small, deep penetrating arteries that branch from the middle cerebral artery

the posterior cerebral arteries, branches of the _______, are found just superior to what structure?

the basilar artery; just superior / caudal to CN III (oculomotor n.)

the AICA is a branch of ______ that runs directly inferior to the ______

the basilar artery; runs with CN VI

nidus

the central part of an AVM; a large cluster of blood vessels

the superior cerebellum is supplied by

the superior cerebellar arteries

How are astrocytes theorized to affect blood flow?

they pick up stray glutamate from synapses with their receptors, as part of the recycling process Glutamate binding then causes them to release vasodilating factors from their end feet, which are in contact with blood vessels

the vertebral artery courses through the _______ en route to the skull, then passes through the _______ after coursing posteriorly over C1.

transverse foramina; foramen magnum

the ______ artery is especially prone to dissection due to its position.

vertebral

blood supply to the brain is derived from the _______ and the ______

vertebral a. and internal carotid a.

Ruptured AVM occurs most commonly during which decades of life?

2nd, 3rd, 4th

the posterior and lateral cerebellum is supplied by

AICA

Name the 3 sets of arteries from the basilar artery in order of the direction blood flow.

AICA, labyrinthine (may come from AICA), pontine

Describe the Circle of Willis

Collateral circulation Joining of vertebrals & carotids

the anterior cerebral arteries supply the

Medial surfaces of the cerebral hemispheres

______ is the leading cause of stroke in young people

arterial dissection

radicular arteries

Small branches from the spinal arteries branching off the intercostal, vertebral, lumbar and lateral sacral arteries that supply the roots of the spinal nerves and their meninges.

Pseudoaneurysm

a contained rupture of a blood vessel that is most likely secondary to the disruption of one or more layers of that vessel's wall

What is an AVM and how does it form?

a direct arterial-venous connection with absence of a capillary bed the differential pressures between the 2 systems causes a ball of twisted collaterals to form

middle cerebral artery

a direct continuation of the internal carotid artery that supplies the lateral cortex

Radicular arteries anastomose with the....

anterior and posterior spinal arteries

Due to blood supply patterns to the motor and sensory cortex, blockage of the _______ artery can cause lower limb paralysis, while blockage of the ______ artery would paralyze the upper limb, trunk, and face.

anterior cerebral a. middle cerebral a.

the anterior cerebral arteries are connected by the

anterior communicating artery

the first and largest branch of the basilar artery is the

anterior inferior cerebellar artery (AICA)

the branch of the vertebral artery which is seen fusing with its paired artery at the midline of the medulla is the

anterior spinal artery

the ICA is more ______ to the vertebral artery and enters the skull through the ______, located where?

anterior; carotid canal located just below the middle ear cavity

paraplegia following aortic aneurysm repair is often due to

clamping of the aorta during repair causes ischemia of the ventral spinal cord, where motor neurons reside, because aortic blood can no longer supply the anterior spinal artery

AVM rupture is markedly more common in what population?

cocaine users

the course of the anterior cerebral artery involves curving around the

corpus callosum

when do AVM's usually form?

in late childhood or early adulthood

anterior cerebral arteries are branches of the _______ and run where?

internal carotid arteries; between hemispheres

the third branching point of the basilar artery is a cluster of paired arteries called the _______

pontine arteries

the middle cerebral artery is connected to the posterior cerebral artery by the

posterior communicating artery

the posterior cerebral artery gives rise to the ______, which enters the circle of Willis

posterior communicating artery

purpose of circle of willis

provide redundant pathways for blood flow to regions of the cerebral cortex, equalize pressure and flow of blood

Are AVMs usually deep or superficial?

superficial

What is a cerebral arterial dissection?

tear in the endothelium / intima traps blood inside the arterial wall, which can narrow the blood vessel or cause a bulging pseudoaneurysm

CN VI (abducens n.) separates what 2 vessels on the anterior medulla?

the AICA (inferior) and the labyrinthine artery (superior)

3 branches off the vertebral artery at the medulla are...

the PICA (posterior inferior cerebellar artery) Posterior spinal a. (often a branch of PICA) Anterior spinal a.

blood supply to the spinal cord is by

the anterior and posterior spinal arteries, supplemented by branches of the aorta (intercostal aa., lumbar aa. --> spinal aa. --> radicular aa.)

As the ICA enters the brain, it gives off bilateral anterior branches that run between the hemispheres. What are these called?

the anterior cerebral arteries

the superior cerebellar arteries, branches of the _______, are found just inferior to what structure?

the basilar artery; just inferior / rostral to CN III (oculomotor n.)