1) Blood Supply And Ventricles Flashcards
What produces CSF? Specifically what areas?
The choroid plexus
Primarily lateral ventricles & 4th ventricle
What is the location of each of the 4 interconnected ventricles?
Lateral x2 - in each cerebral hemisphere
Third ventricle -> between thalami
4th ventricle -> between cerebellum & pons
This one’s a doozy…
What’s the path of CSF to the venous system?
Lateral ventricles > interventricular foramina of monroe > 3rd ventricle > cerebral aqueduct > 4th ventricle (can go to central canal of spinal cord from here) but to the brain venous system > median & lateral aperatures > subarachnoid space > arachnoid granulations > superior saggital venous sinus
What is the increase in cerebral mass/size due to presence of excessive CSF known as?
Hydrocephalus
If the ventricles are normal size and compression of the CNS is occurring, where is the CSF accumulating?
What disease is this most commonly associated with?
In the subarachnoid space is where the CSF is
This is known as external/communicating hydrocephalus
Alzheimer’s disease
What is it called if the CSF isn’t draining but stays in the ventricles?
Internal/noncommunicating hydrocephalus.
Which CN is usually the first to be affected by hydrocephalus?
Abducent (VI)
- no LR activity
- internal strabismus
What is batson’s plexus?
Internal venous plexus: Receives drainage from veins in the spinal cord, it is in the epidural space, and empties into intervertebral veins and then segmental veins
What does the internal cerebral vein drain, and drain to?
It receives thalamostriate and anterior septal veins.
Drains into great vein of Galen.
Okay… just study the veins in the brain
Do it.
What are the 3 locations in the brain where there is no blood brain barrier?
Pineal body
Area postrema
Median eminence of hypothalamus.
What is the purpose of astrocytes in the brain?
Secrete paracrines that promote tight junction formation, which prevent solute movement between endothelial cells.
What is the clinical presentation of occlusion of the anterior cerebral artery?
Contralateral paresis and/or parasthesia of the leg and foot
SENSATION & MOTOR TO THE LOWER EXTREMITIES
Branches of the middle cerebral artery (its a big one)?
Central artery - Primary motor
Frontal branches - premotor & prefrontal cortices. broca’s speech area (usually on left side)
Partietal branches - Association cortex
Temporal branches - Primary auditory
Angular artery - Wernicke’s area (usually left side)
Clinical presentation of middle cerebral artery occlusions, based on branches?
Central artery > contralateral spastic paralysis, and paresthesia of head and upper 1/2 of body
Frontal branches > broca’s aphasia = can hear and comprehend but cannot respond
Parietal branches > Body neglect, agnosia, and apraxia
Temporal branches > difficulty localizing sounds
Angular artery > Wernicke’s aphasia = fluent in speech, but lacks meaning
What is impaired if you have ischemic necrosis of the spinal cord in the inferior 2/3?
Blood flow thru the great anterior artery of adamkiewicz is impaired
It is the main supply to the inferior 2/3 of the spinal cord
What is central cord syndrome caused by?
How does it clinically present?
Disruption of blood flow to the anterior spinal artery.
Thrombosis or hyperextension injury of the neck.
Lose function in upper extremity more than lower, and distal musculature more than proximal
What is the cause of wallenberg syndrome (lateral medullary syndrome)?
What is wallenberg syndrome?
Occlusion of the posterior inferior cerebellar artery (branch of vertebral artery).
Loss of sensation, pain and temperature specifically.
What is the main artery of the internal ear?
What happens if injured
Labyrinthine artery - branch of basilar artery, or off of AICA
Disturbs equilibrium and/or hearing
What happens if the posterior cerebral artery is occluded?
Contralateral homonymous hemianopsia with macular sparing
What separates the two hemispheres?
Falx cerebri
If the falx cerebri is damaged what’re the clinical symptoms?
Headache, contralateral leg weakness… may not be clinically presenting at all!!!!
What does an uncal (tentorial) herniation cause?
CN III compression/palsy
What does tonsilar herniation lead to?
Respiratory arrest
cerebellar tonsils herniate through formamen magnum
