Ventricular System and Blood Vessels Flashcards
diffuse axonal shearing
when brain bumps up agains skull, get contusions, hemorrhaging and diffuse axonal shearing
= when axons pulled away from where they are supposed to be. disconnected from environment
Imaginary T shaped axis which defines the way sections are discribed in the brain
neuraxis
vertical componenet extends through central aspect of spinal cord and brainstem to level of diechephalon
horizontal component extends from the frontal to occiptital poles of the cerebral hemispheres on midline
Contralateral
refers to sensory or motor deficits occuring on the opposite side of the causative lesion
ipsilateral
refers to sensory or motor deficits occuring on the same side as the causative lesion
Modality
various sensory stimuli, working in isolation or combination, may elicit a particular form of sensation depending upon the number and type of receptors and teh receptor patterns or fields.
Somatotopic
some sensory or motor pathways convey their fibers in a highly organized, laminated fashion as they ascend or descend to dpecific regions of the cortex or body
cartoon representation of exaggerated proportions of the cortical map
homunclus
nucleus
aggregation of neuronal cell bodies in the CNS
ganglion
aggregation of neuronal cell bodies in the PNS
cortex
sheet like layer of gray matter covering the cerebral hemispheres.
Other names for gray matter
body, column, center, lamina
Funiculus
white matter
bundle of nerve fibers, nothing in particular
fasciculus
bundle of nerve fibers belonging to a particular system in the CNS
white matter
tract
specifically defined fasciculus of nerve fibers that have common origin, termination and function
white matter
Leminiscus
bundle of crossed, secondary nerve fibers in a CONSCIOUS SENSORY PATHWAY
(conveys information from the opposite side of the body)
white matter
What important things are found in the subarachanoid space
CSF and major arteries.
if you rupture an artery here, you bleed into subarachnoid space, blood present in CSF
Falx herniation
with unilateral space-occupying lesions of the cerebrum
herniate across midline beneath free edge of falx
may not present clinical deficits associated with herniation
Epidural hematoma
rupture of meningeal vessel
pt post-traumatic history is unconsciousness followed by rapid recovery
after a few hours, increase in supratentorial cranial volume causes herniation
profuse high-pressured bleeding, rapidly extends epidural space.
falx herniation or tentorial herniation
TX - emergency operation to evacuate the hematoma
tentorial herniation (aka_____)
uncal herniation
through the tentoial notch
displaces the midbrain, bilateral compression of the midbrain reticular formation results in progressive decrease in the level of consciousness
subdural hematoma
head trauma may cause cerebral veins to rupture as the cross subdural space
these veins are vulnerable to sheer forces created between movement of brain versus dura
space occupying hematoma in subdural space
signs and symptoms are same as epidural hematomas, but time onset may be delayed for days or weeks.
progression of signs and symptoms much more insididous. due to slower accumulation
can have acute onset
display various states of lethargy, seizures, or headaches.
inchildren associated with skull fracture, in elderly minor head trauma may result in subdural hematoma due to more fragile blood vessels
Trauma to the midbrain
result may be some degree of temporary or permanent coma, depending upon the amount of damage to the midbrain reticular formation.
RF is essential for consciousness
in most cases the superior sagittal sinus empties into
right tranverse sinus
in most cases the straigh sinus drains directly into
left transverse sinus
thrombosis of the posterior portion of the superior venous sinus or right transverse venous sinus results in
cortical ischemia and or necrosis
thrombosis of the posterior portion of th straight venous sinus or left tranverse venous sinus results in
ischemia and or necrosis of structures in the deep cerebrum. this is usually fatal.
Papilledema
increased ICP applies a cuff-like pressure to small veins on optic nerve, via the adjacent subarachnoid extension.
decreased drainage from retina results in edema of the retina and selling of optic disc
Subarachnoid hemorrhage
all major blood vessels of CNS pass through the subarachnoid space. rupture in the space is called subarachnoid hemmorhage, indicated by presence of erythrocytes in CSF.
cerebral contusion may also result in subarachnoid hemorrhage
what are the two subarachnoid cisterns
cerebellomedullary cistern (cisterna magna) - just above foramen magnum and posterior to the medulla superior cistern (cisterna ambiens) - located posterior to pineal gland
where is CSF resorbed
at arachnoid villi that protrude into the superior saggital sinus
how much csf is prduced each day
600-700 ml
arachnoid villi protrude where
into the venous lacunea
arachnoid villi have what functional stucture
small, pressure controlled valves, which drain most of the CSF, active and passive trasport
What is the pressure of the CSF
100-200ml of water
If CSF doesn’t get out of the ventricular system, you get
hydrocephalus
Can treat hydrocephalus with a shunt. they have to be replaced every so often because why?
glial cells clog the shunt
external hydrocephalus is defined as
excessive accumulation of CSF in subarachnoid space with
expansion of subarachnoid space that compresses the CSF
External hydrocephalus may be associated with one or both of what kinds of hydrocephalus?
Supratentorial external hydrocephalus
infratentorial external hydrocephalus
Supratentorial external hydrocephalus is most commonly associated with what
senile atrophy of the cortex ie alzheimer’s
infratentorial external hydrocephalus is seen in combination with what
communicating hydrocephalus
Internal hydrocephalus is sometimes called
noncommunicating hydrocephalus
internal hydrocephalus is due to
obstruction completely within the ventricular system
internal hydrocephalus results in
dilation of the ventricle(s) proximal to the obstruction
Communicating hydrocephalus is a combination of
infratentorial external hydrocephalus
and
inteernal hydrocephalus
in communicating hydrocephalus, obstruction of the subarachnoid space at the level of__________ may prevent the flow of CSF from _________ to ______ regions
the tentorial notch
infratentorial
supratentorial
this space may become obstructed due to adhesions and fibrosis in the subarachnoid spaces from past inflamation, cerebral edema or uncal herniation
In communicating hydrocephalus, CSF is free to move throug ________, but it cannot move_____
the ventricular system into the infratentorial subarachnoid space,
but it cannot circulate over the cerebrum to be resorbed at the arachnoid villi adjacent to and in the superior saggital sinus.
The result of communicating hydrocephalus
hypertrophy of the ventricles (internal hydrocephalus) and accumulation of CSF in the infratentorial subarachnoid space (external hydrocephalus)
TX of communicating hydrocephalus
shunt inserted into the cerebellomedullary cistern to train excess CSF.
In global ischemia, you run the risk of
watershed infarction
Cerebral attempt at compensation
when one blood vessel doesnt work, another may hyperperfuse
where the arterial “trees” overlap, tissue needs BF from both arteries. One trie dies, and the other must supply MORE blood –> hyperperfusion
Ischemic penumbra happens at around what level of regional cerebral blood flow
10-20 ml/100 gm tissue/min
What is the watershed region/ ischemic penumbra
following focal ischemia (stroke) the tissue surrounding the core ischemich territory that is too ischemic to function, yet critically viable
What is stroke therapy directed at? what is the mechanism?
Stroke therapy is directed at rescuing the ischemic penumbra (watershed region)
by improving tissue acidosis and oxygen delivery
Ca channel and NMDA receptor blocking drugs may prevent further neuronal damager
Cerebral blood vessels can autoregulate on a small scale. but what happens when the cerebral blood flow falls too low
autoregulation dysfunction and edema due to ischemic tissue acidosis and resultant “luxury perfusio” of adjacent normal tissue
Blood brain barrier is normally absent where
pineal body
area postrema
median eminence of the hypothalamus
Chemotherapy disrupts
the bbb in order to get large molecules in.
Two adjectives to describe the normal formation of the circle of willis
asymmetrical and incomplete
Rigidity
increased resistance to movement in all directions
Spasticity
increased resistance to passive movement in one direction
Anterior choroidal artery
supplies choroid plexus of lateral ventricle, basal ganglia, internal capsule, thalamus and rostral midbrain.
historical significance in neurosurgery (cooper saw decreased rigidity and tremors contralaterally in parkinson’s patients)
Penetrating arteries of the ACA supply
internal capsule and the corpus striatum (globus pallidus, putamen and caudate)
cortical branches of the ACA supply
anterior 2/3 of the medial side and supero-lateral portion of the hemisphere
right down center of forehead
area that supplies motor to leg and food (contralateral)
Penetrating branches of the MCA are called
they supply
medial and lateral striate or thalamostriate arteries
internal capsule, corpus striatum and thalamus
Cortical branches of the MCA supply
lateral aspect of the hemisphere
area that supply innervation to arm, forearm, hand, head
broca’s and wernicke’s areas
auditory
Dominance of hemisphere is established by
what side has language function
Broca’s aphasia is a language ________ disorder
expression disorder
Broca’s aphasia
nonfluent aphasia
dont talk a lot, swear
motor language disorder
characterized by cryptic, telegraphic speech, frustration in initiation of speech motor patterns
Wernicke’s aphasia is a ______ aphasia
receptive
wernicke’s aphasia
receptive language disorder
fluent (talkative)
lack content or meaning in their spoken and written comprehension of language.
inappripriate word choices and neologisms
internal voice just as messed up as your rambling voice
arteries that supply the spinal cord
anterior spinal artery
posterior spinal arteries
great anterior artery of adamiewicz
Central Cord Syndrome
result of disruption of blood flow to the anterior spinal artery
ischemia of central region of spinal cord
characterized by central necrosis and cavitation of the spinal cord and development of a syrnx
How are centrla cord syndrome and syringomyelia
by the onset of the neurological signs and symptoms
CCS has an abrupt onset with some amelioration of s/s
syringomyelia has a slow progressively worsening scenario
The great anterior artery of adamkiewicz usually arises from and contributes to
left intercostal or superior lumbar arteries,
anterior spinal artery
great anterior artery of adamkiewicz is the major supply to
the inferior two thirds of the spinal cord
clinical significance of great anterior artery of adamkiewicz
may be compromised secondary to thoracolumbar fracture or surgical repair of AAA.
can result in pt paralyzed from waist down, no bladder or bowel control
All the blood from the brain empties where
dural venous sinuses.
The ACA supplies what critical cortical area
paracentral lobule
The MCA supplies what critical cortical areas
primary motor cx premotor cx broca's speech area primary somesthetic cx primary auditory cx Wernicke's area
The PCA supplies what critical cortical area
primary visual cx
the ASpA has penetrating branched that supply
the central portion of the spinal cord
The PSppA has penetrating branches that supply
posterior 1/3 of the spinal cord.
