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189 Cards in this Set

  • Front
  • Back
where are meninges located and what are they
membraneous coverings between the skull and the brain
two reasons why the brain is protected by the meninges
1. stabilize the shape and position of the brain since the brain is suspended within the meminges, which are anchored to the skull
2. teh buoyant effect of the cerebrospinal fluid (CSF) within the meninges decreases the effect of various forces on the brain.
what are the three meningeal layers
1. Dura Mater
2. Arachnoid
3. Pia Mater
which of the meningeal layers is the most thick? Substantial layer?
dura mater
which layer is attached to the inner surface of the skull
dura mater
what are the names of the two layers of the dura mater and what they are
1. outer layer: serves as the periosteum of the inner surface of the skull
2. inner layer: the meningeal dura
are these two layers tightly fused or do they have spaces between them if so...what are the spaces called?
througout most of the brain, the two layers are tightly fused but some parts have opening b/t the two-> contains sinuses
what are dural reflections
places where the inner dural layer folds in on itself as a sheet-like protrusion
falx cerebri
intervenes b/t the two cerebral hemispheres
tentorium cerebelli
separates the cerebrum and the cerebellum
tentorial notch
the space in the tentorium through which the brainstem passes
what partially separates the two cerebellar hemispheres
falx cerebelli
where do cerebral veins empty in
the sinuses
what are dural venous sinuses
sinuses formed by separation b/t the two dural layers
what are the four sinuses
1. superior sagital sinuse
2,3. transverse sinuses
4. straigt sinus
where is the superior sagital sinus found
along the attached edge of hte falx cerebri
how many surperior sagital sinuses are there
1
transverse sinuse
along the posterior line of attachement of hte tentorium
how many transverse sinuses
2- left and right
straight sinuse-where? how many?
along the line of attaachemnt of the falx cerebri and tentorium cerebelli- 1
what is the confluence of the sinuses
wehre all four sinuses meet
the course of the venous blood flow in the brain of the dural venous sinuses: flows posteriorly in the _________ and the ________
superior sagittal sinus and straight sinus
then to the
confluence of the sinuses
then to the
transverse sinuses
then continues as the
sigmoid sinus
then empties
into the internal jugular vein
what ist he arachnoid
a thin, delicate membrane that is semi- transparent
is it vasular or avasular
avascular- contains no blood vessels
the arachnoid adheres to the innermost layer of the _____.
dura
the arachnoid does not follow the contours of the brain which forms the
subarachnoid space
where is the subarachnoid space found
b/t the arachnoid and the pia mater
what is the subarachnoid space filled with
cerebrospinal fluid
large subarachnoid space filled with CSF->
cistern
blood vessels are or are not present in the subarachnoid space
are
generally the CSF in the subarachnoid space is separated from the
venous blood in the dural sinuses
the CSF enters the dural sinuses at many locations through
arachnoid villi
the arrachnoid villi is the major sites of
reabsorption of the CSF into the venous system
the arachnoid villi functions as what type of valve
one way
the arachnoid has a barrier function meaning whatq
blocks the entry of foreign matter into the brain
what is the pia mater
a thin, delicate, inner most layer
the pia mater closely follows the contours of the
brain
what is a hematoma
pool of blood in a location
bleeding in the meninges: what are the three parts of this
1. epidural hematoma
2. subdural hematoma
3. subarachnoid hemorrhage
where is epidural hematoma found
b/t the dural periosteum and the skull
what is periosteum
outer layer of dura
where is subdural hematoma found
b/t the meningeal dura dn teh arachnoid
where is subarachnoid hemorrhage found
in the subarachnoid space
increasing intracranial pressure may cause
parts of the CNS to herniate from one compartment into another
what is the pressure caused by
a hematoma or a tumor
herniation compressing the brainstem could be
fatal
what are the four ventricles
1,2. lateral ventricles
3. third ventricle
4. fourth ventricle
what are the 5 parts of the lateral ventricle
1. anterior horn
2. body
3. posterior horn
4. inferior horn
5. atrium or triagone
the anterior horn of the lateral ventricle is located anterior to the
interventricular foramen
what is the interventricular foramen
connects the lateral and 3rd ventricle
what lobe is the anterior horn found in
frontal lobe
which lobes is the body of the lateral ventricle found
in the frontal and parietal lobes
where does the posterior horn of the lateral ventricle project
projects backward into the occipital lobe
where iss the inferior horn of hte lateral ventricle found
curving down and forward into the temporal lobe
what is the atrium or triagone
the body and the posterior and inferior horns meet
the third ventricle occupies
the midline region of the diencephalon
the hole in the third ventricle is formed by the
massa intermedia
what is the massa intermedia (which we already learned
band of fibers that connect to thalamus
thalamus and __________ forms the wall
hypothalamus
the third ventricle connects to the _______ via _______ which traverses the ________
4th ventricle. cerebral aqueduct. midbrain
where is the fourth ventricle found
between the cerbellum posteriorly adn the pons and medulla anteriorly
what are the 3 apertures in the 4th ventricle
1. median aperture (foramen of Magendie)
2,3. 2 lateral apertures (foramina of Luschka)
what is the point of the 3 apertures of hte 4th ventricle
through which the ventricular system communicates wiht the subarachnoid space
what is the median aperture
a hole in the inferior medullar velum w hich empties into the subarachnoid space through cistern magna
ventricles are developed in the
center of hte neural tube
where is CSF housed
in the ventricles
what is the mean volume of CSF in adults
150 ml
how many ml is contained within the ventricles
25ml
where is the rest of the CSF
occupies the subarachnoid space
most of the CSF is produced by _____ which is in the ______
choroid Plexus which in the ventricles
describe choroid plexus
convoluted, membranous, vascular structure on the walls of hte ventricles
where is choroid plexus found
in all ventricles
rate of formation of new CSF
is relatively constant. the total volume of CSF is renewed 3 times/day
describe the circulation of hte CSF in the brain starting at the lateral ventricle
lateral ventricle. interventricular foramen. 3rd ventricle. cerebral aqueduct. 4th ventricle. median and lateral apertures. cistern magna and pontine cistern. tentorial notch. up over the cerebral hemispheres. arachnoid villi. superior sigittal sinus
describe the circulation of the CSF in teh spinal cord starting at the cisterns
cisterns. subarachnoid space around the spinal cord. lumbar cistern. moves back rostrally. along the way, into the venous system thru arachnoid villi.
what are the 2 functions of the CSF in the subarachnoid space
1. protecting the brain by buoyant effect- from banging it
2. providing spatial buffer effct- accomadates growth
functions of CSF: two ways of regulation of the extracellular environment of neurons
1. by controlling the composition of extracellular fluid
2 by removing the substances produced by the brain
disruption of the CSF circulation: what is hydrocephalus caused by
build-up of CSF in the brain
what are three things that hydrocephalus can result from
1. excess production of CSF
2. deficiency in CSF reabsorption
3. blockage of CSF circulation
what is the most common of the three
blockage of CSF circulation
what can blockage of CSF circulation be caused by (3)
1. obstruction can be caused by a tumor occluding the pathway
2. congenitally occluded apertures
3. or by meningeal adhesion due to meningitis
how can blockage of CSF circulation be treated
by implanting a shunt (draining)
blood supply to the brain arises from
the aortic arch
the aortic arch divides into
common carotid arteries
subclavian arteries
the common carotid arteries bifurcate into
internal carotid arteries
external carotid arteries
the internal carotid arteres are on which side of the skul
each side of the skull
what are teh two major vessels
internal carotid arteries
the vertebral arteries
what does the internal carotid arteries supply
most of hte telencephalon and much of the diencephalon
what does the vertebral arteries supply? where do they branch off from?
suplies the brainstem and cerebrellum. parts of the diencephalon, spinal cord, and occipital and temporal lobes. (supplies lower portions of brain)

branches off of sublavian arteries
what does the internal carotid arteries enter the brain through
the petrous portion of the temporal bone
what is the name of hte space that it enters
the subarachnoid space
what does teh internal carotid arteries further divide into
anterior cerebral arteries (ACA) and Middle cerebral arteries (MCA)
the internal carotids supply most of hte
cerebrum
the vertebral arteries arise from the
subclavian arteries
at the function b/t medulla and pons, fuse and from the
basilar artery
at the level of the midbrain, bifurcatesx into
two posterior cerebral arteries (PCA)
where do posterior inferior cerebellar arteries (PICA) arise from
the verbetral artery
the PICA supply the
interior surface of cerebellum and lateral medulla
the anterior inferior cerebellar arteries (AICA) arise from the ________ just rostral to the _______
basilar artery just rostral to the origin
the AICA supplies the
anterior portions of the inferior surface of cerebellum and caudal pons
superior cerebellar arteries arises from the
basilar artery
the superior cerebellar arteries supplies the
superior surface of the cerebellum, caudal midbrain and rostral pons
the pontine arteries supply the
pons
the internal auditory arteries supplies the
inner ear
occulsions can lead to
vertigo and ipsilateral HL
what is anastomosis
a mechanism which joins the subclavian artery system with the carotid artery system. ( anastomosis means connection of separate parts)
what is the the circle of willis (one word)
anastomosis
where is the circle of willis found? and what does it surround
at the base of the brain, surrounding the optic chiasm
what does the circle of willis connect
the anterior cerebral, internal carotid & posterior cerebral arteries of both sides
what ist he circle of willis connected by
one anterior communicating artery: right and left ACAs. paired posterior communicating arteries: intenal carotids and PCAs
where does teh anterior Cerebral Artery (ACA) run
medially
what does the ACA supply
the medial aspect of the frontal and parietal lobes
some extend onto the _________ surface of the hemisphere
dorsolateral
occlusions impacts what
portions of the precentral and postcentral gyri
occlusions cause...?
what side? (contralateral,ipsilateral)?
upper or lower extremities?
restricted contralateral motor (especially, lower extremities) and somatosensory deficits. (if problem is on right side of brain, then will effect left side of body)
where does the Middle cerebral artery (MCA) emerge from
the lateral sulcus
what does the MCA supply
most of the lateral surface of the cerebral hemisphere. most of the precentral and postcentral gyri
occlusion cause
major motor and somatosensory deficits.
what part of body does occlusion effect
upper body and face
what will a left MCA lesion most likely result in
aphasia
what is the name of hte branches of MCA
lenticulostriate arteries
what do the lenticulostriate arteries supply
deep structures of the diencephalon and telencephalon including basal ganglia, internal capsule, insula
what is the lenticulostriate arteries frequently invovled in
strokes
lesion to these branches are ______, espeically that invovling the _______
devastating, internal capsule
the Posterior cerebral artery (PCA) supplies...
medial and inferior surfaces of the occiptial and temporal lobes. rostral midbrain. posterior parts of the diencephalon. splenium of corpus callosum
what is corpus callosum. is it found at upper or lower portion
major fiber connecting two hemispheres found at lower portion
occlusion of PCA can result in
visual field losses
a lesion invovling PICA or AICA will result in what behavior
ataxia (motor coordination difficulty)
lesion involving PCA will result in what behavior (3)
hemianopsia (visual field cut in the contralateral side). alexia without agraphia (reading problem without a writing problem) amnesia
lesion involving MCA will result in what behavior? and what region?
aphasia (LEFT SIDE ONLY). hemiplegia, hemiparesis, hemianaesthesia

primarily effect upper region
hemiplegia
complete paralysis
hemiparesis
weakness
hemianaesthesia
sensory problem
a lesion invovling ACA will reslut in what? and what region?
hemiplegia and hemianaesthesia.

primarily effect in lower extremities
cerebral veins divide into (2)
superficial veins
deep veins
2 characteristics of superficial veins
drains the cortex. empty into the superior sagittal sinus
2 characteristics of deep veins
drains internal structures. empty into the striaght sinus
3 mechanisms of blood flow control to the CNS
1. autoregulation
2. metabolic mechanism
3. neural control
autoregulation
allows blood vessels to contrict in response to increased blood pressure and relax in response to decreased pressure
metabolic mechanism
vessels dilate with increased CO2 levels and contrict with decreased CO2 levels. dialate to increase flow and get more oxygen. constrict bc dont' need as much oxygen.
autoregulation is a way to keep blood flow (one word)
constant
perfusion pressure
normal blood pressure in brain.
what allows the blood flow to circulate
difference in pressure b/t arterial, intracranial (CSF) and venous pressure
hypoperfusion pressure
no pressure difference b/t the 3 systems.
hypoperfusion pressure causes what to happen to circulation of blood
decrease
what is effected by hypoperfusion pressure
distal branches of the 3 cerebral arteries (MCA ACA PCA)
what does hypopefusion pressure cause
diffuse sign behaviorally
what occurs with hypoperfusion pressure
water shed lesions
what are the three types of ischemic strokes
thrombosis, embolism, transient ischemic attach
what is ischemic strokes
caused by sudden vascular insufficiency
what is thrombosis caused by
generally caused by occlusion of blood vessels at the site. typically caused by atherosclerosis
what is atherosclerosis
plaque build-up
embolism is caused by? what is the characteristic of embolism?
hear disease. no plaque build up. main characteristic- the embolus is moved to the distant part of the body and gets lodged.
what are teh behavior signs of bothe the thrombosis and embolism
similar in both. slurring. headache
how long after a stoke is their damage
irreversible damage starts occuring in 2 minutes
whawt is transient Ischemic Attack (TIA)
temporary occlusion of blood vessel.
how long do deficits of a (TIA) persist
only for a few minutes to hours.
describe the resolution of TIA
spontaneous, complete.
what is TIA often caused by
minute emboli which become broken down.
what is intracerebral hemorrhage
bleeding into the brain.
what does intracerebral hemorrhage result from and what is it due to
rupture of small arteries, often due to hypertension
what is hypertension? what does it do to blood vessels?
high blood pressure. overtime changes shape of blood vessels- makes them thinner. they burst like a balloon.
what is an aneurysm
balloon-like swellings of arterial walls.
where do aneurysms most frequently occur
near or at the bifurcation of arteries
what does an aneurysm cause
neurological deficits by compression brain structures. by rupturing and causing a subarachnoid hemorrhage.
what is arterial venous malformation (AVM)
abnormal coupling of the arterial and venous system. congenital malformation.
what may occur with AVM
hemorrhage
what are neurons
cells specialized for sending and receiving signals
what are the 2 mechanisms for conveying info
electrical and chemical
electrical
within a neuron
chemical
between neurons
soma
cell body
what does the soma do
integrates electrical signals. supports the metabloic needs of the rest of the neuron
dendrites
reveive information from other neurons via synaptic contacts
axon
single, cylindrical fiber.
what does the axon do
conduct information away fromt he cell body to other neurons.
is the axon myelinated
may or may not be
axon terminals (synaptic endings) form
synapses on other neurons
how is the type of neuron determined
by the number of processes in the particular neuron
list the 3 types and say what each is
1.unipolar: one process which divides into the receiving and conducting part.
2. bipolar: one axon and one dendrite
3. multipolar: most common type. multiple dendritic projections
cell membrane
semi-permeable.
protein molecules embedded in the membrane do what
provides channel for certain ions to enter/leave
channels are what
voltage-gated.open/close in response to changes in teh electrical potential across the membrane
neuron excitation
unequal ion concentration across the cell membrane causes electrical potential difference.
what is the resting membrane potential
-70 mV (negative inside the cell)