LECTURE 4- circulations to the brain and spinal cord Flashcards
where is the CSF formed
in the ventricles (choroid plexus)
where does the CSF flow
between ventricles and into subarachnoid space
what is the function of the csf and meninges
provide shock absorption to brain
where is the csf absorbed into
the venous system
what is below the 2 C shaped lateral ventricles of the brain
thalamus
what is above the body of the 2 C shaped lateral ventricles of the brain
corpus callosum
what connects the 2 c shaped lateral ventricles and the 3rd ventricle
interventricular foramina (foramina of monro)
where is the 3rd ventricle
narrow in midline of diencephalon
what is teh 3rd ventricle surrounded by
thalamus and hypothalamus
what connects the 3rd and 4th ventricle together
cerebral aqueduct (aqueduct of sylvius)
where is the 4th ventricle
posterior to pons and medulla and anterior to cerebellum
where does the 4th ventricle connect to
central canal of SC
where does the 4th ventricle drain to
subarachnoid space
the 4th ventricle draining into the subarachnoid space thru ______ and midline of foramen of magendie
2 lateral foramina (foramina of luschka)
what is the outer layer firmly attached to inside of skull and inner layer attached to arachnoid
dura mater
the inner and outer layers of the dura mater fuse except at the
dural sinuses
what does the dural sinuses collect
CSF and venous blood
the inner layer of the dura mater has 2 dense projections called
flax cerebelli and tentorium cerebelli
what does teh flax cerebri seperate
the l and r hemispheres
what does the tentorium cerebelli separate
cerebellum from the hemispheres
what has grandulations that go thru dura into venous sinuses to allow CSF to flow into them
arachnoid mater
what is tightly fixed to the brain and SC surfaces
pia mater
the pia mater is connected to arachnoid through what
arachnoid trabeculae (collagen fibers ) to allow suspension of brain in CSF
what secretes the most CSF
choroid plexuses
what are the 3 layers of the formations of CSF
web of capillaries , connective tissue and epithelial cells
what is filtered and transported through the 3 layers to form CSf
blood
CSF is a what substance
protein rich
what is most often due to fx of parietal or temporal bones tearing middle meningeal artery
epidural hematoma
what type of shape is an epidural hematoma
lens
is an epidural hematoma a quick accumulations of blood
yes
what is most often due to venous bleed
subdural hematoma
what type of deterioration is a subdural hematoma
slow , progressive
what type of deterioration is a epidural hematoma
quick
hydrocephalus can be
congenital or acquired
what is an abnormal build up of CSF in the ventricles
hydrocephalus
infants with hydrocephalus that have no fused skulls will have
enlarged heads
children/adults with fused skulls and hydrocephalus will have
excessive pressure especially of white matter
triad of symptoms of children/ adults with hydrocephalus is
worsening gait , incontinence , or cognitive defects
what is it when the ventral system is intact but there is blockage caudal to 4th ventricle
communicating hydrocephalus
what is noncumunicating/ obstructive hydrocephalus
blockage within ventricular system (usually cerebral aqueduct)
what is it called when there is inflammation of the meninges
meningitis
if someone has meningitis when does pain increase
upright position , with head movement , and sneezing and coughing
what is located on the medial side of the homuncules
the lower extremity
what is located on the lateral aspect of the homunclues
face and UE
if there is a blockage inside the circle of willis can the circulation be fixed
yes
what dies the circle of willis form around
optic chiasm and pituitary gland
what artery goes into the medulla
vertebral artery
how much foes the anterior spinal artery supply the sc
> 1/2 of SC
how many arteries supple to anterior and posterior SC
1 from anterior and 2 for posterior
what is it called when arteries connect to abnormal vessels rather than capillaries to veins
arteriovenous malformation
is AVM congenital or acquired
congenital
what are the symptoms of AVM
local pain
is AVM symptomatic or asymptomatic
can be asymptomatic till rupture
where is AVM found
anywhere in the body
what is a thin walled outpouching from artery or vein
aneurysm,
where is an aneurysm found
anywhere in circulatory system
what type of aneurysm is more common
saccular
what is the difference between a saccular and fusiform aneurysm
saccular is one side of a blood vessel and fusiform is both sides of a blood vessel
what is a specialized barrier between capillary endothelium of CNS and extracellular space
blood brain barrier
what is the permeability of the blood brain barrier
less than regular capillaries so large molecules can’t enter
why is it beneficial that the blood brain barrier is less permeable
prevents lots of pathogens from entering CNS
why is it bad that the blood brain barrier is less permeable
prevents certain drugs and proteins antibodies from entering
where is the blood brain barrier absent
parts of hypothalamus and areas close to 3rd and 4th ventricle
what increases form brain stem to vertebral cortices
O2
what is more vulnerable to O2 loss than life centers of brain stem
cortex
cerebral artieres autoregualte local blood flow dependent on what
blood pressure and metabolism
what happens if BP, O2 or pH levels are low or CO2 or lactic acid is high
dilation
what happens if BP, O2 or pH levels are high or CO2 or lactic acid is low
constriction
what is it called when there is excessive fluid in brain tissue
cerebral edema
what are some common causes of cerebral edema
TBI, heart attack or height altitude cerebral edema
why is cerebral edema progressive
bc fluid pressure causes ischemia
what does ischemia causes
arterioles to dilate
what happens when arterioles dilate
increases capillary pressure and permeability
what is it called when there is pressure within the skull
intracranial pressure
how is intracranial pressure measured
by monitor in lateral ventricles
what is the normal range of intracranial pressure
5-15 mm HG
pressure against the flax cerebri is called what brain herniation
cingulate
pressure against the flax cerebri likely to cause what
contractural problems with LE
what brain hernimation is pressure against the midbrain which causes CN 3 dysfunction and loss of consciousness
uncal
what brain hernimation is pressure against the diencephalon moving it , midbrain and pons down
central
which brain hernimation stretches basilar artery with brain stem ischemia/edma
central
which brain hernimation is pressure of cerebellar tonsils putting on brain stem
tonsillar
putting pressure on the brain stem impairs what
consciousness and 4th ventricle
where does the sc and medulla drain into
small veins into radicular veins into epidural venous plexus
where do cerebral veins drain into
dural sinuses into internal jugular veiin
superficial veins drain cortex and neighboring white matter into
superior sagittarius sinus
deep cerebral veins drain basal ganglia, diencephalon, adjacent white matter into
straight sinus
superior sagittarius and straight sinuses meet at
confluence of sinuses
where foes the transverse sinuses arise from and drain into
confluence and internal jugular vein
what stroke is brief localized loss of brain function
transient ischemic attach
how long is a TIA resolved
within 24 hours
is it recommended for a person to seek medical attention with a TIA
yes bc can lead to bigger stroke
what is a brain attack
a stroke
how long does a cerbrovascular accident last
longer than a day
what is an embolus stroke
clot from somewhere else
what is a sudden quick loss of function in a stroke
embolus stroke
what is a thrombus stroke
narrowing and/or clot in area invovled
T/F: a thrombus stroke is gradual worsening or function
true
80% of all strokes are
infarcts (blood being blocked)
what artery does most strokes affects
middle cerebral artery
what is a small deep circulation infarcts
lacunae infarcts
what is a hemorrhage
rupture of a vessel
20% of strokes are
hemorrhage strokes
hemorrhage damage is due to
downstream loss of blood to brain areas
pressure of extra cellular blood accumulation
blood where not supposed to be is irritant to brain tissues
complete blockage of what artery will cause death due to ischemia of brainstorm with vital functions
basilar artery
partial bloackage of the basilar artery can causes
tetrapelgia , numbness, loss of consciousness, cranial nerve damage
what arteries are prone to shear force injuries
vertebral
a stroke in the anterial cerebral artery causes hemiparesis loss to contra lateral side of what body parts
Lower limb
what else changes with a stroke in the anterial cerebral artery
personality changes
a stroke in the middle cerebral artery can causes hemiparesis loss to contractural side of which body parts
face and UE
if there is a stroke in teh middle cerebral artery on the L brain what will be affected
language
is there is a stroke in the middle cerebral artery on the R brain what will be damaged
spatial relationships
neglect
nonverbal communication
what artery supplies the midbrain , diencephalon, hippocampus , thamalus
posterior cerebral artery
if there is a stroke in the posterior cerebral artery what will be damage
eye movements
cortical blindness
what areas are vulnerable to ischemia
watershed areas
