blood supply to the brain :) Flashcards
cranial meninges layer
dura mater
arachnoid mater
pia mater
dura mater
outer
tough and fiberous
arachnoid mater
projections
spiderweb like
pia mater
delicate and fine layer
what does inflammation of the meninges lead to
meningitis
what are the cranial meninges continuous with
spinal meninges
what does the dura mater consist of
endosteal layer - outer - bound to cranium meningeal layer - inner layer - in contact with arachnoid mater
what are dural folds
inner layer reflects off at certain points
dural folds
falx cerebri
tentorum cerebelli
fall cerebelli
falx cerebri
anterior ot posterior of skull
between cerebral hemispheres
tentorum cerebelli
extends between cerebral hemisphere and celebellum
falx cerebelli
underneath tentorium cerebellli
space between the arachnoid and Pia mater
subarachnoid space
describe the arachnoid mayer
translucent layer that covers brain
provides a smooth surface
fibres from arachnoid to Pia maer
describe pia mater
thin layer adhered to brain extending into every fold of the brain
extradural space
potential (i.e. not in normal anatomy) space between dura mater and crainium
what are embedded in the outer dura mater
meningeal arteries
what does rupture of the meningeal arteries lead to
bleeding into the extradural space
increased intercranial pressure
pressure forces brain down, brainstem herniates into foramen magnum
respiratory arrest and cardiac arrest
what is found in the subarachnoid space
cerebrospinal fluid
arteries/veins to and from brain
what is cerebrospinal fluid
filtrate of blood plasma
what is the subarachnoid space
real (i.e. in normal anatomy)space between the arachnoid and Pia mater
how long does a subarachnoid haemorrhage take to spread
24-48hrs
what are the spaces between the dural folds called
venous sinuses (important in venous drainage of veins)
where do veins empty into
venous sinuses
where do the venous sinuses drain into
ito internal jugular veins
what drain into the venous sinuses
superficial and deep veins drain into sinuses through emissary veins passing through the skull
what do emissary veins allow
potential spread of infection as they run through small forimina
theories of small forimina in the skull??
helps cool blood around the brain
allows blood to pass from Venus sinuses outside the cranium to reduce cranial pressure
where do venous sinuses connect with superficial and deep veins through
orbit
pterygoid venous plexus
pharyngeal venous plexus
emissary veins
where is arterial supply of the brain fro
internal carotid arteries
vertebral artiereis
what are vertebral arteries branches of
subclavian arteries
internal carotid arteries course
goes to underside of cranium through carotid canal then to the brain
course of vertebral arteries
through transverse foramina then through foramen magnum
run either side of medulla, join at pons to form bacillary artiery.
what is the ancillary artier formed from
vertebral arteries
what does the bacillary artier give off
short medullary and pontine arteries (supply pons and medulla)
what does the common carotid artery bifurcate into
internal and external carotid arteries
what type of artieies are the branches of bacillary artery and the internal carotid arties
true end artuers
one artery supplies a specific area where there is no other blood supply
where do the cerebellar artieres arise from
vertebrobasilar system
what do the cerebellar arteries supply
cerebellum
lateral aspects of the brainstem
what does damage to cerebellar arteries results in
cerebellar ataxia (jerky pattern) cranial nerve signs and symptoms (depends on the level of brainstem that is affected CN9 10 11 12)
What causes lateral medullary syndrome
blockage of posterior inferior cerebellar artery or vertebral artier
symptoms of lateral medullary syndrome
cerebellar ataxia
damage to nuclei of CN IX
damage to nuclei of CN X
what does damage of CN IX lead to
dysphagia
no sensation to pharynx
damage of CN X lead to
no sensation/motor to larynx
no motor to pharynx
so no cough reflex, dysphagia, dysphonia
what does the bacillary artery divide into
posterior cerebral arteries
what do the internal carotid arteries divide into
anterior cerebral artery
middle cerebral artery
what do the an/midd/post cerebral artieries supply
hemisphere
what does the anterior cerebral artier supply
thin strip on saggital part
majority of inner surface of brain
what does the middle cerebral artery supply
parietal (leg area of motor/sensory cortex)
temporal
what does the posterior cerebral artery supply
occipital (i.e. visual cortex)
underneath
what is brocas area linked to
speech motor area
unable to speak what they are thinking
wernikes area
interpretation and understanding of speed
speech makes no sense but can speak
what supplies brocas/wernikes area
middle cerebral arteriy
what can disease/damage to arteries supplying the brain lead to
stroke
types of stroke
ischemic stroke
haemorrhagic stroke
what causes an ischemic stroke
due to a blood clot that blocks the flow of blood
what causes a haemorrhage stroke
burst blood vessel (aneurysm) or due to drama (tearing) leading to blood leaking into the tissue
effects of isemic stroke
brain function lost were blood supply is germanely absent
effects of harmorrhagic stroke
short term effects worse
mass of hematoma decreases over time, function may return
where does the brain receive blood supply from
vertebral bacilar artery
carotid arteries
circle of willis
internal carotid arteries and vertebasilar system joined via communicating arteries - cn act as alternative blood supply if blood vessels damaged
what do the anterior communicating artieries join t
the two sides of the carotid arteries
what do the posterior communicating arteries join
cerebral and bacillary artieries
