Neurovasculature Flashcards
what are the two main divisions of neurovasculature
Carotid circulation
Vertebrobasilar circulation (aka vertebral-basilar system)
what does the brain need?
great deal of oxygen and glucose from the blood
4 major arteries supplying majority of CNS from heart
yes,
2 vertebrals
2 IC
why is it important to have 4 major supplies to the CNS from the heart?
important because if 1 or 2 gets occluded, can still get enough blood to brain to survive and do ok
can survive on 2 of them
ascends from the left ventricle of the heart
aorta
arise from the aorta and subclavian arteries
CC and vertebral arteries
anterior supply
carotid
posterior supply of blood to the head
vertebral
branch off from the subclavian arteries and provide about 20% of the blood supply to the CNS
vertebral arteries
blood supply brainstem, cerebellum, parts of the diencephalon, spinal cord, occipital and temporal lobes
vertebral
blood to brain, eyes, etc
internal carotid
blood to face and mouth
external carotid
~80% of the blood supply to the telencephalon and diencephalon
internal carotid arteries
supplies areas of the cerebellum, medulla and choroid plexus of the 4th ventricle
Posterior inferior cerebellar arteries
spinal cord (posterior side)
2
Posterior spinal arteries
anterior SC
single one
Anterior spinal artery
is one va larger than the other?
yes, the left is
supply inferior portion of cerebellum including the flocculus
Anterior inferior cerebellar arteries
supply superior cerebellum, much of the caudal midbrain and rostral pons
Superior cerebellar arteries (SiCA)
supply caudal diencephalon, medial occipital lobe and inferior temporal lobe
at the level of the midbrain—posterior cerebral arteries
arteries around to back of pons and Anterior Inferior Cerebellar a. to Cochlear Nuculeus
circumferential
supply SOC into pons tissue
Penetrating arteries
supply to Inferior Colliculus and some MGB at pons
Superior Cerebellar a. and Posterior Cerebral a
directly from basilar artery or from anterior inferior cerebellar artery
Internal auditory or labyrinthine arteries
Begins at upper border of the thyroid cartilage and ascends to reach the base of the skull
internal carotid
Enters at the carotid canal (aka lacerum)
internal carotid
what branches off of the IC and divides into the many branches
opthalamic artery
gives rise to middle cerebral arteries and anterior cerebral arteries, as well as posterior communicating arteries (More with Circle of Willis)
internal carotid
arises opposite the upper border of the thyroid cartilage, inclines backwards to space between the neck and condyle of the lower jaw and the external auditory meatus
external carotid
Divides into temporal and internal maxillary arteries
external carotid
Branches—supply the neck, face and base of skull
external carotid
what is our safety valve?
circle of willis
provides main blood supply to the lateral surface of cerebral hemispheres.
Middle cerebral artery
supply the superior, posterior and inferior borders.
supply the medial portion of the cerebral hemispheres.
Anterior and posterior cerebral arteries s
supply the temporal lobe.
Middle and posterior cerebral arteries
what is a water shed area?
one artery ends and the next picks up
blood supply midline of longitudinal fissure
anterior cerebral artery
blood supply of midline of temporal lobe
posterior cerebral artyer
blood supply around the lateral fissure
middle cerebral artery
anastomosis
interconnections
why do we have the circle of willis? How is it made?
signs of a stroke
B = Balance: Sudden loss of balance
E = Eyes: Loss of vision in one or both eyes
F = Face: Face droops on one side
A = Arms: Arm drops when both arms are raised
S = Speech: Speech is slurred or sounds different
T = Time: Time to get help immediately
do we always know what causes SNHL?
no, evidence that ~40% maybe from vascular deficits
decusations of pyramid
go across the two sides of medulla
olives
bulges on side of medulla
what is angiography
medical imaging technique used to visualize the inside, or lumen, of blood vessels and organs of the body, with particular interest in the arteries, veins, and the heart chambers
cavities formed by the endosteal and meningeal layers of the dura mater
venous sinuses
all sinuses join together and dump out into
the jugular vein
abnormalities with blood supply
Degrees of variation or normal in neurovasculature
Vascular plasticity
Reorganization of blood flow due to longstanding atherosclerotic disease
what makes the plasticity in our blood supply?
circle of willis
weakened arterial walls that balloon (look like berries) and can rupture and cause intracranial bleeding
berry aneurysms
a large network of blood vessels
plexus
large amounts of blood escapes into surrounding tissues without clotting
hemorrhage
small amounts of blood that escape into surrounding tissues causing bruising
hematoma
a foreign body (blood clot) that travels within the body and can constrict blood flow
embolus
a blood clot, a lesion attached to the inner vessel wall, can block partially or fully the flow of blood.
thrombus
most common cause of neurological deficits
Cerebrovascular disease and accidents
what can cause malfunction and death of neurons
reduction in blood flow
necrotic region of tissue
infarct
abrupt incident of vascular insufficiency
stroke
loss of blood supply due to mechanical blockage
ischemic stroke
blood clot within a vessel (attached)
thrombus
a bit of foreign matter, such as a blood clot or atherosclerotic plaque carried in the bloodstream (could be detached thrombus)
embolus
minutes to hours, usually from an emboli that is broken down
transient ischemic stroke (mini stroke)
a localized mass of blood outside of blood vessels that is relatively or completely confined within an organ or tissue, a space or potential space; the blood is usually clotted.
Hematoma
an escape of blood through ruptured or unruptured vessel walls
Hemorrhage
what can have symptoms like a stroke?
Hemorrhages
where would damage be more dangerous?
more dangerous becasue BS has a lot of life manageing functions (automatic things) and can go into a coma with life threatening
supra could just affect a little of something
what can cause neurovasculature damage?
hemmorrhages
Small arteries may rupture
Spontaneously—increased chance with hypertension
localized dilation of a blood vessel
aneurysm
an aneurysm is
subarachnoid hemorrhage
classically occur where cerebral arteries branch off of the circle of Willis
berry aneurysm
Arteriovenous malformations
Arteries and veins tangle together and blood is shunted from arteries to the veins
Delicate walls may lead to intracerebral hemorrhages
Caused during development
Can enlarge with age and can result in stealing of blood from areas or hemorrhaging
symptoms of AVM
Seizures
Headache or pain in one area of the head
Muscle weakness or numbness in one part of the body
Severe headache
Weakness, numbness or paralysis
Vision loss
Difficulty speaking
Confusion or inability to understand others
Severe unsteadiness
blood brain barrier
helps to protect our CNS
tight junctions of the endothelial cells that line the capillaries in the CNS
Stopping most macromolecules from entering or leaving the CNS
Lipid-soluble substances and glucose can cross
blood CSF barrier
macromolecules can reach the choroid plexus but the capillaries do not come in direct contact with CSF so there is a barrier
arachnoifd barrier layer
arachnoid cells tightly zipped together with tight junctions to stop diffusion between the subarachnoid space and the extracellular fluids of the dura mater
ones something enters that subarachnoid space, it will stay until sucked into arachnoid villa into venus sinous
CSF-Brain interface
CSF bathes the brain and there are not cells with tight junctions so macromolecules move freely between the CSF and intercellular spaces
what makes up circle of willis?
posterior communicating arteries (2)
Anterior communicating artery (1)
connected carotid and V-B vasculature