Term
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Definition
nNormally have 55 ml of blood flowing through every 100 grams of CNS per minute
nIf event occurs and only 20 ml/100g/min = neuronal electrical activity stops
nIf event occurs and only 10 ml/100g/min for several minutes = necrosis of tissue/infarct
qStrokes; neurons have died
nMinutes?……..irreversible damage
qBecause you need constant blood supply to brain
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Term
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Definition
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nCells are highly selective.
nBlood brain barrier in better detail: arterial framework of brain includes a membrane of outer artery is like mesh so doesn’t allow things to get in, so nothing can escape into brain tissue or get in
nRestricted exchange of molecules from blood into cells of the NS
nExcludes many drugs from the CNS
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Term
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Definition
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nCarotid system
nVertebral system
nSystem makes a number of 90 degree turns to not overwhelm the system/slows flow!
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Term
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Definition
nInternal carotid arteries:
qTelencephalon
qDiencephalon
à aka majority of cerebrum
nVertebral arteries:
qBrainstem
qCerebellum
qSpinal cord
qOccipital lobes
qTemporal lobes
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Term
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Definition
nInternal and external carotids
qInternal up through neck and foramen and branch R/L
qOpthalmic arteries to retina
qAnterior cerebral arteries (ACA) - medial aspects of both hemispheres
qMiddle cerebral arteries (MCA)- language cortex
qPosterior communicating arteries (Pcomm) to connect to posterior system/vertebral
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Term
ICA (INTERNAL CAROTID ARTERY) & ACA (ANTERIOR COMMUNICATING) |
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Definition
nACA (anterior communicating artery): travels up the longitudinal fissure to supply the frontal lobe, olfactory bulb, supplementary motor area, primary somatosensory area, primary motor area
qLesions result in: (depending on where embolus falls)
nContralateral (opposite side) hemiparesis and sensory loss Lower Extremity>Upper Extremity
nAphasia
nApraxia
nCognitive changes- because frontal part of brain
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Term
ICA & MCA (MIDDLE CEREBRAL ARTERY) |
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Definition
nMCA (middle cerebral artery): travel along lateral sulcus to supply most of the hemisphere including primary motor cortex, premotor cortex, primary somatosensory area and language areas
qLesion:
nContralateral hemiparesis and sensory loss UE and face>LE
nHomonymous hemianopsia (can see out of half of eye)
nAphasia if dominant hemisphere affected
nAttention, memory, visual-spatial deficits, neglect if non-dominant hemisphere
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Term
ICA & PCOMM (POSTERIOR COMMUNICATING ARTERIES) |
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Definition
nPcomm (posterior communicating arteries): pair that join the ICA with the PCA in each hemisphere
qLesion
nDeficits in functions of the optic chiasm, thalamus, hypothalamus
nNot a common area of infarct
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Term
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Definition
nVertebral arteries R/L
nForm ONE basilar artery (anastomosis)
qSeparate into ** two posterior cerebral arteries (PCA)
qImportant for brainstem! And cerebellum!
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Term
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Definition
nEnter the subarachnoid space through the foramen magnum; 3 branches which collectively supply the medulla à then form basilar
qLesion to vertebral arteries
nDecreased consciousness
nNausea and vertigo
nGait ataxia and impaired balance
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Term
ASA (ANTERIOR SPINAL ARTERY) |
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Definition
nAnterior spinal artery supplies the anterior 2/3 of spinal cord
qLesion=anterior cord syndrome
nImpaired or absent pain, temperature, and motor function
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Term
PSA (POSTERIOR SPINAL ARTERY) |
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Definition
nPosterior spinal artery supplies the posterior 1/3 of cord
qLesion=posterior cord syndrome
nAbsent proprioception, vibraion, two pint discrimnation and asterognosis
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Term
PICA (POSTERIOR INFERIOR CEREBELLAR ARTERY) |
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Definition
nPosterior inferior cerebellar artery supplies dorso-lateral region of medulla, inferior cerebellum, and choroid plexus of the 4th ventricle
qLesion
nVertigo, vomiting, ataxia
nBrainstem dysfunction
nContralateral loss of pain and temperature
nIpsilateral Horner’s syndrome (contraction of the pupil, ptosis, recession of eyelid into orbit)
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Term
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Definition
nFormed by union of vertebral arteries near the pontomedullary junction supplies the pons and most of the cerebellum
qLesion
nDeath if complete occlusion
nPartial occlusion =tetraplegia, loss of sensation, coma, cranial nerve deficits
nAcute cerebellar infarct = dizzy, nausea, dysarthria, headache
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Term
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Definition
nAnterior Inferior Cerebellar Artery supplies cortex of the inferior surface of cerebellum, upper medulla, and pons
nSuperior Cerebellar artery supplies cortex of the cerebellum, medulalary center, pons, and superior cerebellar peduncles
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Term
PCA (POSTERIOR CEREBRAL ARTERY) |
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Definition
nPosterior Cerebral Artery R/L formed by division of the basilar artery at the junction of the pons and midbrain. Primary blood supply to the midbrain, occipital lobe, part of the inferior and medial temporal lobes, hippocampus, thalamus, choroid plexus
qLesion
nContralateral hemiparesis
nParesis/paralysis of eye movements
nCortical blindness
nDeclarative memory problems
nThalamic syndrome- sensory relay- severe pain, contralateral hemisensory loss, and flaccid hemiparesis
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Term
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Definition
n Connecting arteries w/ Collateral flow
n Anastamosis site of joining together
n Connect carotid and vertebral systems
n At base of brain above brainstem above point where posterior commisural arteries come together
n Acomm (anterior communicating artery): connet internal carotid artery
n Pcomm (posterior communicating artery): connect basilar system up to the carotid
n Safety net for disrupted blood supply if the lesion is below the circle
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Term
TRANSIENT ISCHEMIC ATTACK (TIA) |
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Definition
nPredictor of CVA (cerebrovascular accident stroke)
q10% of all CVA’s start with TIA
qTIA= disruption of blood supply, stroke symptoms, resolved within 24 hours
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nCauses:
qFast food, smoke, drink
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Term
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Definition
nIschemic
q85-95% of all CVA’s
qThrombosis: narrowing of artery bc of plaque or fat
qEmbolis: traveling blood clot
nWithin ONE artery
qLack of perfusion not enough bloodflow to brain
nHemorrhagic- bleed
q5-15% of all CVA’s
qIntracerebral hemorrhage: ICH
qSubarachnoid hemorrhage: SAH
nHappens in arachnoid space which is a meningeal layer with dura and pia
nAneurysm
qExcessive bloodflow to brain
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Term
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Definition
nThrombus
nEmbolus
nSystemic hypoperfusion: watershed strokes, not enough blood pressure to deliver to all organs
qAffects more than 1 artery; whole arterial system
TREATMENT:
nBlood thinners or baby aspirin; Heparin (IV) or Coumadin (pill form)
nTPA= tissue plasminogen activator given if arrive quickly enough when not hemorrhagic and slightly ischemic to reactivate blood supply and get to infarcted tissue
nAnticoagulants: anti-clot drugs
nCarotid endarterectomy: removal of thrombus
nCerebral angioplasty: roto-router blast artery to break up plaque
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Term
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Definition
nIntracerebral hemorrhage (ICH)
nSubarachnoid hemorrhage (SAH)
n
qTOO MUCH BLOOD! ARTERY RUPTURES!
TREATMENT
nCraniotomy: remove skull and drain out blood
nClipping: aneurysm to stop swelling
nCoiling: coil the artery with a sheath to stop swelling
nDrainage: catheter draining
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Term
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Definition
qHemiplegia: weakness on one side
qNumbness: unilateral
qSensory changes: unilateral “can’t feel with right hand”
nBrainstem
qVision changes
qFacial or lingual weakness
qDysphagia or dysarthria: trouble swallowing
nCortex
qAphasia
qApraxia
qNeglect
qDysarthria
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