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31 Cards in this Set
- Front
- Back
What 2 minor substrates can be used in absence of glucose by neurons?
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Beta Hydroxybutyrate
Glutamine |
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What does increased electrical stim. do to the metabolic requirements of neurons?
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increases it
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What has a higher metabolic requirement, white or gray matter?
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gray matter
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How long can axons survive ischemia?
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45 min
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Does BP over the usual physiologic range determine CBF?
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No
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How low does SBP have to get before acute changes in CBF will be seen?
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<50mmHg
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What determines changes in CBF in normal individuals?
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Metabolic demand
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What are the units of CBF?
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cc/100gm tissue/min
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What is the lower limit of CBF needed to support normal function?
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20cc/100gm tissue/min
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What is the lower limit of CBF to allow neuronal viability but not normal fxn?
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10cc/100 gm tissue/min
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1 minute of ischemia =
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5 min. severe hypoglycemia
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1 minute of hypoglycemia =
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5 min severe status epilepticus
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High concentrations of what AA can produce an influx of Ca++ that will destroy neuronal fxn?
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glutamate
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CBF =
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CPP/R
(R is at the arterioles) |
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CPP =
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MAP - ICP
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What happens to CPP when ICP increases?
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The pressure differential driving blood into the brain is reduced, so CPP is REDUCED
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What is the pathology of hemorrhagic stroke?
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injury is due to direct compression of neurons and secondarily to decreased blood flow from increased ICP?
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Of what nature are the majority of strokes?
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Ischemic (embolic or thrombotic)
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Which kind of stroke is most likely to produce severe, rapid debilitation?
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hemorrhagic stroke
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What kind of ischemic stroke is rapid with onset and having deficit maximal at its outset and has a higher risk of hemorrhage?
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Embolic Stroke
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Which kind of stroke has a stuttering course and can involve the carotid artery or smaller vessels in which it may produce lacunar strokes?
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Thrombotic Stroke
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Upon event in the right cerebral hemisphere, which artery is involved in arm and facial deficits moreso than the leg on the left side?
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MCA
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Which artery is involved in events causing deficits in the contralateral leg that are greater than that affecting the arm and face?
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ACA
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What deficit is usually more prominent with right cerebral cortical strokes than primary sensory loss?
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left hemineglect
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Why is left visual field deficit not common in right cerebral strokes?
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because the occipital cortex is primarily supplied by the PCA
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What happens to gaze preference in stroke occuring in one side of cerebrum?
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gaze will go to side of lesion
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Strokes on which side of the cerebrum are particular for constructional apraxia, topographic deficits and confabulation?
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right sided
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Stroke on which side of the cerebrum will elicit sx of apraxia, acalculia, finger agnosia, and right - left confusion?
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left sided
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If a patient presents with a visual field cut, memory loss, or alexia, which artery distribution could possibly be affected?
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PCA
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Which sx of being unable to read is a sx of a defect in the PCA distributiion of the left side?
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Alexia
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What are the hallmark signs of a brainstem stroke?
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crossed signs
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