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26 Cards in this Set
- Front
- Back
What are the two things required for brian function?
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glucose
oxygen |
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What is rate limiting step in glycolysis?
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hexokinase and G6P
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After G6P is made what hapepns to it?
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1)it can go through glycolysis
2)it can become glycogen 3) it can enter the pentose shunt |
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Where does most og G6P end up going?
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90% to glyclolysis, 5% to glycogen, 5% to pentose shunt
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What is the rate limiting enzyme in the TCA cycle
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pyruvate dehydrogenase
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What regulates byruvate dehydrogenase?
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ATP/ADP and Ca levels
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What does the citric acid cycle also produce besides ATP
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amino acids/neurotransmitters
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Does aerobic metabolism of brain use its fair share of oxygen consumed by body?
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no it uses way more
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What is the relationship between astrocytes and neurons in terms of lactate shuttle?
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1)astrocytes take up glucose by facilitated diffusion and convert it to lactate
3)lactate goes into neurons 4) lactate goes back to pyruvate and goes to TCA cycle |
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what stores most of glygocen in brain?
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astrocytes
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What is the link between increased activity and astrocytes?
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1)increased neuronal activity means more glutamate
2) glutamate taking up by astrocytes and converted to glutamine 3)glutamine stimulates Na/K ATPase 4) glycolysis in astrocytes is driven forward |
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What are teh changes during the prenatal period?
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becomes ketotic at birth in response to high fat in moms milk and brain is hypoglycemic
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What are changes in child hood?
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different rates for different parts of brain going
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What are the age related differences in blood flow and oxygen consumption between 21 and 71
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no difference
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What are age related diseases that can cause metabolic disruption?
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vasculature and neurodegenerative diseases such as ateriosclerosis and snile psychosis
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What happens to the brain in hypoglycemia?
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confusion or lack of consciousness
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What causes hypoglycemia in brain?
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usually hyperinsuliemia
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What are conditions that present with hyperglycemia?
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1)liver failure
2) fatty acid oxidation deficiency and fasting 3) genetic abnormalities of glucose transport in BBB |
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What is ischemia caused by?
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1) stroke
2) trauma 3) edema 4) cardiac arrest |
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What is the mechanism of ischemia?
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1)loss of ATP production
2) ion pumps fail 3) cell depolarized 4) Ca channels open 5) Ca activates proteases for cell death |
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What are effects of hypoxia/ischemia on nearby tissues?
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1)accumulated lactate causes tissue acidosis
2)spreading depression 3)excitotoxicity |
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What is spreading toxcicity?
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dying neurons release K into ECM which depolarizes neurons outside the effected area
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How does excitotoxicity happen in ischemia?
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excess glutamate activates NMDA receptors and opens Ca channels in adjacent tissues
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What are the regions of brain susceptable to ischemia?
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1)hippocampus Ca1
2)frontal corrtex 3) amygdyla 4) straitum 5) thalamus |
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What is an effective treatment?
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tissue plasminogen activating factor
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What is the problem with reperfusion treatment
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it does not always work because of vasospasm etc
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