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18 Cards in this Set
- Front
- Back
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what does polarized mean?
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that there is a difference between two areas that are being compared.
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what is depolarization?
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the process of removing the differences
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what does depolarized mean?
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there is no difference between the two areas being compared
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what is repolarization?
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the process of re-establishing the original differences
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what is a nerve impulse?
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a series of action potentials that occur on an axon one right after another and creates a dominino effect
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what is an action potential?
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a measuring of voltage at one place on an axon at any given time
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when a neuron is at rest?
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called a polarized cell membrane
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the difference of charged particles (ions/electrons) is measured by what?
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volts, also means a seperation of charges
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cell membrane of neuron at rest?
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positive charge of Na on outside of membrane and negative charge of K on inside
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concentration of neuron at rest?
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higher concentration of Na on outside than on the inside. higher concentration of K on inside of membrane than on the outside
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what happens when an impulse occurs?
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depolarization
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1st step of depolarization
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set of slow Na channels open allow Na to slowly diffuse into the axon and voltage slowly rises
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2nd step of depolarization
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at threshold another set of Na channels open, and the NA diffuses rapidly and the voltage rises quickly
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3rd step of depolarization
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a set of K channels open and K rapidly diffues out of the axon and the voltage drops to below it's resting place
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before an axon can carry another impulse what must it do?
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repolarize
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what does repolarization require?
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the action of Na/K pumps in the axons membrane
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"4th" step
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the pumps will pump sodium ions out of the axon and potassium ions into the axon bringing it pack to polarized condition
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what do the Na/K pump require?
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energy from ATP. One ATP is burned, two K ions get pumped in and three NA ions get pumped out
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