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20 Cards in this Set
- Front
- Back
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ion channels in neurons
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all formed by transmembrane proteins
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leak (passive) channels
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there are always open and allow for continual ion movement from a higher concentration to a lower concentration
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ligand (chemical) -gated channels
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open and close in response to the binding of a chemical to a receptor in the membrane
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voltage-gated channels
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open and close in response to changes in the membrane potential
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resting membrane potential of neurons
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determined by the concentration of ions.
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potassium K
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inside the cell- high, outside the cell- low
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sodium Na
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inside the cell- low; outside the cell- high
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Anions A
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high potassium and ___ inside the cell
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chloride Cl
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high sodium and ___ outside the cel
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K- potassium
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because of concentration differences, ___ continually leaks out of the cell
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Na- sodium
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because of concentration differences, ___ continually leaks into the cell
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K , Na
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membrane is 25 x more permeable to ___ than ____
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electrochemical attraction
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as inside cell begins to become more negative ____ opposes K movement out of the cell and enhances Na movement into the cell
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Steady state
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membrane stays at -70mv because of the Na/K pump
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polarized neuron
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negative on the inside compared to the positive charge outside
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hyperpolarized
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when neurons become more negative
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depolarized
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when neurons become less negative
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repolarized
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when membrane has been depolarized and it returns to the resting membrane potential
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graded potentials
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small changes in the membrane potential, which occur by the opening of a ligand-gated channels(may be opened by a neurotransmitter) on the dendrites or cell body of a neuron
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5mv
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single graded potential
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