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19 Cards in this Set
- Front
- Back
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The action potential changes the membrane potential from ___mV to ___mV and back again to the resting membrane potential.
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-70mV, +30mV
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Action potential results from a change in membrane permeability first to ___ and then to ___ due to the opening of what type of ion channels?
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Na+, K+, voltage-gated
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Where is the density of voltage-gated Na+ channels the greatest?
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Axon hillock
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What areas of the neuron generate signals that open these voltage-gated channels?
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Cell bodies, dendrites
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The opening of voltage-gated channels causes the membrane to ___?
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Depolarize
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If the membrane reaches the trigger point, known as ___ what electrical potential will be generated?
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Threshold, action potential
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During the depolarization phase, voltage-gated ___ channels open and ___ enters the cell.
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Na+, Na+
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What are the two processes that stop the potential from rising above +30mV?
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1) Inactivation of voltage-gated Na+ channels.
2) Opening of voltage-gated K+ channels |
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The opening of voltage-gated K+ channels cause the membrane to ___?
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Repolarize
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When voltage-gated K+ channels open does K+ move into or out of the cell?
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Out of
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If the membrane potential becomes more negative than -70mV, this is called ___?
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Hyperpolarization
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Hyperpolarization is caused by what characteristic of K+ permeability?
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Slow decline
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After an action potential, the neuron cannot generate another action potential because ___ channels are inactivated. This period is called the ___ ___ period.
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Na+, absolute refractory
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During the ___ ___ period, the cell can generate another action potential, but only if the membrane is (more / less) depolarized.
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Relative refractory, more
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Conduction velocity along the axon is increased by what two characteristics?
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1) An increased diameter
2) The presence of myelin |
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Conduction along a myelinated axon is called ___ conduction.
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Saltatory
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Name the disease whose symptoms include loss of vision and increasing muscle weakness.
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Multiple Sclerosis
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What does MS destroy?
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The myelin sheaths of axons
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How does this stop an action potential?
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Too few voltage-gated Na+ channels are between the Nodes of Ranvier.
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