Term
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Definition
| The first part of an action potential, characterized by a rapid depolarization of the membrane. |
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Definition
| The part of an action potential when the membrane potential is more positive than 0 mV. |
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Definition
| The part of an action potential characterized by a rapid fall of membrane potential from positive to negative. |
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Term
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Definition
| The part of an action potential when the membrane potential is more negative than at rest; also called after-hyperpolarization. |
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Term
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Definition
The hyperpolarization that follows strong depolarization of the membrane;
the last part of an action potential, also called undershoot. |
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Term
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Definition
| A level of depolarization sufficient to trigger an action potential. |
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Term
| absolute refractory period |
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Definition
The period of time, measured from the onset of an action potential, during
which another action potential cannot be triggered. |
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Term
| relative refractory period |
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Definition
| The period of time following an action potential during which more depolarizing current than usual is required to achieve threshold. |
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Term
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Definition
A device that enables an investigator
to hold the membrane potential constant while transmembrane currents are measured. |
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Term
| voltage-gated sodium channel |
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Definition
| A membrane protein forming a pore that is permeable to Na ions and gated by depolarization of the membrane. |
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Term
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Definition
| A method that enables an investigator to hold constant the membrane potential of a patch of membrane while current through a small number of membrane channels is measured. |
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Term
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Definition
| A human genetic disease caused by alterations in the structure and function of ion channels. |
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Term
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Definition
A toxin that blocks Na permeation through voltage-gated sodium channels,
thereby blocking action potentials. |
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Term
| voltage-gated potassium channel |
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Definition
| A membrane protein forming a pore that is permeable to K ions and gated by depolarization of the membrane. |
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Term
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Definition
| The propagation of an action potential down a myelinated axon. |
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Term
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Definition
| A region of the neuronal membrane where action potentials are normally initiated, characterized by a high density of voltage-gated sodium channels. |
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