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| The time-dependent opening of ion channels in response to a stimulus, typically membrane depolarization. |
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| The speed at which an action potential is propagated along an axon. |
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| The time-dependent closing of ion channels in response to a stimulus, typically membrane depolarization. |
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The reciprocal of membrane resistance. Changes in membrane conductance result from, and are used to describe, the opening or closing of ion channels.
Closely related to membrane permeability |
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permeability of a membrane to specific ions
Closely related to membrane conductance |
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| the reciprocal of membrane conductance |
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a disease
of the central nervous system
characterized by a variety of clinical
problems that arise from demyelination
and inflammation of axonal pathways. |
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Definition
| The multilaminated wrapping around many axons formed by oligodendrocytes or Schwann cells. |
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| Process by which glial cells (oligodendrocytes or Schwann cells) wrap around axons to form multiple layers of glial cell membrane, thus insulating the axonal membrane and increasing conduction velocity. |
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| Periodic gaps in the myelination of axons where action potentials are generated. |
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| Note that this passive current flow does not require the movement of Na+ along the axon but instead occurs by a shuttling of charge, somewhat similar to what happens when wires passively conduct electricity by transmission of electron charge. |
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| The brief period after the generation of an action potential during which a second action potential is difficult or impossible to elicit. |
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| A process that is self-sustaining. For example, action potential propagation is regenerative because an action potential produced at one location depolarizes downstream regions, thereby activating voltage-gated ion channels to generate an action potential in these regions. |
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Definition
| the reciprocal of conductance |
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Definition
Mechanism of action potential propagation in myelinated axons; so named because action potentials “jump” from one node of Ranvier to the next due to generation of action potentials only at these sites.
This must be a type of conduction |
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Definition
| block K+ currents without affecting Na+ currents. |
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| an alkaloid neurotoxin found in certain puffer fish, tropical frogs, and salamanders, blocks the Na+ current without affecting the K+ current. |
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Term
| voltage clamp method/technique |
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Definition
A technique that uses electronic feedback to simultaneously control the membrane potential of a cell and measure the transmembrane currents that result from the opening and closing of ion channels.
[image] |
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