Term
| action potential aka spike or impulse |
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Definition
| The electrical signal generated and conducted along axons (or muscle fibers) by which information is conveyed from one place to another in the nervous system (or within muscle fibers). |
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Definition
| Transmembrane proteins that actively move ions into or out of cells against their concentration gradients. Their source of energy may be ATP or the electrochemical gradients of various ions. See also co-transporters; ion exchangers. |
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Definition
| Displacement of a cell’s membrane potential toward a less negative value. |
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Term
| electrochemical equilibrium |
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Definition
The condition in which no net ionic flux occurs across a membrane because ion concentration gradients and opposing transmembrane potentials are in exact balance.
Electrochemical equilibrium occurs when there is an exact balance between 2 opposing forces: (1) the concentration gradient that causes K+ to move from inside to outside, taking along positive charge, and (2) an opposing electrical gradient that increasingly tends to stop K+ from moving across the membrane. |
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Definition
| The membrane potential at which a given ion is in electrochemical equilibrium. |
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Definition
the phase during which the membrane potential rapidly repolarizes
[image] |
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Definition
Mathematical formula that permits membrane potential to be calculated for case where a membrane is permeable to multiple ions.
[image] |
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Definition
| The displacement of a cell’s membrane potential toward a more negative value. |
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Definition
| Integral membrane proteins possessing pores that allow only certain ions to diffuse across cell membranes, thereby conferring selective ionic permeability. |
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Definition
A mathematical formula that predicts the electrical potential generated ionically across a membrane at electrochemical equilibrium.
[image]
R, ideal gas constant: 8.314 J/mol-K
T, absolute temperature, K: room temperature ≡ 20°C (for these experiments)= (273+20) = 293K
F, Faraday constant, magnitude of electric charge per mole of electrons. 96,485.33 C/mol
NOTE: 1 Joule = 1 Volt X 1 Coulomb |
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Definition
| The peak, positive-going phase of an action potential, caused by high membrane permeability to a cation such as Na+ or Ca2+.
[image] |
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Term
| passive electrical responses |
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Definition
| Responses to applied electrical currents that do not require activation of voltage-gated ion channels. |
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Definition
| The membrane potential change elicited in receptor neurons during sensory transduction. Also called generator potentials. Compare synaptic potential. |
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Term
| resting membrane potential |
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Definition
| The inside-negative electrical potential that is normally recorded across all cell membranes. |
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Definition
| The initial, depolarizing, phase of an action potential, caused by the regenerative, voltage-dependent influx of a cation such as Na+ or Ca2+.
[image] |
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Definition
| A membrane potential change (or a conductance change) generated by the action of a chemical transmitter agent. Synaptic potentials allow the transmission of information from one neuron to another. Compare receptor potential. |
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Definition
| The level of membrane potential at which an action potential is generated. |
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Definition
| The final, hyperpolarizing phase of an action potential, typically caused by the voltage-dependent efflux of a cation such as K+.
[image] |
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