Term
|
Definition
Rapid large depolarization is used for communication
Action potentials travel along axons from the cell body to the axon terminal (or if an afferent neuron, from the receptor to the terminal) |
|
|
Term
|
Definition
| Minimum depolarization necessary to induce the regenerative mechanism for the opening of sodium channels |
|
|
Term
|
Definition
•Two gates are associated with the channel
Activation gate and inactivation gate |
|
|
Term
|
Definition
•Voltage dependent
•Opens at threshold and depolarization
•Positive feedback |
|
|
Term
|
Definition
Voltage and time dependent
•Opens during depolarization
•Closes during depolarization |
|
|
Term
|
Definition
•Threshold
–Minimum depolarization necessary to induce the regenerative mechanism for the opening of sodium channels
•Threshold depolarization action potential
•Subthreshold depolarization no action potential
•Suprathreshold depolarization action potential
•Action potentials from threshold and supra-threshold stimuli are the same magnitude
–100 mV (–70 mV +30 mV) |
|
|
Term
| Absolute Refractory Period |
|
Definition
–Spans all of depolarization and most of the repolarization phase
–Second action potential cannot be generated
–Na+ gates are inactivated |
|
|
Term
| Relative Refractory Period |
|
Definition
–Spans the last part of the repolarization phase and hyperpolarization
–Second action potential can be generated—with a stronger stimulus
–Some Na+ gates are closed; some are inactivated |
|
|
