Describe nerve impulse propagation including: Continuous and saltatory conduction Factors affecting impulse speed Encoding stimuli intensities
- Describe nerve impulse propagation including:
- Continuous and saltatory conduction
- Factors affecting impulse speed
- Encoding stimuli intensities
Action potentials are changes in the resting membrane potential that are actively propagated along the membrane of the cell.
• Application of a stimulus diminishes the membrane potential.
• When the membrane potential reaches a critical value lower than the resting level an action potential occurs.
• The membrane potential at which an action potential occurs is called the threshold.
• During an action potential, depolarization can change the membrane potential from –70 mV to about +30 mV. During repolarization, the membrane potential returns to –70 mV.
• The nerve fiber cannot be stimulated again until repolarization is complete. This period is called the refractory period.
• If the stimulus is sufficient to initiate an action potential the entire fiber will fire. This is called the “all or none principle,” for nerve fibers.
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