Outline how nerve impulses are transmitted along a nerve fibre.
1. Sodium (voltage-gated) channels open and Na+ diffuse into neuron (down concentration gradient).
2. Inside of neuron becomes positive compared to the outside, so potential is reversed = depolarization.
3. Wave of depolarization moves down the membrane.
4. Potassium channels open and K+ diffuse out down the concentration gradient.
5. Inside becomes negative compared with outside, potential across membrane restored = repolarization.
6. Active transport K+ (into neuron) and Na+ (out of neuron) restores resting potential.
PW
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