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.