Initiation of impulse at muscle

1] An impulse from a nerve causes calcium to enter a synaptic end bulb.

2] Acetycholine is released and diffuses across the cleft between the nerve and the muscle cell.

3] Two molecules of Acetycholine bind with receptors on the muscle cell membranes.
This opens the sodium channel gate.

4] Sodium flows into the cell.

5] The cell is depolarised.

6] Muscle action potential is generated, causing the muscle to contract.

7] Acetycholine is broken down into choline and acetate and returns to the synaptic end bulb
to recombine.

8] The sodium channel closes and the potassium channel opens.

9] The cell now repolarises.

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