How is an Action Potential produced in a neurone?

It is all to do with the movement of ions in and out of the neurone cell, which changes the potential difference accross the cell's membrane. 

- In a neurone's resting state, the inside of membrane is more negative than the outside of the membrane. It has a RESTING MEMBRANE POTENTIAL of -70mV

1) A stimulus excites the neurone. 

2) This causes sodium channels in the membrane to open. Positive sodium channel diffuse INTO the neurone down a concentration gradient. 

3) Due to the influx of positive ions, the membane potential becomes LESS NEGATIVE. This is called depolarisation. 

4) At a membrane potential of around +40mV, sodium channels close and potassium channels open. Positive potassium ions diffuse OUT of the neurone. The membrane potential becomes MORE NEGATIVE again untill it reaches the resting poteneial of -70mV. 

This sequence of events is called an ACTION POTENTIAL.