What are the electrical changes in an axon that occur during an Action Potential?

• The resting potential of the axon membrane is around -70mV, where it is more negative on the outside of the axon than the inside.

• A stimulation causes Na+ (sodium ions) channels in the axon membrane to open and Na+ ions move out of the membrane by facilitated diffusion.

• If the stimulation is reached then the axon membrane will depolarise to +30mV. Na+ ion channels close.

• K+ (potassium ions) channels open to allow diffusion of these ions (repolarisation).

(I always find it useful to write my answers to questions like these in step-by-step bullet points. This makes it easier to keep the answer logical and coherent. It is important to include the keywords for the topic, i.e. depolarisation and repolarisation.)