The Action Potential

THE ACTION POTENTIAL

STAGE ONE

• 
• At resting state, the inside of the cell is negatively charged and the outside surrounding the cell is positively charged.

STAGE TWO

• 
• When the neurone is sufficiently activated by a stimulus, the cell gradually becomes positively charged in a process known as depolarisation.

STAGE THREE

• 
• As an impulse passes through the neurone, it gradually switches the charges.

STAGE FOUR

• 
• The action potential travels down the axon towards the terminal buttons in a process known as firing. Since the impulse is moving, the charges of the previous sections switch back to their original state.

STAGE FIVE

• 
• The action potential is an 'All-or-Nothing' event, meaning the impulse must travel all the way through the neurone, or not at all. If depolarisation doesn't reach a certain threshold, then there can be no action potential.