... forming just inside the neurone, there is also an EQUAL build up of positive charges on the outside of the neurone. The RMP is measured in millivolts (mV) and typically lies between -40 and -90 mV. The RMP arises from differences in the ion concentrations between the cell (neurone) and the extracellular fluid. Outside the cell = , Inside the cell = The membrane is 100 times more permeable to than it is to therefore the fluid that is next to the inner surface of the neurone becomes more negative as the leaves. Action Potential (aka nerve impulse) A stimulus of sufficient size will change the membrane potential to the critical level, this will then lead to the threshold potential - this is the potential at which a response is produced. this threshold potential then triggers a rapid and continuously increasing depolarisation until it become briefly positive inside this is the action potential and continues ...

See this essay or coursework document in full right now