Describe the process of an action potential through a neuron

A stimulus (e.g. change in temperature, pain, etc.) results in the depolarisation of the membrane of the neuronal cell body. This depolarisation causes the membrane potential to rise from resting potential (-70mV) to a threshold poential (-55mV). At the threshold potential, voltage-gated sodium ion channels will open. This results in a influx of sodium ions into the cell which causes the membrane to depolarise and open neighbouring voltage-gated sodium ion channels further along the membrane, consquently initiating an action potential along the neuron (like a domino effect). Once a threshold has been reached (about +40mV), sodium ion channels will close and potassium ion channels will open, allowing an efflux of potassium ions and causing the neuron to repolarise back to a negative membrane potential. There is a brief period of hyperpolarisation due to the action of leaky potassium channels. Sodium pumps (Na+/K+ pumps) will actively transport 3 sodium ions out and 2 potassium ions in to bring the membrane potential back to resting potential.