What are the steps contained in action potential production?

The first step of the production of an action potential is a stimulus, which is a signal that excites the cell membrane causing Na+ ion channels to open. These channels are called voltage gated ion channels as it depends on the electrical membrane potential across the cell membrane. The opening of the channels means the membrane is more permeable to Na+ so Na+ ions diffuse into the neurone down their concentration gradient, as there is a higher concentration of Na+ ions outside than inside the cell. The inside becomes less negative as a result.If the potential difference created reaches a threshold potential, which is the level needs for a stimulus creating the generator potential to reach, the Na+ ion channels open and more Na+ diffuses into the neurone. This is known as depolarisation.The inside of the neurone becomes less negative to a point of around +30mV, where the Na+ ion channels close and the voltage-gated K+ ions open. K+ ions diffuse out of the neurone down their concentration gradient as there is more K+ inside than outside the neurone. This brings the membrane potential back down to the resting potential, the process is called repolarisation.However, hyperpolarisation can occur where K+ ion channels are too slow to close and too many K+ ions diffuse out of the neurone, so the potential difference is lower than the resting potential.Finally, the resting potential is restored as the ion channels are reset, the sodium-potassium pump returns membrane to its resting potential by pumping Na+ out and K+ in.