Action Potential Research Paper
The threshold is generated when the membrane of the cell is depolarize around -50mv to evoke the action to occur. Action potential is all or none because is either no action potential or a full amplitude of action potential. We say that action potential is regenerative since a new action potential is generated at each location along the cell membrane. The saltatory conduction occurs on axons with myelin sheaths and in the Nodes of Ranvier. Each action potential have a refractory period, where at the place the action potential occurs in the cell membrane, there is a brief period of time (about 10ms) where is impossible to make another action potential to occurs in the same area of the membrane.
In order to have an action potential, ion channels have to be present and available in the cell membrane, and caused by a stimulus, let explain the functions. When there is no action potential, the membrane ions of K+ (potassium) and Na+ (sodium) probability to open are low, the ion channels are close. To reach threshold, the Na+ channels become more permeable therefore open and Na+ flows into the cell membrane. The influx of Na+ ions causes a depolarization in the cell. If the depolarization causes enough change in the cell membrane electrical potential from around -70mV to about -50mV, the action potential will be generated and the probability of Na+ channels to be open will increase. The charge inside the cell becomes more positive. Once above the threshold, Na+ current is greater and stronger than K+ current, causing the depolarization, which opens more voltage-gated ion channels