Answer:
Action potentials are generated when information are sent down an axon through the neuron.
Explanation:
Neurons are nerve fibres which uses electrically charged chemicals to bring about an electrical change.
Action potentials can be defined as rapid changes in the membrane potential that spread rapidly along the nerve fiber membrane. Each action potential begins with a sudden change from the normal resting negative membrane potential to a positive potential and then ends with an almost equally rapid change back to the negative potential. The are three stages of action potential, these include:
--> Resting stage: This is the resting membrane potential before the action potential begins. The membrane is said to be 'polarized' during this stage.
--> Depolarisation stage: in this stage, the membrane suddenly becomes very permeable to sodium ions, allowing tremendous numbers of positively charged sodium ions to diffuse to the interior of the axon. That is, the normal polarised state, for example -90 millivolts, is immediately neutralised by the inflowing positively charged sodium ions, with the potential rising rapidly in the positive direction. This is called DEPOLARISATION.
--> Repolarisation stage: This occurs within a few seconds after the membrane becomes highly permeable to sodium ions, the sodium channels begin to close and the potassium channels open more than normal. Then, rapid diffusion of potassium ions to the exterior re- establishes the normal negative resting membrane potential. This is called REPOLARISATION of the membrane.
