Medical Definition of antioxidant. : any of various substances (as beta-carotene, vitamin C, and alpha-tocopherol) that inhibit oxidation or reactions promoted by oxygen and peroxides and that include many held to protect the living body from the deleterious effects of free radicals.
An action potential is a very rapid change in membrane potential that occurs when a nerve cell membrane is stimulated. Specifically, the membrane potential goes from the resting potential (typically -70 mV) to some positive value (typically about +30 mV) in a very short period of time (just a few milliseconds).
Best Answer: An action potential is an electrical signal that travels from one part of a nerve cell to another. The action potential begins at the soma or cell body. It then travels down the axon (this might be as long as 1 meter in some cases). At the nerve terminal (the end of the axon), the action potential stops. But, it triggers a chemical signal (neurotransmitter) to be released across the synapse (the gap between two nerve cells or a nerve cell and a muscle cell).