addiction: The National Institute of Drug Abuse defines this as a complex chronic disease that is “characterized by drug seeking and use that is compulsive, or difficult to control, despite harmful consequences.” A first exposure to drugs is usually voluntary. But repeated use of certain drugs, NIDA explains, can create changes in the brain that make it hard “to resist intense urges to take drugs.”
cell: (in biology) The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall. Depending on their size, animals are made of anywhere from thousands to trillions of cells. Most organisms, such as yeasts, molds, bacteria and some algae, are composed of only one cell.
depression: A low spot, such as in a field or the surface of a rock. (in medicine) A mental illness characterized by persistent sadness and apathy. Although these feelings can be triggered by events, such as the death of a loved one or the move to a new city, that isn’t typically considered an “illness” — unless the symptoms are prolonged and harm an individual’s ability to perform normal daily tasks (such as working, sleeping or interacting with others). People suffering from depression often feel they lack the energy needed to get anything done. They may have difficulty concentrating on things or showing an interest in normal events. Many times, these feelings seem to be triggered by nothing; they can appear out of nowhere.
disorder: (in medicine) A condition where the body does not work appropriately, leading to what might be viewed as an illness. This term can sometimes be used interchangeably with disease.
electricity: A flow of charge, usually from the movement of negatively charged particles, called electrons.
electrode: A device that conducts electricity and is used to make contact with non-metal part of an electrical circuit, or that contacts something through which an…
Read the full article here