Charge is a property of matter that is described as either positive or negative. Positive charge comes from protons. Negative charge comes from electrons. Like charges repel, and opposite charges attract.

Electricity has to do with the movement of electrons through a conducting material, which is caused by a difference in charge across an area. In biological systems, the difference in charge is often due to variance in the concentration of ions on opposite sides of a membrane. This creates an electrical potential, or voltage, which is measured in volts. Therefore, the conductivity of a particular type of tissue in the body depends on what ions are present in the tissue and the mobility of those ions (Metherall). The cell membrane that separates ions outside the cell from ions inside the cell can act similarly to a capacitor (Harris).

voltage- difference in potential energy between two points; also "electric potential"; measured in volts (V)

current- flow of electric charge; measured in amperes (A)

conductor- material containing electrons that are free to move

capacitor- stores electrical charge, usually by separating positive and negative charge on either side of a gap

© 2005 Ana Marx