cell

In cellular membranes, the electric potential changes from the outside of the cell compared to the inside of the cell, this can be seen by neurons. This is called membrane potential and it selects for certain ions to move into and out of the cell. In order for ions to move into a cell, a channel must be opened. When this channel is opened it creates a change in the electric field which signals to other channels within the membrane to open eventually leading to a response from the cell.