““While the mechanisms involved in electrochemical signaling are complex, the basic principles are simple. Just as a battery maintains its charge by housing different electrolytes in different compartments, a cell has a charge owing to different amounts of various salts in and outside the cell. There is more sodium on the outside of cells and more potassium inside. (That's why salt balances are so important in our diets.) When a mechanoreceptor is activated, let's say by your thumb touching the spacebar on a keyboard, specific channels open up near the point of contact in the cell membrane that allow sodium to pass into the cell. This movement of sodium changes the electric charge, which leads to the opening of additional channels and increased sodium flux. This results in the depolarization that propagates along the length of the neuron like a wave propagating across the ocean.””
