How are nerve impulses generated?
Neurones send messages electrochemically; this means that chemicals (ions) cause an electrical impulse. Neurones and muscle cells are electrically excitable cells, which means that they can transmit electrical nerve impulses. These impulses are due to events in the cell membrane, so to understand the nerve impulse we need to revise some properties of cell membranes. When a neurone is not sending a signal, it is at ‘rest’. The membrane is responsible for the different events that occur in a neurone. All animal cell membranes contain a protein pump called the sodium-potassium pump (Na+K+ATPase). This uses the energy from ATP splitting to simultaneously pump 3 sodium ions out of the cell and 2 potassium ions in.
