1.   It allows sodium ions into the dendrite, which raises its voltage temporarily.

2.   Pancreatic juice for example contains a high concentration of sodium ions, and variable concentrations of chloride and bicarbonate ions.

3.   Should the supply of sodium ions presented to the distal exchange sites Decrease, potassium excretion Decreases also.

4.   That blast of sodium ions entering the neuron is the impulse starting.

5.   Typically, sodium ions are excluded and potassium ions are hoarded.

6.   As the impulse passes any point on the fibre, the membrane allows a sudden thrust of positive sodium ions.

7.   This in turn brings about an increase in the permeability of the sodium ions of the adjacent part in the direction in which the impulse is passing.