Select from the dropdown lists to complete the text.
The membrane is ( highly, not highly ) permeable to potassium ions at this stage so too ( many, few ) move out of the cell. This makes the potassium gated channels close and the potassium diffuse back ( into, out of ) the axon in order to restore the resting potential. If there has been a build up of sodium inside the cell due to many successive action potentials then the ( sodium-potassium pumps, magical forces ) start working once more.