What does myelin do?
Speeds up the action potential/the rate at which the signal is sent
What is the resting potential inside of an axon?
It is negative with respect to the surface, by about -70 millivolts
What is the excitation threshold?
about -55 millivolts, action potential then occurs
How does the action potential work?
The resting potential depends on the presence of positive sodium ions outside the cell membrane. Ion channels allow charged ions to enter and exit the cell. In the resting state, sodium ions are kept on the outside by a sodium pump, but in-going ion channels remain closed.
What happens when a pulse is applied?
Incoming channels open, allowing sodium ions to pour into the cell, thereby reversing the voltage difference. Sodium channels close, potassium ions go outside the cell, Sodium ions are then pushed outside the cell, and potassium ions are drawn inside. Inside and outside concentrations are returned to their original levels.
