Every drawbridge has an operator who receives signals to raise or lower the bridge to allow passage of large ships from one side to the other. In the same sense, the sodium and potassium channels in an axon receive signals (action potential) to open and close their gates and allow passage of ions from one side of the membrane to the other
How would these steps relate to the a drawbridge raising and closing.
1. a graded potential brings the membrane to threshold potential.
2. Fast Na and slow K channels are activated.
3. Na rushes into cell, causing membrane depolarization
4. K channels fully open, and Na channel inactivation gates close.
5. K rushes out the cell, causing repolarization
6. K channels close slowly resulting in hyperpolarization Na channel gate reset