Ion channels
- Ions traverse the plasma membrane of cells through channels.

- These channels are in fact embedded transmembrane proteins.

- Sodium (Na) channels are voltage gated channels, which can be
opened or closed in response to changes in charge across the plasma membrane.

- These voltage gated sodium channels are crucial for the flow of action potentials in excitable membranes.

- The diagram on the right depicts a sodium channel, and the orange filled circles represent tetrodotoxin (TTX) binding sites.

  "voltage gated sodium channels"
   
Action Potentials
- Action potentials, involving the passage of Na+ ions and K+ ions
along nerve cell membranes, are electrical messages sent out by the
brain to various parts of the
body to instruct them on the appropriate
action to perform.

- The flow of the Na+ ions into the nerve cell is an essential step in the conduction of action potential in nerve fibers and along axons.

- The Na+ ions flow through the cellular membrane via the Na channels.

- As a result of the influx of Na+ ions, the cell membrane depolarizes and the nerve impulses continue traveling towards the target muscle cells.

  "Action potential"