Transmission of Action Potential
- The opening of sodium ion channels at one particular point of the neurone upsets the balance of sodium and pottasium ions created by the sodium/pottasium ion pumps. This creates local currents in the cytoplasm of the neurone. These local currents cause sodium ion channels further along the membrane to open.
- When an action potential occurs the sodium ion channels open at a particular point along the neurone.
- This allows sodium ions to diffuse across the membrane from the region of higher concentration outside the neurone into the neurone.
- the movement of sodium ions into the neurone upsets the balance of ionic concentrations created by the sodium/pottasium ion pumps.
- The concentration of sodium ions inside the neurone rises at the point where the sodium ion channels are open.
- This causes the sodium ions tp diffuse sideways, away from this region of increased concentration.
- The movement of charged particles is a current called a local current.
Voltage-gated Sodium Ion Channels
- Further along the membrane are more gated sodium ion channels.