Information travels down a neuron as an action potential. AP is generated by a stimulus of a receptor or from an AP from another connecting neuron.
4. this reduction of the potential difference is called depolarization.
5. As soon as the potential difference is above zero, sodium is only driven in by diffusion.
8. The potassium moves through the channels out of the axon.
9. The force behind this are diffusion and electrical forces.
10. This means the potential difference across the membrane will start to decrease - repolarization.
11. As soon as the mV valls below zero, potassium is only driven by diffusion.
12. The potassium pores will shut when the potential difference is restored to around -70mV.
Action potentional is the time of depolarization (1msec).
Repolarization is the refractory period and is divided into the absolute refractory state (1msec) followed by the relative refractory state (up to 10msec)
- During the absolute refractory state, no new impuse is possible.
- During the relative refractory state, the potential is below the original resting potential of -70mV and a stronger stimulus is required to generate an action potential.
RP: Resting Potential
AP: Action Potential
RFP: Refractory Period
An action potential is not generated by every impulse. A threshold potential needs to be reached, or the impuse fades out - it is called an "all or nothing response".
Drafted by Venetia (biology)