How a nerve impulse passes along a non-myelinated neuron
Below: ion pump in a plasma membrane.
At rest there is a potential difference between the outside of the membrane of an axon and the inside. The usual value used is - 70mV.
Outside is positively charged.
Inside is negatively charged.
Concentration of Na+(Sodium) is higher on the outside.
Concentration of K+(Potassium) is higher on the inside.
Both are positive so there is no potential difference. The distribution of Cl- makes the resting potential. This is maintained by the properties of the selectively permeable membrane.
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.
Although the potential difference is back to original values, the sodium and potassium ions are in the wrong place.
The sodium/potassium pump will return them to original positions via active transport.
Action potentional is the time of depolarization (1msec).
That is all for Part one!
Drafted by Venetia (Biology)