Nerves send electrical impulses by briefly letting sodium in and potassium out across their membranes — about 1 to 100 meters per second.
How it works, step by step
At rest, potassium is high inside and sodium high outside.
A stimulus opens sodium channels; sodium rushes in.
The inside flips positive — the signal moves down the axon.
Potassium flows out to reset; pumps restore the balance.
Myelin
A fatty sheath around many axons lets signals jump between gaps and travel much faster. Vitamin B12 helps maintain it.
Symptoms
This atlas explains how nerves work. It can't explain your symptoms. Sudden, severe or unusual headaches, or numbness on one side, need prompt medical attention.
Evidence & sources
Action potentials are generated by sodium influx and potassium efflux through voltage-gated channels. Evidence: established. Known: Described by Hodgkin and Huxley (Nobel Prize 1963) and confirmed extensively. Unknown: — Source: Hodgkin & Huxley, Journal of Physiology, A quantitative description of membrane current and its application to conduction and excitation in nerve (1952).