How fast does a nerve signal actually travel?
Touch a hot pan and your hand pulls back before you even feel the burn - your nerves are fast, but not instant.
The fastest nerves in your body carry signals at up to about 120 meters per second, roughly 430 km/h. They hit that speed because a fatty wrapping called myelin lets the signal leap from gap to gap instead of crawling the whole way. Bare, unwrapped nerves that carry dull pain and warmth move far slower, closer to 1 meter per second.
Stub your toe and you feel the bump first, then a second later the real ache lands - the fast touch nerve beat the slow pain nerve to your brain.
Nerve signals are quick but have a real speed limit, and different sensations arrive at different times.
It explains why your reflexes can yank your hand back before the pain even registers - the body is buying you time.
Myelin = insulation that lets the signal skip gaps, like a stone skipping across water instead of swimming.
Learn the idea and practice English at the same time.