Photo: Geoffrey Smith (Flickr)
Have you ever wondered how the pain from a stubbed toe makes it’s way from your foot to your brain so you can say “ouch?”
We might explain the feeling as an initial thud from hitting the table leg, then sharp pain, and then, a few seconds later, a throbbing pain flooded the toe.
Thud Vs Throb
Let’s first explain why you felt that delay between the thud and the throbbing pain.
We have three different kinds of nerve fibers that connect the touch and pain receptors in our skin with the brain, and sensory information travels at different speeds on each type of nerve fiber.
The fastest nerve fibers have a fatty insulation sheath that allows the signals to speed along at 100 feet per second. These speedy fibers connect the touch receptors to the brain. That’s why the very first message your brain received, and the first thing you felt, was thudding against the table leg.
All About Touch Receptors
The second-fastest nerve fibers carry messages not from the touch receptors, but the pain receptors; that explains the sharp pain a split second after the thud.
Last but not least, the slowest nerve fibers also carry messages from the pain receptors. They cause what’s called second pain, the throbbing pain you feel a few seconds after you stub your toe.