Why cant we feel certain small objects when we touch them on one part if the body, but on a completely different part of the body we can?

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Say a hair, for example, touches your fingertip and you cant feel it. If you bring that same hair to say, your ankle, you can feel a slight tingling.

In: Biology

In your finger vs ankle scenario it’s really just because of how thick the skin is. You can’t feel it on your finger because the skin in thicker and usually more callused. Your ankle however is more thin skin since you don’t use them in the same way you do your hands so the nerves are closer to the surface of your skin

Certain parts of the body are adapted for more precise feeling. Fingertips are used to feel around, so the skin contains more numerous and sensitive nerve ending adapted to transmit this extra information back to the brain.

Other parts like the back or arms have thicker skin and less sensitive nerves, meaning they are less likely to trigger the fine reactions that you experience as “feeling” a tickling hair.

The fingertips are extremely sensitive to touch the fingerprints are folds in the skin to maximise the surface area and increase the sensitivity.

It depends on how many nerves there are put 3 fingers on somebody’s back and ask them how many things are on their back