How can your fingertips tell smooth glass from bumpy sandpaper? Tiny touch helpers called Merkel cells are part of the answer.
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Merkel cells live in the bottom layer of your skin's outer layer, sitting among the skin cells there.
Each one is small and roundish. Right underneath it is the flat tip of a nerve, like a little cup. Together they make a tiny touch sensor.
Merkel cells are packed into the places you use most for feeling, like your fingertips and lips.
When something presses gently on your skin, the Merkel cell and its nerve notice. The nerve sends a message to your brain.
This helps you feel edges, shapes, and textures. It helps you button a shirt, pick up a coin, or read raised dots by touch.
Close your eyes and gently touch a coin, a leaf, and a sock with your fingertip. Then try with your elbow. Which can tell them apart better? You can also press Touch! on the 3D model.