Why do our nerves feel different sensations?



This may sound weird but I honestly don’t know. How are there different “pain levels”? How do we feel pain in our bones (are there nerves in bones? I really don’t mean to sound dumb!). How do we differentiate between hot, cold, a regular touch, or a prick and so on.

In: Biology

We have different types of sensors for different sensations; they’re all connected to nerves to relay signals back to our brain but the thing on the end is different for different sense.

Touch sensors measure pressure.

Temperature sensors measure heat flow (in or out).

Pain sensors measure “damage”, basically. You do have nerves coating your bones, and some (but not all) other interior stuff.

Taste & smell sensors react to particular chemicals.

We also have a lot of ability to aggregate signals…lots of touch sensors working together gives us texture, lots of taste & smell sensors together give us particular overall tastes, etc.

You can differentiate between different sensations, because the nerve endings have different types of receptors connected to them. Some receptors are sensitive to pressure, some receptors to cold temperature or hot temperature. And if the the tissue is damaged, the nerve endings will inform you about pain.

The different levels of pain are also an interesting topic. Of course, the bigger the damage, the more nerve endings are stimulated and the stronger pain you feel. But if you wonder, why inflamed areas of your skin are more painful (sometimes to the level that a slight touch will hurt), it’s because the immune cells responsible for the inflammation release chemicals that make the nerve endings much more sensitive to all stimuli.

Regarding the question about bones – the bones themselves actually don’t contain any nerve endings (though I’m only 99% sure about that), but the bones are actually enveloped in a layer of tissue called “periostium”, which does contain a lot of nerve endings. Also, I believe that the bone marrow might contain nerve endings, but, again, only about 90% sure about that.

And one more interesting fact to anyone wanting to know more about their senses – the reason why some foods cause the hot feeling (like chilli) or the cold feeling (like peppermint) is that they contain chemicals that have the ability to stimulate the specific receptors that are responsible for sensing hot/cold temperature.