====== Thermoception ======

//Thermoception, //or the body's ability to sense heat (and cold), has been studied for several centuries. It's thought that the ability to detect temperature is extremely ancient in evolutionary terms. Going back as far as the evolution of[[https://en.wikipedia.org/wiki/Archaea|Archaea]].

In humans and other mammals, specialist nerve cells in the skin (and some other organs) called //thermoreceptors// can detect temperature changes of just a few degrees C. They typically have 'raw' nerve endings which aren't sheathed in myelin.

It has been found that there are (at least) two types of //thermoreceptors, //one detecting higher temperatures, and the other responsible for cold sensing.

It's not currently known exactly how the sensing works - in either type of cell.

>Thermoreceptors have been classically described as having 'free' non-specialized endings; the mechanism of activation in response to temperature changes is not completely understood."\\ \\ Source : [[https://en.wikipedia.org/wiki/Thermoreceptor#Structure|Wikipedia]]

It's thought that chemical changes in proteins at the ends of the fibres, brought about by contact by a hot or cold object or environment, are converted into an impulse response (or change in firing rate) of the nerve cells. The changes are detected very rapidly - in a few milliseconds. Exactly how this happens is unclear. Current research suggests that there are likely to be a wide range (a 'constellation') of thermally sensitive chemicals involved.

As yet, no research projects have clarified whether the nerve sensors for pleasurable sensations of warmth are the same ones which are responsible for pain caused by heat (see below).

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Also see : [[content:life_sciences:human_body:heat_pain]]