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Haptics: Cold

Haptics is the study of the sense of touch. There are many parts to touch, and five different types of touch nerve in the nervous system. The sense of touch covers our body like a sheath: Every square centimetre of skin has haptic nerves, of five different types. They let us feel and immerse in the world around us, in the way the other senses do not. Pressure, texture, heat, cold, pain. Five key aspects to life.

Here, we are looking at cold.

So what detects cold?

The central nervous system descends via the brainstem from the back of the brain, and moves out to cover the entire body. Major nerve tendrils run across the face, along the shoulders, down the arms and legs, and cover the midsection. They reach into the most intimate areas, and they head to the outer extremities, continually branching out into smaller and smaller divisions as they go. Some paths head into the body, deep into the organs themselves, sending commands what to do, and relaying data back to the brain.

At the very end of the branching, nerve fibres are down to single-cell widths. The axons are only large enough to transmit one signal stream, serially, each. At the far ends of these threads are sensory devices. Each one different, for a different purpose. One detects pressure, one detects damage, one detects heat, one detects texture. The last, Krause's end-bulb, sometimes referred to as krause's corpuscle, detects cold.


A Krausse End

Krause's end-bulbs are found across the skin, inside the mouth, and clustered at the tips of both gender's genetalia. They are thought to be thermoreceptors sensitive to cold and activated by temperatures less than 20 ?C, however at this time, nowhere near enough research has been done on cold nerves to be certain.

In fact, little work has been done since Dr Wilhelm Kraus, a German anatomist, first discovered them in thje final years of the nineteenth century.

What we do know is that they can detect low-frequency vibrations, and have a fairly similar structure to Meissner's corpuscles.

Unlike other nerve endings, bulb ends never lose their myelin sheath. Instead, the sheath expands over the growing bulb, like a snake swallowing a large egg. Inside the bulb, the myelin sheath spreads out into interconnected strands. Between them, the nerve fibre splits apart into a tree-like formation, branching to fill up space.

At the very core of the bulb, is a pool of fluid, into which each nerve ending plunges.

The precise workings of the bulb end, are still a mystery to us.

Further Reading

Grey's Anatomy Entry

Staff Comments

 


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