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Preksha Dhyana
of the brain. Olfactory receptors adapt very rapidly and if the same odour persists, one ceases to notice it.
4. SENSE OF TOUCH ETC. The sense of touch is the most basic means by which a person makes contact with the world around him.
The ability to feel shapes and textures provides the brain with more precise information than the senses of sight and hearing. By holding an object (with closed eyes) the fingers can tell its size, general contours as well as whether it is rough or smooth, hard or soft, wet or dry. Unlike the other four senses, touch responds to more than one type of energy stimulus, temperature and pressure. Moreover, the sense-organs for touch are distributed all over the body. Thus the sense of touch is more than a single sense.
Sense of touch, pressure, heat, cold and pain are provided by a variety of specialized sense-receptors, which are not uniformly distributed over the surface of the body. While pain receptors are the most numerous, heat-receptors are the most sparse. While touch receptors are in the skin or in the tissues immediately beneath the skin pressure results from the deformation of deeper tissues. While some types of tactile receptors adapt slowly, others adapt within a fraction of a second. But for the rapid adaptation of many touch receptors, we would be unable to wear clothes.
Touch signals pass through the relay station of the thalamus and reach the appropriate area of the cerebral cortex in the parietal lobe.
Besides providing information about the temperature, texture and weight of an object, the sense of touch performs other important functions in our life. Shaking hands, hand holding, caressing and kissing are some examples of tremendous emotional impact. Pain
Sensation of pain can be extremely useful. It is the body's warning signal for urgent corrective action to prevent danger to the tissues. Pain receptors are stimula
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