Skin


Skin


Sense Organs :

     Receptors of any sense are same and receptors of different kinds of sensations are different to each other and there is a difference in its creation.The region of this sense of touch is expanded very large whereas other sense organs of the body are localized and work in a definite limited area. Besides touch, a person gets information about temperature, cold, pressure, pain, hurt, light, heavy, dry, smooth and other sensations by this sense organ. In the skin of whole body, there is a net of nerve ending of nerve fibers which gather different kinds of sensation and transmit into the brain. These are called receptors.  

     Receptors of any sense are same and receptors of different kinds of sensations are different to each other and there is a difference in its creation. Different kinds of receptors present in the skin are situated on a sufficient distance from each other. The location of special kind of receptor is known by applying adequate stimulus on the skin. That point is called the spot of that special sense. When the sense of touching points is known by touching hard hair on the points of skin, such points are called tactile spots. In this way, the spots on which a person feels temperature, cold or pain are called warm spots, cold spots and pain spots. Spots of any special sense are somewhere much and less on the other portion.     

     If any hard thing as point of pencil is touched by giving pressure on the skin, it is the sense of pressure and its receptors are of special class. Such kinds of receptors are founds on other portions of the body beside the skin. Such receptors are found in periosteum, under the tendons and in the mesentery glands too. Through this sense, we become aware about our body or the conditions and movement of its different portions. Such kinds of receptors are called Lamellated or Pacinian corpcels. A person knows about the condition and movement of the body through these receptors. For example, if you keep the one hand of a person whose both eyes are closed on the table and  say to him to keep the hand on the table on the same position, the person will keep his hand in the same position near the first hand easily.

     Similarly, receptors are different for different kinds of senses as tactile corpuscles for the sensation of touch, Pacinian corpuscles, Corpuscles of Ruffini, Corpuscles of Krause for pressure, nerve end organs of Golgi-Mazzoni organs Ruffini for temperature, nerve end organs of Bulbous corpuscles of Krause for cold, etc are end organs made by some special combinative tissues in which cutaneous nerve endings terminate. Muscle spindle, golgi body and end plates are the means of sensations of skin. Besides these, nerve endings of which transmit the feelings of pain and hurt forward are free viz these nerve endings are spread on the skin freely. Some nerve endings related to touch sense remain folded in the roots of hair of which the information of touch is got.  

     In this way, different kinds of receptors get different kinds of sensations. One kind of receptors can collect only one sensation; the nerve ending for temperature can be used for the sensation of touch.