The Sense of Touch
We have previously looked at four of the five basic senses: Taste, Smell, Hearing, Sight. Today we will take a brief look at the fifth sense: the sense of touch.
In the previous four senses, the organ(s) involved have been relatively small and confined to one location on the body. The sense of touch involves the largest organ, the skin, which covers the entire body. The skin has millions of receptors contained within its thin layers. These receptors are responsible for detecting any kind of external stimulus; touch, wind, temperature, vibration and pressure. Once the stimulus has been detected, they relay that information to the millions of nerve endings also located in the skin which in turn carries those impulses to the brain where they are interpreted and reacted upon.
There are six basic types of receptors in the skin that are involved in the sense of touch.
I. Meissner’s Corpuscles – Also known as tactile corpuscles, they are found everywhere in the skin with higher concentration in the hairless area of the skin such as the palms of the hands, soles of the feet, lips and nipples. Meissner’s corpuscles react very rapidly to light touch and vibrations as low as 50 Hz.
II. Merkel’s Disks – These receptors are found in all areas of the skin. They react slower than Meissner’s corpuscles. Merkel’s disks detect changes in pressure as well as the texture of whatever is touching the skin. They can detect lower vibrations in the range of 5-15 Hz.
III. Pacinian Corpuscles – These receptors are located in the layer of connective tissue in the hairless skin areas. They detect deep pressure and are extremely sensitive to slightest vibration, even it is several inches away.
IV. Ruffini’s Corpuscles – Also known as Ruffini’s end organs or bulbous corpuscles. These receptors are spindle shaped and go deep into the skin. They are found in the hairless areas of skin and respond rapidly to any stimulation. They detect the sense of touch and pressure. They detect movement along the skin aiding in the ability to grasp and hold objects in the hands, toes and lips.
V. Hair Follicle Receptors – These are receptors located in each hair follicle. They detect any movement of the hair, even if the skin is not touched.
VI. Free Nerve Endings – There are several types of free nerve endings:
A. Mechanoreceptors – They detect touch and pressure.
B. Thermoreceptors – They detect changes in external temperature which are not harmful to the body.
C. Nociceptors – They detect pain and send the signals to the spinal cord and brain. Nociceptors far outnumber all other types of receptors in the skin.
1. Thermal Nociceptors – They detect changes in temperature that can be harmful to the body.
2. Silent Nociceptors – They only become activated once the skin around them becomes inflamed.
3. Mechanical Nociceptors – They detect extreme pressure and deep scratches into the skin.
Whether you realize it or not, the sense of touch is very important in your ability to detect the world around you. Every time you reach for anything with your hands, you are relying on the sense of touch to hold it or pick it up. The sense of touch is what allows me to type this article on the computer.
Can you imagine what it would be like without the sense of touch? You would not be able to hold anything in your hands, nor would you be able to feel the floor beneath your feet. You could lean against a hot burner on the stove and not feel your skin being burned. Worse yet, you would not be able to feel the soft tug of your child’s hand trying to get your attention.
People without vision learn to function by using their sense of hearing, smell and touch. People without hearing rely heavily on their sense of vision and touch. People without taste or smell miss out on the pleasures of different foods and odors. But people without the sense of touch are almost lost in the physical world around them. Though they try to rely on the other senses to help them cope in the world, it is very difficult to be able to move around and function without the sense of touch.
The sense of touch is also an important part of how we communicate with each other. Jesus often taught and healed by touching. He touched the leper and healed him in Matthew 8. He touched and healed Peter’s mother-in-law also in Matthew 8. He healed the blind men in Matthew 9 by touching their eyes. And in Matthew 19, Jesus told his disciples to let the children come to him and he received them and touched them and healed them.
The senses of touch, vision, hearing, smell and taste are truly wondrous testimonies to our Creator God. He knew exactly what we needed in order to survive and live in the world that He created for us.
A delightful nature story in ‘Dr Seuss-style’ rhyme about an oxpecker bird who removes ticks and other nasties from the skin of a giraffe, for the benefit of both.With captivating artwork, it uses these two zany characters to teach about God’s design, and about relationships, in a way that young children can easily understand and enjoy. (Primary/Elementary) 32 pages