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Action potential: a small electrical event which is how information is passed from neuron to neuron.
Dermis: the inner layer of skin beneath the epidermis, composed of connective tissue, blood and sweat glands. It contains the nerves that process touch and pain information.
Epidermis: the outermost layer of cells that cover an organism.
Millimeter: a unit of length that is one thousandth the size of a meter, and one tenth size of a centimeter.
Nervous system: organ system made of a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals to and from different parts of the body... more
Receptor: a molecule on the surface of a cell that responds to specific molecules and receives chemical signals sent by other cells.
Stimulus: Any signal from the environment that causes the body to react.
The wind howls outside as the rain pounds against the window. With a sudden flash of lightning, the lights in your room go out. Vision won’t help very much in the darkness of the room, but you know there is a flashlight in the nightstand next to the bed. You move your hands toward it, find the drawer handle, and open it. You start to feel around for the flashlight.
As you touch each object in the drawer you can identify it immediately. After a few tries you feel the rubber grooves of the flashlight handle. With a sigh of relief you pull it out of the drawer and turn it on. While you may think you have psychic powers to be able to correctly identify the flashlight from the other items you touched, your skin did most of the work.
Skin has many types of receptors that help you feel the things that you touch. In your body, a receptor is a structure that can get information from the environment. The information is then changed into a signal that can be understood by the nervous system. Receptors that let the body sense touch are located in the top layers of the skin - the dermis and epidermis.
Receptors are small in size, but they collect very accurate information when touched. They may sense pain, temperature, pressure, friction, or stretch. Unique receptors respond to each kind of information. This helps provide the body with a full picture of what is touching the skin.
While each of these sensory receptors responds to a specific type of touch, they all act in the same way when they are activated. As part of the nervous system, these receptors will fire an action potential. Action potentials are signals sent by the special cells, called neurons, that make up the nervous system. They are used to share many different kinds of information within the nervous system. Action potentials from all of these receptors will send signals to both the spinal cord and the brain.
Neuroscientists still aren't sure how signals from these receptors are changed into information that a person can understand. For example, when you are tickled versus poked, you know right away what happened. But how does the brain let you know whether it's a tickle or a poke based on only a few action potentials? Scientists continue to study this question.
Image of hand touching water by Agustín Ruiz.
Patrick McGurrin. (2016, March 31). How Do We Sense Touch?. ASU - Ask A Biologist. Retrieved April 20, 2019 from https://askabiologist.asu.edu/explore/how-do-we-feel-touch
Patrick McGurrin. "How Do We Sense Touch?". ASU - Ask A Biologist. 31 March, 2016. https://askabiologist.asu.edu/explore/how-do-we-feel-touch
Patrick McGurrin. "How Do We Sense Touch?". ASU - Ask A Biologist. 31 Mar 2016. ASU - Ask A Biologist, Web. 20 Apr 2019. https://askabiologist.asu.edu/explore/how-do-we-feel-touch