Touch+and+Pain+P2+Hannah,+Lauren,+Sarah,+Ariella,+Ilana

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Did you know that athletes can withstand more pain than people who do not exercise? Coincidentally, people who smoke or are obese report more pain than others. Touch and pain are hard to define, but the International Association for the Study of Pain defines the sense of pain as an “unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage,” and touch is the response to pressure.  Touch and pain may be subjective, but the stimulus for this senses are identical for every person. The skin contains receptors called mechanoreceptors that “translate physical forces into nerve impulses” (wise geek). This information is then processed in the postcentral gyrus. About 90% of this area of the brain is devoted to processing touch signals from the hands and face. In order for the brain to process pain, the human body first must come in contact with stimuli, such as strong pressure, pinching, squeezing, twisting, or extreme temperatures. A nerve ending then senses the stimuli and sends the signal to the central nervous system. The brain then receives this information and further processes it. Nociceptor neurons are responsible for transmitting the sensation of pain. The nociceptors that are myelinated are active shortly after the body comes in contact with stimuli. This is because these nociceptors create a fast pathway for the sense of pain to travel to the brain. Slow pathways, made up of unmyelinated neurons, send information through the limbic system. This takes about 1-2 seconds longer, and is responsible for processing longer lasting pain, such as aches and burns. Have you ever wondered why your finger tips are more receptive then other parts of your body? Well this is due to the fact that touch receptors, or mechanoreceptors (which are located in human skin) are not distributed evenly over the body. For example, fingertips and tongue may have as many as 100 per cm2 whereas the back of the hand fewer than 10 per cm2. An absolute threshold is the lowest amount of physical energy received by the brain that allows humans to perceive the information. The absolute threshold for touch for humans is the wing of a bee on ones cheek. The cortex deals with pain perception. The size of the cortex directly correlates to the pain threshold of the species. For example, the cortex gets smaller going from humans, to primates, mammals, birds, reptiles, amphibia and lastly fish, which only have a rudimentary cortex. Touch and pain are a vital part of survival. Without these senses, life expectancy would greatly decrease. Touch is one of the most important senses, without it animals would not be able to recognize pain (such as scalding water), and they would not be able to respond to their environment. This would make it difficult for animals to survive. For example, if humans feel cold, they know to put on warmer clothing or to migrate somewhere warmer. Pain acts as a warning system. Touch and Pain are senses through which people and animals interpret the world around them.

__Sources:__ [|__http://www.bbc.co.uk/science/humanbody/body/factfiles/touch/touch.shtml__] __http://www.sciencedaily.com/releases/2011/09/110908124136.htm__ [|__http://www.ncbi.nlm.nih.gov/pubmed/10349356__] [|__http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/Mechanoreceptors.html__] [|__http://www.alleydog.com/101notes/s&p.html__] [|__http://science.howstuffworks.com/environmental/life/human-biology/pain.htm__] [|__http://www.webmd.com/pain-management/features/whats-your-pain-tolerance__] [|__http://www.faqs.org/health/topics/3/Touch.html__] [|__http://www.humanehealthcare.com/Article.asp?art_id=584__] [|__http://www.wisegeek.com/how-does-the-sense-of-touch-work.htm__] <span style="background-color: transparent; color: #000099; font-family: Arial; font-size: 15px; vertical-align: baseline;">[|__http://science.howstuffworks.com/environmental/life/human-biology/pain3.htm__]

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