2Touch Touch receptors are on the skin Skin is the largest & heaviest organ (20 sq. ft. & 6 lbs.)Four basic skin senses arePain, warmth, cold, and pressureAll skin sensations are a combination of these four basic senses
3PressureOnly pressure has identifiable neural receptors – Pacinian Corpusle – located beneath the skin, it converts pressure stimulation into neural messages it sends to the brain.Constant pressure causes sensory adaptation and it either reduces the number of signals or quits sending them all together. (like the clothes on your body)Itch is caused by "itch-sensitive" neurons that respond to histamines.Sensory receptors are located unevenly on the body so certain areas are more sensitive than others.
5What purpose does pain serve? Pain is your body’s way of telling you something is wrong. It tells you to change your behavior immediately.Any external stimulus that can produce tissue damage can cause pain.Internal stimuli like disease or infection can also cause pain.Certain areas of the body are more sensitive than others
6Gate-control Theory of Pain Pain messages travel on one set of nerve fibers containing pain gates.The gates are open when pain is felt.Other sensory messages go through another set of fibers.The nonpain fibers can close the pain gates to stop the sense of pain.
7The Process of Gate-Control Theory Intense stimulus activates small-diameter sensory fibers called free nerve endings.Free nerve endings carry their messages to the spinal cord, releasing a neurotransmitter called substance P that activates other neurons to send their messages through the open spinal gates to the thalamus.Thalamus sends pain signals to frontal lobes and limbic system.Brain interprets pain and sends messages to the spinal cord to either close or open gates. If more gates open, pain gets worse. If gates close, less pain experienced.Endorphins can be released which inhibit the release of substance P thus lessening pain.Muscle Tension, psychological arousal and rapid heart beat can all produce or intensify pain.
8The Pain Process 2. Free Nerve Endings Carries Message To… Activates (located in skin, muscles, & internal organs)Carries Message To…Activates3. Spinal Cord(which releases substance P)1. Intense StimuluscausesCloses the GatesPain is reduced4. Other Neurons to activate & send pain message to the Thalamus through open Spinal Gates. Brain then…Leaves Gates OpenPain is intensified
9Biopsychosocial Perspective Our experience of pain is much more than neural messages sent to the brain.
10Can we distract ourselves from the pain? YES! An athlete who is injured doesn’t realize it until after the game.Emotions and cultural differences can influence the brain's decisions on opening or closing gates.Person's mental state can influence one's experience of pain.Distraction – focus on a nonpainful stimulusImagery – create a vivid mental image can help control pain.Positive Self Talk – "It hurts, but I'm OK." Or redefine pain.Counter irritation – create a strong competing sensations that's mildly stimulating or irritating. Rubbing a sore area. Stimulating the “gate-closing” nerve fibers can help lessen pain. Rubbing a stubbed toe creates a competing stimulation that will block some of the pain messages. Putting ice on a bruise sends cold messages to the brain which lessen the pain messages.Relaxation – Deep breaths and relaxing deeply
11Virtual Reality Pain Control For burn victims undergoing painful skin repair, an illusory virtual reality can powerfully distract attention, thus reducing pain and the brain's response to painful stimulation
12Pain and Phantom PainThe brain comes prepared to anticipate that it will be getting information from the limbs of the body. This is why amputees may experience sensations in a phantom limb.Phantom limb sensations – the brain is misinterpreting central nervous system activity that occurs in absence of the normal sensory input from that limb. This can be true of the other senses as well.