One of my favorite parts in particular was in Chapter 14, where it talks about how we experience pain. According to the slides, pain is a multimodal phenomenon containing a sensory component and an affective emotional component. There are three types of pain: nociceptive pain, which signals impending damage to the skin such as severe pressures and temperatures, inflammatory pain which is caused by damage to tissues and joints or by tumor cells, and finally neuropathic pain, which is caused by damage to the central nervous system. Pain can occur where there is no stimulation on the skin, and can be affected by a person's attention to it. How pain occurs is a very complex model, and I became very interested in people who do not feel pain. The book talks about how shifting your attention can decrease pain, and surgical patients who were told what to expect had a increased healing time and requested to leave the hospital earlier. There is a rare disease called Congenital insensitivity to pain with anhidrosis, or CIPA, which is genetic and results in a person being unable to feel any pain. These people are able to eat scalding hot food without feeling any burn, take hard falls on pavement and feel nothing, and are completely unable to sense extreme temperatures, whether cold or hot; which keeps their body from cooling down by sweating. However, they are able to feel hunger, textures of everyday items, and other normal things people use their senses for.
The reason for this is because the genetic mutation that causes CIPA only disrupts the small nerve fibers that carry sensations of pain, cold and heat to the brain.
This topic definitely related to real world issues. Though there are not many people in the world with this condition, it poses a major problem for the family and friends of someone diagnosed with CIPA. People who do not have CIPA may take for granted how lucky we are to have pain receptors. Sure, it definitely hurts when we burn our tongue or scrape our knees, or even something more serious such as breaking an arm; but imagine if you couldn't feel it at all? Pain is our body's way of telling us that something is wrong and needs to be fixed, and our entire body works together to keep it in perfect homeostasis as often as it can- something to be very grateful for.
The following is a video of a little girl who suffers from CIPA, and how dangerous it may be:
Another child with a similar pain-free disease called HSAN: