Pain

Modified: 2026-08-06 7:27 PM CDST

• The receptors for pain are free nerve endings in the skin.
  • Those free nerve endings cover most but not all of the skin.
  • So, it is possible to find parts of your skin that do not respond to pain.

• Billions of dollars are spent each year to treat pain as a symptom.
  • Much of that money is spent on drugs, hypnosis, and TENS (transcutaneous electrical nerve stimulation) units (they are attached to the affected area, and deliver mild shocks in response to the pain). In some cases, surgery is indicated, and nerves may be cut to relieve pain.
  • Behavioral management is also used.
  • People may be taught to ignore pain.
• The environment can affect pain.
  • During World War II surgeons found that soldiers required much less morphine than prewar civilian patients did.
  • They attributed that difference to the differences in perception of both groups.
  • To civilians, going to the hospital is an unwelcome experience and they expect pain.
  • However, to soldiers in battle, going to the hospital is a welcome experience.
  • Their feelings are of relief, not of dread.
  • So, pain can be affected by the environment, and that probably forms the basis for behavioral treatments for pain.
• The physiology of pain is has been described by gate theory.
  • In gate theory, two types of pain pathways are proposed.
  • One type conducts the pain impulse quickly, the other slowly.
  • They both come into a "gate."
  • Usually we cannot prevent the fast-acting pain from being detected.
  • However, gate theory says that if the gate is stimulated, say by rubbing, then the slow-acting pathway will be closed.
  • Take the following example.
  • You hit your thumb with a hammer by accident. s
  • Then you quickly rub your thumb.
  • By doing that you may close the slow-acting pathways, and not feel throbbing pain in your thumb later.
• Drugs that relieve pain are called analgesics
  • Aspirin and tylenol are analgesics.
  • So is morphine, a very powerful analgesic.
  • Unfortunately, morphine also has addictive properties.
  • Endorphins are analgesics manufactured by the body.
  • They are produced in response to pain and they may account for individual differences in pain perception.
  • One person may just produce more endorphins than another in response to the same painful stimulus, and thus report less pain.
• Anesthetics are drugs that deaden all of the senses.
• When you go to the dentist for a tooth extraction or cavity, you will get an anesthetic, novacaine.
• Novacaine causes you not to feel pain, touch, hot, or cold.
• So, when you attempt to rinse your mouth, you cannot keep your lips on the cup easily, or feel the cup.
• I was shocked when a surgeon once injected me with xylocaine, and then picked up his scalpel.
• I thought he would wait awhile, but he assured me he did not need to, and proceeded to remove a small abscess, without my feeling anything.

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