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I thought a lot about the end of our discussion on Thursday and the mention of pain.  I decided to do some research on the subject after it was suggested that pain is only experienced in the brain.  I found some interesting results that seem to reveal more about the already complex nervous system that has been laid before us this semester.   Upon the discovery of the nociceptor, a specialized sensory receptor that is only activated by painful stimuli, I realized that pain is much more complex a sensation than I had originally thought at the end of class.

One of many specialized sensory receptors, like photoreceptors or olfactory receptors, nociceptors relay information to the brain.  In this case, the information is relayed in order for the brain to seek cessation of the stimulus causing the activation of the nociceptors.

Although this sounds extremely simple and straight forward, I began to think about reflexes.  A reflex is an involuntary action.  This could be anything from the blinking of the eye when the sun is bright to rapidly removing a hand from a hot surface. To me, these actions are incredibly interesting because they are done without the use of the brain. Signals from the sensory neurons are sent only to the spinal cord, which relays information back to the motor neurons that signal an action to occur.  This pathway, known as the reflex arc, allows for minimal damage of the body by responding in the quickest possible manner.  I just thought this was worth mentioning given our discussion of paraplegia on Thursday.  I read some sources that mentioned thatthis same type of reflex arc is employed by paraplegic patients as well.