Tadashi brought Hiro at the nerve lab to meet his friends Gogo, Wasabi, Honey Lemon and Fred. Hiro is also a nerd and was amazed at the inventions that they made. When it was Tadashi’s turn to demontrate his work he inflicted a mechanical pain at Hiro with a duct tape. As soon as the nociceptors (pain receptors) recognize the noxious stimuli (scratch of the duct tape) located at the skin, it immediately creates an electrical stimuli by changing the negative ions to positive (depolarization). The first order neuron conducts the message by passing through the delta a fibers ( its myelinated so nerve impulse can travel fast) and goes at the posterior portion of the spinal cord which is the dorsal horn. First order neurons transmits the message at the synapses with the release of the glutamate to the second order neuron. Second order neuron goes up (ascending pathway) and passess through the spinothalamic tract. The thalamus in the brain perceives or recognizes the nerve impulse “Hiro, you have a nerve impulse and you have to feel pain.” Meanwhile the somatosensory cortex (it locates the pain) in the brain says, “Hiro, watch out the nerve impulse is in the forearm of your skin. Pain!” Then finally the limbic (emotion) tells Hiro, “Never ever get your forearm scratch again with a duct tape!” The lower or midportion of the brain can produce a natural (endogenous) way of stopping the pain. The periaqueductal gray matter stimulates endorphin to prevent pain from recurring.
Copyright to: Disney
The pain pathway describe above was an example of acute pain.
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