Section2-6 - 2/23/12 The Stimulus Spinal Cord Nociceptors:...

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2/23/12 1 Nociceptors: free nerve endings Activated by various chemicals Send info to spinal cord (spinothalamic) The Stimulus Many analgesics work by blocking the formation of these chemicals Nociceptor To spinothalamic system Spinal Cord Projection neuron: goes to brain Referred pain : pain felt away from injured area Visceral (internal) pain is difFcult to localize Internal organ and skin go to same projection neuron ( converge ) To lemniscal system Nociceptor To spinothalamic system Slow, Small ±ast, Large ±ree nerve endings, respond to chemicals Mechanoreceptors respond to touch, pressure Why does rubbing relieve the pain? Spinal Gate Control Theory Inhibitory interneuron To lemniscal system To spinothalamic system Large ( L ) Fbers close the gate (activate inhibitory interneuron) Shuts off the pain before it reaches the brain! L S Nociceptor Spinal Gate Control Theory Inhibitory interneuron To lemniscal system To spinothalamic system Input from L Fbers gets to spinal cord Frst Problem: Need to respond to pain quickly. This way, you shut it off when mechanical injury L S Nociceptor
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2/23/12 2 Inhibitory interneuron To lemniscal system To spinothalamic system Solution: some mechanoreceptors Activate the projection neuron
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This note was uploaded on 04/09/2012 for the course EXP 3202 taught by Professor Staff during the Spring '12 term at Florida State College.

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Section2-6 - 2/23/12 The Stimulus Spinal Cord Nociceptors:...

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