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29 Cards in this Set
- Front
- Back
What is pain
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Noxious sensation that if allowed to continue will cause tissue damage
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What detects pain
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Nociceptors
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What type of pain is there
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Physiological, inflammatory, and neuropathic
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What are the three things about the pain
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1 we can have pain and + nociceptors, 2 we can have nociceptor and no pain, and 3 we can have pain and no nociceptor
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Is pain edited, if yes by whom and what does the stimulus have to be register pain
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Yes pain is edited by our CNS and we feel pain only if the stimulus is intense enough, there is prior stimulation of pain and if there is inflammation
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What 2 phenomenon do we see with inflammation
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Hyperalgesia and allodynia
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What is allodynia
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Otherwise normal sensation like touching the hair will cause pain in inflammation
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What is hyperalgesia
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This when the magnitude of pain is increased and same stimulus will cause more pain
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What type of nociceptors do we have
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3 mechano nociceptors, thermo and polymodal
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What detects temperature of above 45 C
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Thermal nociceptors
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What detects temperature of below 45 C
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Regular thermo receptors
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What detects severe mechanical stimuli by sharp objects like stab
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Mechano receptors
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What is the most abundant nociceptor that detects dull pain and via what fibers
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Poly modal, it detects all stimuli and it detects it via C fibers,
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What kind of ending s do nociceptors have
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Free
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What kind of NT are released at these free endings
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Peptide NT called substance P and CGRP,
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What is the role of substance P
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It will sensitize the nociceptor neuron and cause vasodilation and allow the mast cells to get in and release more stuff
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What are the other things that are released at the free endings
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P2X, TRV1, TRV2, TrK A (NGF), prostaglandin receptor and bradykinin, all of these contribute to the pain response
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If you were making a drug, what would be the area of interest
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You’d be interested in free nerve endings
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What does TRPV1 detect and through what kind of fibers
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It detects moderate sensitivity to temp at 45 and it is sensitive capsaicin, expressed by both Ad and C fibers
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What does TRPV2 does, what fibers
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It does strong temp, above 52 and it is expressed by Ad fibers only
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Asides form nociceptors picking up the painm how else can pain be felt
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The CNS can be sensitized, basically in the presence of chronic stimuli and inflammation the brain can start to pick up substances like P2X, TRPV1 and then when these receptors bind their products, the dorsal root neurons also pick up these fibers and pain can be felt even if some one touches your hair
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What is referred pain
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Basically its deep pain from visceral nociceptors and felt by the cutaneous tissue elsewhere, for example during infarct, the pain is felt in the shoulder, because the fibers from heart and the arm project onto the dorsal root , the higher center can’t differentiate between them and pain is felt on both sides
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What is the placebo effect and on what phenom is based on
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Placebo effect is that if people are led to believe that something is going to make their pain better and then giving them substance even though it has no effect, will make them better. It is based on the fact that the soldiers in the battle don’t report as high pain but same stimulus in non- war will cause lot of pain, so the context in which we are will effect pain
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How can placebo effect be blocked
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By giving naloxone, (x) opiate receptors
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What is involved in self modulation of pain
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Spinomesencephalic tract acting through the periaqueductal gray
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What is descending control of pain
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This self modulation of pain, peri aquedctal gray send fibers down that project onto interneuron that release Enkaphlin, when enkaphlin is escited it will release inhibitory molecule to inhibit the spinothalamic pathway and Ad
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What does Rpahe nucleus release and what’s the function of this release
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5HT, serotonin, + enkaphlin, w/c inhibit the release of NT by C fibers and lower the activity that will be projected by the dorsal projection neuron
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What is the gate theory of pain
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Basically if during pain, we stimulate mecahno receptors like Ab we can take some of the pain away, this like when you fall and rub your knee
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What is the role of amygdyla
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It is a nucleus with in out limbic system that has to do with emotion and fear, it + periaqudctal gray to release opiates
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