Unit 12 jt mechanoreceptors and antinociceptive systems

types 1 (ruffini) and 2 (pacini)

w/in jt capsule; stimulated w/ movement; myelinated ns (fast)

types 1 (ruffini) and 2 (pacini)

roles in proprioception and kinesthetic awareness (sensitive to change in length and deformation)

type 1 (ruffini)

slow adapting, low threshold, sensitive to tensile Fs

type 2 (pacini)

fast adapting, low threshold, sensitive to compressive Fs

type 3 (golgi)

w/in ligs, slow adapting, high threshold, active in extremes of jt motion (end ranges)

type 4 (free n endings)

high (critical) threshold, noxious stim, nociceptive input sent via unmyelinated ns (slow)

peripheral n desensitization

topic meds and creams (biofreeze) desensitize type 4 mechanoreceptors

dorsal horn inhibition

heat, massage, manipulation, TENS; blocks type 1 and 2 signals from reaching CNS

descending system

MT, opioids; blocks pain signals via higher lvls w/in NS

horm system

endogenous opioids

amygdala and corical lvl

expectations, excitement, placebo

amyglada

component of limbic system; mediates the emotional aspects of pain and cerebral cortex; modulates lvls of excitement and expectations