16 Somatosensory Receptors

Neurosci 2950 15756 15761 2009 ruffini receptors in

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Unformatted text preview: ngential J.Neurosci. 29(50): 15756-15761 (2009) (Ruffini receptors in skin & tendon) force in joint capsule (group II) Class of Proprioceptor Group I: Ia (muscle spindle) Ib (Golgi tendon organ) Group II: (Joint receptor afferents) (Some muscle spindles) Group III: (thermoceptive, nociceptive) Group IV: (thermoceptive, nociceptive) Info Large diameter, myelinated Up to 75 m/s in humans (fastest in body) Medium diameter, myelinated Like... A cells and smaller r.f. of afferent women generally have smaller fingertips than men; hence they perceive finer surface detail October 20 3 Proprioceptors A Muscle spindle: adequate stimulus is Small diameter, myelinated Ia afferents) A passive stretch (group Golgi tendon organ: adequate stimulus is Small diameter, unmyelinated C active force (group Ib afferents) joint receptors: detect orthogonal j p g (paciniform) or tangential (Ruffini receptors) force in joint capsule (group II) 2 of 5 PSL302Y: Lecture 15, by Prof. MacKay# Wed., Oct.20, 2010 Group Ia Proprioceptor: Muscle spindle - Largest diameter, fastest-conducting sensory axon - Slowly adapting - Passively activated by stretching the muscle/skin - Specialized intrafusal muscle fiber (inside spindle) serves as sensory organ - Central zone, containing nuclei (fusion of many cells = fusiform/bulge shape) - Wrapped by group Ia sensory axon Somatosensory Receptors - Stretch on muscle = stretch central zone = distort sensory terminal of afferent = depolarization...
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This note was uploaded on 03/27/2012 for the course PSL PSL300 taught by Professor Mackayfrench during the Fall '11 term at University of Toronto- Toronto.

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