HMB200H1 Chapter Notes - Chapter 12: Endorphins, Opioid Receptor, Trpv1
Document Summary
Mechanoreceptors: pacinian corpuscle deep in derms. Ruffini in hair and glabrous skin. Merkel"s disks nerve terminal and flattened, non-neural epithelial cell: epithelial is mechanically-sensitive part. Krause end bulbs border regions of dry skin and mucous membrane. Pacinian sensitive at 200-300hz (loud music) Meissner at 50 hz (rough texture: fluttering at lower frequencies. Pacinian onion-like layers make corpuscle insensitive to low-frequency stimuli: indent ap reformation removal ap. Pacinian layered capsule sensitive to vibrating, high0firequency, not steady pressure. Two point discrimination: fingertips highest resolution. 3) more brain tissue per square mm of fingertip. 4) neural mechanisms for high resolution discriminations. Primary afferent axons enter spinal cord through dorsal roots (cell bodies in dorsal root ganglion: aalpha group 1 13 -20 um 50-120 m/s. Proprioceptors of skeletal muscle: abeta ii 5-12 um 35-75 m/s. Mechanoreceptors: agamma iii 1-5um 2-50 m/s. Pain, temperature: c iv 0. 2 1. 5 um 0. 5-2m/s. Simpal cord: cervical cord (8, thoracic cord (12, lumbar (5, sacral (5)