PSL300H1 Lecture Notes - Lecture 8: Dermis, Axon Terminal, Myocyte
Document Summary
Somatosensory receptors: type: mechanoreceptor, cutaneous receptors: detect skin pressure and, proprioceptors: detect forces in muscles and stress joints. Pacinian corpuscle: a alpha largest cutaneous receptor so biggest axon and fastest conduction velocity, huge receptive field ex. 1-2mm across, gets larger when away from fingertips (ex. Fastest conducting sensory afferent in the body, biggest axon and conduction velocity: a lot of attention paid to by nervous system, made of specialized intrafusal" muscle fiber serving as a sensory organ. Fiber used, not cell- fiber = many cells fused together. In normal skeletal muscle cells, nuclei spread out evenly but in intrafusal fibers they are close together in central region so balloons out where central terminals located, most metabolically active area, responds to stretches )ex. Stretching bicep, activating spindles, cause act pot of group 1a and 2 axons) Joint receptors: detect orthogonal (paciniform, layer like onion skins, simpler version of pc and not as sensitive, ex.
