BCS 240 Lecture Notes - Lecture 24: Ventral Posterior Nucleus, Dorsal Root Ganglion, Periaqueductal Gray
1 Nov 2018
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Wednesday, october 31, 2018 divisions of the somatosensory system: exteroceptive system (external s(cid:415)muli) touch, pain, and temperature proprioceptive system body posi(cid:415)on in rela(cid:415)on to joints, muscles, and balance interoceptive system internal body condi(cid:415)ons. A fibers axons that are myelinated for rapidly adap(cid:415)ng receptors. Proprioceptive system: types of proprioceptors: muscle spindles embedded in/parallel with muscle bers that signal muscle length (extended vs. contracted) ongoing signal (slowly adapting) Golgi tendon organs in series with muscle bers that signal muscle tension (force generated by the muscle) signal builds over time (slowly adapting; ex: carrying a heavy object over time) Pacinian corpuscle rapidly adap(cid:415)ng proprioceptors in joints (respond to joint movement) Information streams: dorsal stream carries where informa(cid:415)on (ex: body placement/pain loca(cid:415)on) to parietal cortex (to direct attention to the source/inform intent to act) ventral stream carries what informa(cid:415)on (ex: object shape) to prefrontal cortex.
