KAAP309 Lecture 13: Chp 13 notes
29 Nov 2016
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Sensory receptors: convert physical stimulus nerve impulses (specialized, respond to change in environ) Sensation (awareness) and perception (interpretation of stimulus) occur in brain. Receptive field: physical region over which each receptor can detect stimuli. Processing @ circuit level (ascending pathways: 1st order: (cell body or peripheral ganglion) receptor to 2nd order, 2nd order: transmit impulses to thalamus or cerebellum, 3rd order: thalamus to somatosensory cortex. Adaptation change in response in presence of constant stimulus. Tonic adapt slowly or not at all (nociceptors, proprioceptors) Peripheral nerves = afferent & efferent fibers, small blood vessels, connective tissue wrapper, subdivided into fascicles (each with many axons) Structure (in to out) = endoneurium, perineurium, epineurium) Spinal nerves: 31 pairs named according to origin along spinal cord. Dermatomes: skin region with sensory innervation from one spinal nerve; overlap some (all but c1) Destruction of single spinal nerve will not cause complete numbness.
