Neuro Study Guide

Neuro Study Guide - Sensory system = receptors that detect...

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Sensory system = receptors that detect stimuli in int/ext env, pathways that conduct info to brain and areas of brain that do sensory info processing Sensation = sensory info that reaches consciousness Adequate stimulus = the type of stimulus a receptor normally responds to 2 basic sensory receptor arrangements o Specialized nerve endings on primary afferents (potential propagated toward trigger zone) o Specialized receptor cells assoc w/ primary afferents (causes release of nt) Receptor potential is graded potential , so may be depolarizing or hyperpolarizing Primary afferent firing freq reflects magnitude of receptor potential which OFTEN reflects stimulus magnitude!! Factors that affect receptor potential magnitude o Stimulus strength o Summation o Receptor adaptation Slow – adapts w/o stimulus being changed Rapid – adapts when stimulus changed Receptive field = part of body where stim leads to activity in particular primary afferent First order neurons classified by axon diameter and conduction velocity Auditory cortex is in sup temp lobe Nonspecific pathways impt for setting level of alertness or arousal Stimulus intensity may also be indicated by # of primary afferents activated by stimulus (recruitment ) Acuity o More convergence means LESS acuity o Higher receptor density = MORE acuity o Small receptive fields = MORE acuity Hair follicles, Meissner’s and Pacinian corpuscles are receptors for touch, movement, and vibration ( rapidly adapting – respond to start/stop, change in stimulus) Merkel’s corpuscles and Ruffini’s endings are receptors for pressure ( slowly adapting – give stimulus duration) Primary afferent for temp are slowly adapting Transient receptor potential proteins Receptor potential produced by Na entry Other molecules that activate nociceptors: o Ions (K), serotonin o Inflammatory Histamine, bradykinin, prostaglandins 4 signs of inflammation: Redness, Heat, Tenderness, Swelling (Red Hots Taste Sweet) Acute physiological nociceptive pain = when noxious stimulus applied to normal tissue Neuropathic pain b/c of nerve damage or neuron damage o Causes: axotomy, shingles, diabetes o Central Pain = damage to pain-processing neurons in thal
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Referred pain happens b/c central neurons in pain pathway may receive input from BOTH somatic and visceral primary afferents and gets confused Central sensitization when body “learns” to be in pain and responds more strongly to it o Can reduce/prevent w/ ketamine but preferred w/ receptor blockers and NSAIDS NSAIDS (aspirin, ibuprofen) inhibit cyclooxygenase, ultimately preventing release of prostaglandins (inflammatory) via arachidonic acid A cetominophen seems to act on CB1 cannabinoid receptors or via serotonin 3 classes of motor movements o Reflexes o Voluntary o Rhythmic Motor Patterns (vol start/stop, “automatic” in b/w)
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This note was uploaded on 04/05/2012 for the course PHYS 601 taught by Professor Jenlucas during the Fall '11 term at Ohio State.

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Neuro Study Guide - Sensory system = receptors that detect...

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