揚州大学Chapter 9. Sensory PhysiologyAll figures are from internet, textbooks and papers, all rights reserved to the original authors
Chapter 9. Sensory Physiology All figures are from internet, textbooks and papers, all rights reserved to the original authors
OutlineSensory functions of Nervous System- General PrinciplesSpecific Sensorysystem- VisionCentralsulcusSomatosensory- HearingFrontal lobecortexassociationParietal lobeareaassociation-Vestibular SystemAuditoryareacortexTastecortex-SomaticSensationVisualcortex-ChemicalSensesOccipitallobeassociationareaTemporal lobeassociationarea
Outline • Sensory functions of Nervous System - General Principles • Specific Sensory system - Vision - Hearing - Vestibular System - Somatic Sensation - Chemical Senses
OutlineSection A. Sensory functions of Nervous System-GeneralPrinciplesSpecificSensorysystem-VisionCentralsulcusSomatosensory-HearingFrontal lobecortexassociationParietal lobeareaassociation-VestibularSystemAuditoryareacortexTastecortex-SomaticSensationVisualcortex-ChemicalSensesOccipital lobeassociationareaTemporal lobeassociationarea
Outline • Section A. Sensory functions of Nervous System - General Principles • Specific Sensory system - Vision - Hearing - Vestibular System - Somatic Sensation - Chemical Senses
General PrinciplesSensationsystema part of the nervous system-sensoryreceptorcells:receivestimuliform theexternal/internalenvironment-theneuralpathways:conductinformation(receptorbrain/spinalcord)-partsofthebrain:primarilyprocesstheinformationCopyrightTheMcGraw-HillCompanies, Inc.Permissionroauirodforreproduction ordisplay(a)ToCNSStimulusAfferentReceptorenergymembraneneuron(b)ToCNSVesicle containingReceptorcellchemicalmessenger
General Principles • Sensation system a part of the nervous system - sensory receptor cells: receive stimuli form the external/internal environment - the neural pathways: conduct information (receptor → brain/spinal cord) - parts of the brain: primarily process the information
Sensory ReceptorsSpecializedcellsorgroupofnerveendingswhichrespondtostimuliPerception of theworldare created bythe brain (CNS)frominfoderivedfrom the sensory receptors (neurons) of the PNS.Receptors transduce (change) different forms of sensation to nerveimpulses.Functional categories of sensory receptors-Photoreceptors light-ChemoreceptorschemicalsAirborne→smell;dissolved→taste,internal→pain-Thermoreceptors temperature-Mechanoreceptors touchandpressure-Nociceptorspain- Proprioceptors body position
Sensory Receptors • Specialized cells or group of nerve endings which respond to stimuli Perception of the world are created by the brain (CNS) from info derived from the sensory receptors (neurons) of the PNS. Receptors transduce (change) different forms of sensation to nerve impulses. • Functional categories of sensory receptors - Photoreceptors light - Chemoreceptors chemicals Airborne → smell; dissolved → taste; internal →pain - Thermoreceptors temperature - Mechanoreceptors touch and pressure - Nociceptors pain - Proprioceptors body position
Sensory ReceptorsCopyrighteTheMcGraw-Hill Companies,Inc.Permission requiredforreproduction ordisplaySkinsurfaceDermisEpidermisA-Tactile(Meissner's)corpuscle(lighttouch)B-Tactile(Merkle's)corpuscles(touch)C-Free nerve ending (pain)D-Lamellated(Pacinian)corpuscle(vibrationanddeeppressure)E-Ruffinicorpuscle(warmth)
Sensory Receptors
Sense OrgansAspecializedorganorstructurewherereceptorcellsareconcentrated and supported by affiliated cellsTypes- Eye vision-Ear hearingequilibrium-Innerear e- Nose smellontralsulcus- Tongue tasteSomatosensoryFrontal lobecortexassoclationParietal lobeareaassociationAuditoryareacortexTastecortexVisualcortexOccipitallobeassociationareaTemporallobeassociationarea
Sense Organs • A specialized organ or structure where receptor cells are concentrated and supported by affiliated cells. • Types - Eye vision - Ear hearing - Inner ear equilibrium - Nose smell - Tongue taste
General Properties of Sensory ReceptorsAdequatestimulusAparticular formof energyto whichareceptor ismostsensitiveMechanoreceptor,chemoreceptor,electromagneticreceptor(photoreceptor),thermolreceptor,voltagereceptorandetcSensorytransductionReceptor can converse the energy of stimulus into the electric energy ofactionpotential-anintermediatestepb/wstimulusandnerveimpulses-stationarydepolarizationofareceptor-graded accordingto stimulus intensity-receptorpotentialandgeneratorpotential(slow,transitional)
General Properties of Sensory Receptors • Adequate stimulus A particular form of energy to which a receptor is most sensitive Mechanoreceptor, chemoreceptor, electromagneticreceptor (photoreceptor), thermolreceptor, voltage receptor and etc. • Sensory transduction Receptor can converse the energy of stimulus into the electric energy of action potential - an intermediate step b/w stimulus and nerve impulses - stationary depolarization of a receptor - graded according to stimulus intensity - receptor potential and generator potential (slow, transitional)
General Properties of Sensory ReceptorsCopyrightTheMcGraw-HillCompanies,Inc.Permissionrequiredforreproduction ordisplayStimulusStimulus intensityReceptormembraneMyelinReceptorpotentials(mV)FirstnodeofRanvierThresholdActionpotentialsatfirstnodeofRanvierIntoCNSActionpotentialsdowntheaxonOAxonterminal withneurotransmitter
General Properties of Sensory Receptors
General Properties of Sensory ReceptorsStimulusfeaturesareelectricallyencodedAparticular formof energytowhichareceptor ismostsensitiveFrequency,PopulationThresholdActionpotentialresoldStimuGeneratoxAUThresholdotentisDOET
General Properties of Sensory Receptors • Stimulus features are electrically encoded A particular form of energy to which a receptor is most sensitive Frequency, Population