SensorySystemsAristotle'sfivesenses(plusthesixthsenseequilibrium)聽視味嗅觸PartI:TheChemicalSenses

Taste(gustation，味覺)Smell(olfaction，嗅覺)Chemicalsensationistheoldestandmostcommonofthesensorysystems.TheBasicTastespoisonoussubstancesareoftenbitter酸甜咸苦鮮Umami（鮮）,unfamiliardelicioustasteKombudashiGlutamate:谷氨酸Inosinate:肌苷酸鹽,次黃(嘌呤核)苷酸鹽Guanylate:鳥苷酸Eachfoodactivatesadifferentcombinationofbasictastes2.Mostfoodshaveadistinctiveflavorasaresultoftheirtasteandsmelloccurringsimultaneously3.Othersensorymodalitiesmaycontributetoauniquefood-tastingexperience：Texture,temperature,painsensitivity…ComplexflavorsTheOrgansofTastePapillae:乳頭狀突起Foliate:葉狀的；層狀的Vallate:杯狀的Fungiform：菌狀的Tastebuds:味蕾Basalcell：基底細胞Tastecell：味覺細胞Gustatoryafferentaxon：味覺傳入軸突Synapse：突觸Microvillus：微絨毛；微小突起物ThemythofthetonguemapH?nig,David(1901).

"ZurPsychophysikdesGeschmackssinnes".

PhilosophischeStudien

17:576–623.酸甜咸苦鮮TasteMap？No!cranialnerves:腦神經TasteMap？No!ColumbiaUniversityCharlesZukerTastereceptorcells1.Notneurons2.FormsynapseswiththeendingsofgustatoryafferentaxonsnearthebottomofthetastebudTasteReceptorCellsMechanismsofTasteTransductionTastestimuli,ortastants,mayDirectlypassthroughionchannels(saltandsour),bindtoandblockionchannels(sour),bindtoG-protein-coupledreceptorsinthemembranethatactivatesecondmessengersystemsthat,inturn,openionchannels(bitter,sweet,andumami).GPCRIonChannelEncodingoftastequalitiesattheperipheryCentralTastePathwaysTasteBuds(味蕾)TasteReceptorCellsCranialnerve(腦神經)Medulla（脊髓）GustatoryNucleusVentralposteriormedialnucleusofthalamus(丘腦腹后內側核)Gustatorycortex(味覺皮層）SmellOlfactionAsmanyas100,000uniqueodorscanbediscriminateda.80%ofwhicharenoxiousb.Odorsperceivedtobenoxiousareoftendeleterious(rottingmeat,etc.).TheOrgansofSmellWedonotsmellwithournose.Rather,wesmellwithasmall,thinsheetofcellshighupinthenasalcavitycalledtheolfactoryepithelium(嗅上皮)Thelocationandstructureoftheolfactoryepithelium.Cribriform篩狀板OlfactoryBulb嗅球Cribriform篩狀板OlfactoryBulb嗅球OlfactoryEpithelium嗅上皮Sizeoftheolfactoryepitheliumisproportionatetoolfactoryacuityi.Manhas10cm2ii.Doghas170cm2iii.Dogsalsohave100xreceptorspercm2OlfactoryReceptorNeuronsVoltagerecordingsfromanolfactoryreceptorcellduringstimulationTransductionmechanismsofvertebrateolfactoryreceptorcellsOdorGPCRACcAMPCNGChannelCLCChannelTransductionmechanismsofvertebrateolfactoryreceptorcells1.Onlyreceptordiscussedthusfarthatareneuronsa.Fireactionpotentialsb.OnlyneuronsinthenervoussystemthatarereplacedregularlythroughoutlifeEvery4-8weeks2.OlfactoryreceptorsareneuronsandcontinuouswiththeCNS3.Endsoftheolfactoryreceptorsaremucus（粘液）

(watersoluble)

containingcellsoftheimmunesystemandisshedeverytenminutes1)Individualwithaninfection(cold,flu,etc.)onesymptonisarunnynoise2)Mucusisshedmorefrequentlytoprotecttheolfactoryreceptorsfrominfection4.500-1000differentodorbindingproteinsEacholfactoryreceptorcellexpressesonlyonetypeofbindingprotein5.ReceptorisG-protein-coupledOlfactoryReceptorNeuronsCentralOlfactoryPathwaysGlomerulus嗅小球

CentralOlfactoryPathwaysCentralOlfactoryPathwaysOlfactoryTract:嗅束OlfactoryCortex：嗅皮層ThalamusMedialDorsalNucleus:丘腦背內側核OrbitofrontalCortex:

眶額皮層PartII：TheAuditorySystemsTHESTRUCTUREOFTHEAUDITORYSYSTEMAnatomyoftheCochlea耳蝸的三個管腔（前庭階、中階和鼓階）CochleaHairCellsPiotrKazmierczak(TrendsinNeurosciences,2012)HaircellsandtheirmechanotransductionmachineryDepolarizationofahaircellTip-LinkSensoryTRPs(TransientReceptorChannel)PartIII:TheSomaticSensorySystemSomaticsensationenablesourbodytofeel,toache,tochill,andtoknowwhatitspartsaredoingTouchPainTemperature…SensationoftouchReceptiveField感受野

MechanoreceptorsoftheSkinMoleculesthatgoverntouchsensitivityinmammaliansomatosensoryneuronsTouch-sensitiveaxonsinthespinalcord背根節(jié)神經元dorsalrootganglioncell（DRGcell）

背柱-內側丘系Thedorsalcolumn–mediallemniscalpathwayTheSensoryHomunculusisanimagethatshowstherelativeamountofcerebralcortexsurfaceareagivenovertoprocessingthedifferentsensoryinputsandmotoroutputsofhumannervoussystemSensoryHomunculusPAINPainisthefeeling,ortheperception,ofirritating,sore,stinging,aching,throbbing,miserable,orunbearablesensationsarisingfromapartofthebody.Nociception(痛覺)isthesensoryprocessthatprovidesthesignalsthattriggerpain.mechanicalnociceptors,selectiveresponsestostrongpressure;thermalnociceptors,selectiveresponsestoburningheatorextremecold;chemicalnociceptors,selectiveresponsestohistamineandotherchemicals;polymodalnociceptorsrespondtomechanical,thermal,andchemicalstimuli.NociceptorsandtheTransductionofPainfulStimuliPeripheralchemicalmediators