Sensory SystemsAristotles five senses (plus the sixth sense equilibrium)听听视视味味嗅嗅触触Part I: The Chemical Senses Taste (gustation，味觉，味觉)Smell (olfaction，嗅觉，嗅觉)Chemical sensation is the oldest and most common of the sensory systems.The Basic Tastespoisonous substances are often bitter酸甜咸苦鲜Umami（鲜）（鲜）, unfamiliar delicious tasteKombu dashi Glutamate: Glutamate: 谷氨酸谷氨酸Inosinate:Inosinate:肌苷酸盐肌苷酸盐, ,次黄次黄( (嘌呤核嘌呤核) )苷酸盐苷酸盐Guanylate:Guanylate:鸟苷酸鸟苷酸1.Eachfoodactivatesadifferentcombinationofbasictastes2.Mostfoodshaveadistinctiveflavorasaresultoftheirtasteandsmelloccurringsimultaneously3.Othersensorymodalitiesmaycontributetoauniquefood-tastingexperience：Texture,temperature,painsensitivity Complex flavorsComplex flavorsThe Organs of TasteThe Organs of TastePapillae:乳头状突起Foliate:叶状的；层状的Vallate:杯状的Fungiform：菌状的Tastebuds:味蕾Basalcell：基底细胞Tastecell：味觉细胞Gustatoryafferentaxon：味觉传入轴突Synapse：突触Microvillus：微绒毛；微小突起物The myth of the tongue mapHnig,David(1901).ZurPsychophysikdesGeschmackssinnes.Philosophische Studien17:576623.酸甜咸苦鲜Taste Map？No!cranialnerves:脑神经Taste Map？No!ColumbiaUniversityCharlesZukerTaste receptor cells1.Notneurons2.FormsynapseswiththeendingsofgustatoryafferentaxonsnearthebottomofthetastebudTaste Receptor CellsMechanisms of Taste TransductionTastestimuli,ortastants,may(1)Directlypassthroughion channels (saltandsour),(2)bindtoandblockion channels (sour),(3)bindtoG-protein-coupled receptors inthemembranethatactivatesecondmessengersystemsthat,inturn,openionchannels(bitter,sweet,andumami).GPCRIon ChannelEncoding of taste qualities at the peripheryCentral Taste PathwaysTaste Buds (味蕾味蕾) Taste Receptor CellsCranial nerve (脑神经脑神经)Medulla（脊髓脊髓）Gustatory NucleusVentral posterior medial nucleus of thalamus(丘脑丘脑腹后内侧核腹后内侧核)Gustatory cortex (味觉味觉皮层皮层）SmellOlfactionAsmanyas100,000uniqueodorscanbediscriminateda.80%ofwhicharenoxiousb.Odorsperceivedtobenoxiousareoftendeleterious(rottingmeat,etc.).The Organs of SmellWe do not smell with our nose. Rather, we smell with a small, thin sheetof cells high up in the nasal cavity called the olfactory epithelium (嗅上皮嗅上皮)The location and structure of the olfactory epithelium.Cribriform 筛状板筛状板 Olfactory Bulb 嗅球嗅球Cribriform 筛状板筛状板 Olfactory Bulb 嗅球嗅球Olfactory Epithelium 嗅上皮嗅上皮Sizeoftheolfactoryepitheliumisproportionatetoolfactoryacuityi.Manhas10cm2ii.Doghas170cm2iii.Dogsalsohave100xreceptorspercm2Olfactory Receptor NeuronsVoltage recordings from an olfactory receptor cell during stimulationTransduction mechanisms of vertebrate olfactory receptor cellsOdor GPCR AC cAMP CNG Channel CLC ChannelTransduction mechanisms of vertebrate olfactory receptor cells1. Only receptor discussed thus far that are neurons a. Fire action potentials b. Only neurons in the nervous system that are replaced regularly throughout life Every 4-8 weeks2. Olfactory receptors are neurons and continuous with the CNS3. Ends of the olfactory receptors are mucus（粘液）（粘液） (water soluble) containing cells of the immune system and is shed every ten minutes 1) Individual with an infection (cold, flu, etc.) one sympton is a runny noise 2) Mucus is shed more frequently to protect the olfactory receptors from infection4. 500-1000 different odor binding proteins Each olfactory receptor cell expresses only one type of binding protein5. Receptor is G-protein-coupledOlfactory Receptor NeuronsCentral Olfactory PathwaysGlomerulus 嗅小球嗅小球 Central Olfactory PathwaysCentral Olfactory PathwaysOlfactoryTract:嗅束OlfactoryCortex：嗅皮层ThalamusMedialDorsalNucleus:丘脑背内侧核OrbitofrontalCortex:眶额皮层Part II：The Auditory SystemsTHE STRUCTURE OF THE AUDITORY SYSTEMAnatomy of the Cochlea耳蜗的三个管腔（前庭阶、中阶和鼓阶）耳蜗的三个管腔（前庭阶、中阶和鼓阶）Cochlea Hair CellsPiotr Kazmierczak (Trends in Neurosciences, 2012)Hair cells and their mechanotransduction machineryDepolarization of a hair cellTip-LinkSensory TRPs(Transient Receptor Channel)Part III: The Somatic Sensory SystemSomatic sensation enablesour body to feel, to ache, to chill, and to know what its parts are doingTouchPainTemperatureSensation of touchReceptive Field感受野感受野 Mechanoreceptors of the SkinMolecules that govern touch sensitivity in mammalian somatosensory neuronsTouch-sensitive axons in the spinal cord背根节神经元背根节神经元dorsal root ganglion cell （DRG cell）背柱-内侧丘系The dorsal columnmedial lemniscal pathwayThe Sensory Homunculus is an image that shows the relative amount of cerebral cortex surface area given over to processing the different sensory inputs and motor outputs of human nervous systemSensory Homunculus PAINPainisthefeeling,ortheperception,ofirritating,sore,stinging,aching,throbbing,miserable,orunbearablesensationsarisingfromapartofthebody.Nociception (痛觉)isthesensoryprocessthatprovidesthesignalsthattriggerpain.mechanical nociceptors,selectiveresponsestostrongpressure;thermal nociceptors, selectiveresponsestoburningheatorextremecold;chemical nociceptors, selectiveresponsestohistamineandotherchemicals;polymodal nociceptorsrespondtomechanical,thermal,andchemicalstimuli.Nociceptors and the Transduction of Painful StimuliPeripheral chemical mediators of pain and hyperalgesiaHyperalgesia 痛觉过敏痛觉过敏舒缓激肽舒缓激肽bradykinin前列腺素前列腺素prostaglandinsP 物质物质substance PThe spinothalamic pathwayThe Endogenous OpiatesOpiate 鸦片剂鸦片剂,麻醉剂麻醉剂Opiumandtheiranaloguesincludingmorphine,codeine,andheroinareusedandabusedwidelytoday,inmostculturesoftheworld.Opioidsproduceprofoundanalgesiawhentakensystemically.Theycanalsoproducemoodchanges.Opioidreceptorsendogenousmorphine-likesubstancesEndorphins:痛觉缺失痛觉缺失ThermoreceptorsThermoreceptor TRP channels tunedto detect different temperaturesAdaptations of thermoreceptors.Thank You!LIJUN KANGINSTITUTE OF NEUROSCIENCEZHEJIANG UNIVERSITYKANGLIJUNZJU.EDU.CN2014.05.23