感觉系统症状1课件

感觉神经系统症状苗旺GENERALPROPERTIESOFSENSORYSYSTEMSFigure10-4:Sensorypathways1.SENSORYRECEPTORSA:Freenerveendings(pain,temperature)B:Paciniancorpuscle(pressure)C:Meissner’scorpuscle(touch)D:Musclespindle(stretch)ABCDRuffini'sendingsrespondtotensionandstretchintheskin

SEGMENTALINNERVATION(DERMATOMES)

PERIPHERALINNERVATION

感觉传导路由三级神经元组成：第Ⅰ级神经元:胞体位于脊髓后根神经节或脑神经感觉神经节

第Ⅱ级神经元:胞体位于脊髓后角细胞及延髓薄束核、楔束核或脑干脑神经核

第Ⅲ级神经元:胞体位于丘脑感觉接替核2.浅感觉传导路:前外侧系统theanterolateralsystem

(先交叉，后上行)轻触-压觉,痛觉,温度觉的传入纤维↓经后根节外侧部(细纤维部分)↓进入脊髓后角并于此换元↓换元后的第Ⅱ级神经元发出纤维↓在中央管前交叉到对侧↓沿脊髓丘脑前束、脊髓丘脑侧束↓上行到达丘脑感觉接替核SOMATICPATHWAYSFigure10-9:Sensorypathwayscrossthebody’smidlineImpulsestransmittedtospinalcordbyMyelinatedAδnerves:fastpain(80m/s)UnmyelinatedCnerves:slowpain(0.4m/s)nociceptornociceptorAδnerveCnervespinothalamicpathwaytoreticularformationImpulsesascendtosomatosensorycortexvia:Spinothalamicpathway(fastpain)Reticularformation(slowpain)reticularformationspinothalamicpathwaythalamussomato-sensorycortexSPINOTHALAMICDAMAGEspinothalamicpathwayLeftspinalcordinjuryLossofsenseof:TouchPainWarmth/coldinrightleg2.2DORSALCOLUMNPATHWAYCarriesfinetouch,vibrationandconsciousproprioceptionsignals1stneuronentersspinalcordthroughdorsalroot;ascendstomedulla(brainstem)2ndneuroncrossesoverinmedulla;ascendstothalamus3rdneuronprojectstosomatosensorycortex三者的传入冲动↓经后根节外侧部(粗纤维部分)↓进入脊髓后角↓沿同侧后索上行↓抵达延髓下部在薄束核、楔束核换神经元↓换元后的第Ⅱ级神经元发出纤维↓交叉到对侧↓沿内侧丘系↓到达丘脑感觉接替核。DorsalcolumnpathwayLargesensorynerves:Touch,vibration,two-pointdiscrimination,proprioceptionPrimarysomatosensorycortex(S1)inparietallobeThalamusMedullaMediallemniscusSpinalcordDorsalcolumnDorsalcolumnnucleiTWO-POINTDISCRIMINATIONSENSORYMODALITYFigure10-3:Two-pointdiscriminationDORSALCOLUMNDAMAGEdorsalcolumnpathwayLeftspinalcordinjuryLossofsenseof:touchproprioceptionvibrationinleftlegDORSALCOLUMNDAMAGESensoryataxiaPatientstaggers;cannotperceivepositionormovementoflegsVisualclueshelpmovementSENSORYSYNDROMES1.Peripheralnerve: accordingtothedistributionareaoftheaffectednervePolyneuropathy: glove–stockingdistribution, morepronaunceddistaly,moreonthelowerextremitiesDorsalrootgangliaorradicularlaesions: segmental,localisedtodermatomesSENSORYSYNDROMES2.Spinalcord: -completecordlesion -hemisectionofspinalcord:Brown–Sequardsyndrome -centralcordlesion(Syringomyelia,dissociatedsensoryloss:lossofpainandtemperature,preservationofproprioception) -posteriortractlesion(funicularmyelosis:lossofproprioception,ataxia) -conuslaesion(sensorylossofsacralarea,“saddleanaesthesia)Brainstem:WallenbergsyndromeThalamus:Dejerine–Roussysyndrome(contralateralhemihypaesthesia,ataxia,pain)Sensorycortex:contralateralhemihypa