感覺神經(jīng)系統(tǒng)癥狀GeneralPropertiesofSensorySystemsFigure10-4:Sensorypathways1.SensoryreceptorsA:Freenerveendings(pain,temperature)B:Paciniancorpuscle(pressure)C:Meissner’scorpuscle(touch)D:Musclespindle(stretch)ABCDSensoryReceptorTypesFigure10-1:SensoryreceptorsRuffini'sendingsrespondtotensionandstretchintheskin

Segmentalinnervation(dermatomes)

Peripheralinnervation

感覺傳導路由三級神經(jīng)元組成：第Ⅰ級神經(jīng)元:胞體位于脊髓后根神經(jīng)節(jié)或腦神經(jīng)感覺神經(jīng)節(jié)

第Ⅱ級神經(jīng)元:胞體位于脊髓后角細胞及延髓薄束核、楔束核或腦干腦神經(jīng)核

第Ⅲ級神經(jīng)元:胞體位于丘腦感覺接替核SpinothalamicpathwayCarriespain,temperature,touchandpressuresignals1stneuronentersspinalcordthroughdorsalroot2ndneuroncrossesoverinspinalcord;ascendstothalamus3rdneuronprojectsfromthalamustosomatosensorycortex2.淺感覺傳導路:前外側(cè)系統(tǒng)theanterolateralsystem

(先交叉，后上行)輕觸-壓覺,痛覺,溫度覺的傳入纖維↓經(jīng)后根節(jié)外側(cè)部(細纖維部分)↓進入脊髓后角并于此換元↓換元后的第Ⅱ級神經(jīng)元發(fā)出纖維↓在中央管前交叉到對側(cè)↓沿脊髓丘腦前束、脊髓丘腦側(cè)束↓上行到達丘腦感覺接替核SomaticPathwaysFigure10-9:Sensorypathwayscrossthebody’smidlineSpinothalamicPathwaySmallsensoryfibres:Pain,temperature,sometouchPrimarysomatosensorycortex(S1)ThalamusMedullaSpinalcordSpinothalamictractImpulsestransmittedtospinalcordbyMyelinatedAδnerves:fastpain(80m/s)UnmyelinatedCnerves:slowpain(0.4m/s)nociceptornociceptorAδnerveCnervespinothalamicpathwaytoreticularformationImpulsesascendtosomatosensorycortexvia:Spinothalamicpathway(fastpain)Reticularformation(slowpain)reticularformationspinothalamicpathwaythalamussomato-sensorycortexSpinothalamicdamagespinothalamicpathwayLeftspinalcordinjuryLossofsenseof:TouchPainWarmth/coldinrightleg請同學們屈起右腿右手放在桌子上閉上眼睛按指令完成動作2.2DorsalcolumnpathwayCarriesfinetouch,vibrationandconsciousproprioceptionsignals1stneuronentersspinalcordthroughdorsalroot;ascendstomedulla(brainstem)2ndneuroncrossesoverinmedulla;ascendstothalamus3rdneuronprojectstosomatosensorycortex三者的傳入沖動↓經(jīng)后根節(jié)外側(cè)部(粗纖維部分)↓進入脊髓后角↓沿同側(cè)后索上行↓抵達延髓下部在薄束核、楔束核換神經(jīng)元↓換元后的第Ⅱ級神經(jīng)元發(fā)出纖維↓交叉到對側(cè)↓沿內(nèi)側(cè)丘系↓到達丘腦感覺接替核。dorsalcloumnpathwayDorsalcolumnpathwayLargesensorynerves:Touch,vibration,two-pointdiscrimination,proprioceptionPrimarysomatosensorycortex(S1)inparietallobeThalamusMedullaMediallemniscusSpinalcordDorsalcolumnDorsalcolumnnucleiTwo-PointDiscriminationSensoryModalityFigure10-3:Two-pointdiscriminationSensoryModalityFigure10-6:LateralinhibitionDorsalcolumndamagedorsalcolumnpathwayLeftspinalcordinjuryLossofsenseof:touchproprioceptionvibrationinleftlegDorsalcolumndamageSensoryataxiaPatientstaggers;cannotperceivepositionormovementoflegsVisualclueshelpmovement由于傳導痛覺、溫度覺的傳入纖維在進入脊髓后→在進入水平的1-2個節(jié)段內(nèi)更換神經(jīng)元并交叉到對側(cè)；而傳導輕觸(-壓)覺的傳入纖維在進入脊髓后分成上行和下行纖維，分別在多個節(jié)段內(nèi)更換神經(jīng)元并交叉到對側(cè)，因而發(fā)生上述痛、溫覺受損而觸覺保留現(xiàn)象。3.頭面部的感覺傳導路：

Facialsensorypathway

觸覺、本體感覺的傳入沖動↓三叉神經(jīng)主核、中腦核中繼換元痛覺、溫度覺的傳入沖動↓三叉神經(jīng)脊束核中繼換元發(fā)出第Ⅱ級纖維→越至對側(cè)→三叉丘系→丘腦后內(nèi)側(cè)腹核Sensorysyndromes1.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,pa