SENSORY PATHWAY-感觉通路-神经解剖学课件-华西医大.ppt

SensorFPawaDrWangfanAscendingpathwayAscending(somatosensory)pathwaycarryImpulsesfrompain,thermaltactile,muscleandjcintreceptorstothebrain.Someofthisinformationfinallyreaches2consciouslevel(thecerebralcortex)whilesomeisdestinedforSubconsciouscentres(e.g.thecerebellum山【【nneeSpinocerebellarpathwayisdestinedforsubconscious(unconscious)centresThesomatosensorysystemincludesmultipletypesofSensationfromthebody-lighttouch,pain,pressure,temperature,finetouchandjointandmusclepositionsense(alsocalledproprioception)-Generally,therearethreetypesofsensation.Thefirstsensationiscalleddiscriminativetouch(finetouch),whichincludestouch,pressure,andvibrationperception,andenablesusto“read“raisedletterswithourfingertips,oridescribethershapeandtexXtureofanobjectwithoutseeingit.Thesecondsensationispainandtemperature,whichisjustwhatitsoundslike,andalsoincludesthesensationsofitchandtickle.Thethirdsensationiscalledproprioception,andincludesreceptorsforwhathappensbelowthebodysurface:musclestretch,jointposition,tendontension,andsoon.AscendingpathwaythatcarryinformationtoaconsciouslevelSharecertaincommoncharacteristics:1.thereisasequenceofthreeneuronesbetweentheperipheralreceptorandthecerebralcortex.spinothalamictracts.|Spinothalamiclemmiscusfasciculusgracilisandfasciculus止_cuneatusTrigefhinothalami】′lemmiscusMediallemmiscus2.thefirstneurone(frist-orderneuroneorprimaryafferentneurone)entersthespinalcordthroughthedorsalrootofaspinalnerveanditscellbodyliesinthedorsalrootganglion.3.Thesecond-orderneuroneshasitscelLbodyinthespinalcordorImedullaoblongataIts2XOnCrOSSeSOVer(decussates)totheoppositesideoftheCNSandascendstothethalamus,whereitterminatesuponthethirdneurone.丨乒真ethird-orderneuroneshasitscellbodyinthalamus.ItsaxonpaSsestothesomatosensorycortexoftheparietallobeofthecerebralhemisphere.5.AnysensorySystemgoingtothecerebralcortexw训havetocrossover「at「somePoint,becausethecerebralCortexOperateSOnacontralateral(oppositeside)basis.ThediscriminativetouchS又stemCTOSSeShighlevel--inthemedulla.ThePainSystemcrosseslowlevel--inthespinalcord.TwomainAscendingpathwaysinthespinalcord:thedorsalposteriorjcolumn(thefasciculusgracilisandfasciculuscuneatus)andthespinaothalamictracts.Twomaintractsystemsinthebrainstem:1.laterallemmiscus(Auditorypathway)2.trigeminallemmiscus(Thesuperficialanddeepsensorypathwayofheadandface)EThecentralvisualpathway。