系統(tǒng)解剖學(xué)英文版教學(xué)課件：The brain stem

BrainstemLocatedbetweenthecerebrum,spinalcord(sc),anddiencephalon.Providesapathwayfortractsrunningbtwnhigherandlowerneuralcenters.Consistsof

MedullaoblongataPonsMidbrain

Thebrainstem1.MedullaoblongataMostinferiorregionofthebrainstem.Becomesthespinalcordattheleveloftheforamenmagnum.Medullarypyramid(mp,thelargemotorcorticospinaltractsDecussationofpyramid(dp,rightabovethemedulla-scjunction)Thebrainstem-VentralExternalfeaturesmpdpOliveCranialnerves:Glossopharyngealn.IXVagusn.XAccessoryn.XIHypoglossaln.XII1.Medullaoblongata:Thebrainstem-VentralExternalfeaturesIXXXIXII2.PonsBtwnthemidbrain,medulla&cerebellum.BasilarsulcusMiddlecerebellarpedunclesCranialnerves:Trigeminaln.(supralateral)Abducentn.(VI)Facialn(VII)Vestibulocochlearn.(VIII)(pontomedullaryjunction)Thebrainstem-VentralExternalfeaturesVIVIIVIII3.MidbrainLocatedbtwnthediencephalonandthepons.Twocerebralpeduncles(cerebralcruses)

contain:DescendingfibersthatgotothecerebellumviatheponsDescendingpyramidaltractCranialnerves:Oculomotorn.(III)Trochlearn.(IV)Thebrainstem-VentralExternalfeaturesIIIIV1.MedullaoblongataGraciletubercleCuneatetubercleStriatemedullaresHypoglossaltrigoneVagaltrigoneThebrainstem-DorsalExternalfeatures2.PonsDorsalmediansulcusSulcuslimitansMedialeminenceFacialcolliculusVestibularareaLocusceruleusSuperiorcerebellarpedunclesInferiorcerebellarpedunclesSuperiormedullaryvelumThebrainstem-DorsalExternalfeatures3.MidbrainSuperiorcolliculus(involvedinvisualreflexes)Inferiorcolliculius(involvedinauditoryreflexes)Brachiumofsuperiorcolliculus(tothelateralgeniculatebody)Brachiumofinferiorcolliculus(tothemedialgeniculatebody)Thebrainstem-DorsalExternalfeatures4.Rhomboidfossa:Formedbydorsalsurfaceoftheponsandtheopenpartofthemedullaoblongataboundaries:SuperiorcerebellarpeduncleInferiorcerebellarpeduncle

GraciletubercleCuneatetubercleThebrainstem-DorsalExternalfeatures5.Thefourthventricle①Location:amongcerebellum,thedorsalsurfaceofthemedullaoblongataandpons②boundaries:Floor:therhomboidfossaRoof:thecerebellumSidewalls:thecerebellarpeduncles③Communication:Inferiorly,withthecentralcanalSuperiorly,withthemesencephalic(cerebral)aqueductLaterally,withlateralforamenRoof,withmidlineforamenThebrainstem-DorsalExternalfeaturesThebrainstem-ExternalfeaturesThebrainstem-ExternalfeaturesThebrainstem-ExternalfeaturesThebrainstem-ExternalfeaturesCranialnervesI-OlfactoryII-OpticIII-OculomotorIV-TrochlearV-TrigeminalVI-AbducensVII-FacialVIII-VestibulocochlearIX-GlossopharyngealX-VagusXI-AccessoryXII-HypoglossalThebrainstem-Internalstructure1.Features:①isthelowerpartofthebrain,adjoiningandstructurallycontinuouswiththespinalcord②includesthecorticospinaltract(motor),theposteriorcolumn-mediallemniscuspathway(finetouch,vibrationsensationandproprioception)andthespinothalamictract(pain,temperature,itchandcrudetouch).③themotornucleusislocatedmedially,andsensorynucleuslaterally④providesthemainmotorandsensoryinnervationtothefaceandneckviathecranialnerves.⑤cranialnervenucleihavesevenfunctionalcomponents⑥theregionofreticularformationiswidely⑦cardiacandrespiratorycentersThebrainstem-Internalstructure2.Cranialnervenuclei(seventypes)Thebrainstem-InternalstructureGeneralsomaticmotornu.(GSE)Generalvisceralmotornu.(GVE)Specialvisceralmotornu.(SVE)Generalsomaticsensorynu.(GSA)Generalandspecialvisceralsensorynu.(GVA,Specialvisceralsensory(SVA)Specialsensorynu.Thebrainstem-Internalstructure①Generalsomaticmotornuclei(GSE)Oculomotornu.(IIIn.)Trochlearnu.(IVn.)Abducensnu.(VIn.)Hypoglossalnu.(XIIn.)innervatestriatedmusclesthatareinvolvedineyeandtonguemovementsThebrainstem-Internalstructure②Specialvisceralmotornucleitrigeminalmotornu.(V)facialnu.(VII)ambiguousnu.(IX,X,andXI)spinalaccessorynucleus(XI)

innervatemusclesthatinvolvedinchewing,makingfacialexpressions,swallowing,producingvocalsounds,andturningthehead.Thebrainstem-Internalstructure③Generalvisceralmotornucleiaccessoryoculomotornu.(Edinger-Westphal)(IIIn.)superiorsalivatorynu.(VIIn.)inferiorsalivatorynu.(IXn.)dorsalmotornu.(Xn.)

innervatesmoothmusclesandtheglandsinthehead,neckandtrunk.Thebrainstem-Internalstructure④Generalvisceralsensorynucleinucleusofsolitarytract(VII,IX,andX)receivethevisceralsensefromtheheadandneck⑤Specialvisceralsensorynucleinucleusofsolitarytract(VII,IX,andX)receivetaste.Thebrainstem-Internalstructure⑥Generalsomaticsensorynuclei:mesencephalicnucleusoftrigeminaln.pontinenucleusoftrigeminaln.spinalnucleusoftrigeminaln..receivesensefromtheskinandmucosaoftheheadThebrainstem-Internalstructure⑦Specialsomaticsensorynucleivestibularnuclei(VIIIn.)cochlearnuclei.(VIIIn.)receivethesensesofhearingandequilibrium.Thebrainstem-Internalstructure3.Othernuclei:①M(fèi)edulla:gracilenucleusandcuneatenucleus②Pons:pontinenucleus③Midbrain:nucleiofsuperiorandinferiorcolliculi;rednucleus;substantianigra

Thebrainstem-InternalstructureThebrainstem-Ascendingpathways①M(fèi)ediallemniscus:gracileandcuneatenucleigiverisetoacrossedfiberbundletoformmediallemniscus.②Spinallemniscus:continuouswiththespinothalamictractofthespinalcord.Thebrainstem-Ascendingpathways③LaterallemniscusFibersarisingfromthecontrolateralanteriorandposteriorcochlearnuclei,andsuperiorolivarynucleus,andtheipsilateralolivarynucleusformthelaterallemniscus.Thebrainstem-AscendingpathwaysThebrainstem-Ascendingpathways④TrigeminallemniscusPontinenucleusandSpinalnucleusoftrigeminaltractgiverisetoacrossedfiberbundletoformthetrigeminallemniscus.Thebrainstem-Ascendingpathways1.CorticospinaltractOriginatefrommotorneurons(BetzCell)inthecortexlateralcorticospinaltract

decussate(80%fibers)inthemedullaoblongata(pyramidaldecussation)10%fibersenterthelateralcorticospinaltractonthesamesideanteriorcorticospinaltract

(10%fibers)

traveltothespinalcorddecussateatthelevelofthespinalcordThebrainstem-Descendingpathways2.CorticonucleartractoriginatesinmotorcortexofthefrontallobeinnervatesthenucleiforcranialnervesThebrainstem-DescendingpathwaysDefinition:Adiffusenetworkofnervefibersandneuronscollectedinvariousnucleiinpartsofthebrainstemreceivesafferentaxonsfromavarietyofsourcesthissystemisimportantinmuscletone(walkingorrunning),sensoryadaptation,

visceralcontrol(breathing,heartrateandbloodpressure),controlofconsciousness(wakefulnessandsleep)byfilteringoutrepetitivestimuli.Thebrainstem-ReticularformationStructuresRaphealnu.lateralreticularforaman.MedialreticularforamanThebrainstem-Reticularformation1.CaudalmedullasectionthroughinternalarcuatefibersGracile&cuneatenuc&fascLat/Accesscuneatenuc.Spinaltrigeminaltract&nuc.OfCNVInferiorolivarynuc.MediallogitudinalfasciculusInternalarcuatefibersMediallemniscusPyramidsThebrainstem-Transversesections2.Rostralmedullathroughinferiorolivarynuclei4thventricleLat/accesscuneatenuc.InferiorcerebelpeducleSpinaltrigeminaltract&nuc.OfCNVInferiorolivarynuc.XIInuc.&CNXIIMediallogitudinalfasciculusMediallemniscusPyramidsThebrainstem-TransversesectionsXIInuc3.Caudalpons4thventricleDeepcerebelnuc.(DCN)Sup/mid/infcerebelpedunclesMediallongitudinalfasciculus(MLF)Spinaltrigeminaltract&nuc.OfCNVAnt.spinothalamictractMediallemniscusVInuc.VIIfibersPontinenucleiCorticospinaltractThebrainstem-Transversesections(DCN)VInuc.CNVIInucleus-FacialnerveMusclesoffaceThebrainstem-Transversesections4.Midpons4thv