分子細胞生物學課件：14神經(jīng)組織

NervousTissueWhatabeautifulworld!NervousTissueneurones：neuroglia：Receivestimuli,ConductelectricalimpulseEndocrineSupporting

cellsOutlineNeuron:章心怡Synapse：周佩Neuroglia：徐伊琳Nervefiber：何紫儀NerveEnding：張子琛BasicNeuronetypesBipolarneuronePseudo-unipolarneuroneMultipolarneuronesoma(cellbody)：variationinsizeandshape;

metaboliccenteraxon:

single,arisefromtheAxonhillockterminateontheotherneuronsoreffectororgans(nerveending)

generateandconductactionpotencial(electricalimpulse)dendrite:oneormore,highlybranched(dendritic

spine),taperingprocessesmajorsitesofinformationinputThebasicstructureofNeurone1、soma(cellbody)：membrane：excitable，containingionchannelandneurotransmitterreceptorsneucleus：palestained,centrallylocated,nucleolusprominentcytoplasm(perikaryon)：Nisslebody,

Neurofibril,etc

NisslbodyLM:clumpsofhighlybasophiliccytoplasmmaterial

EM:abundantRERandfreeribosomes

Functions：proteinsysthesis(enzymes,structualproteins)Neurofibril

LM:argyrophilic,interlacedintonetwork

presentinpeikaryon,dentritesandaxonEM:microfilamentsandmicrotubulesFuctions:maintainthecellshape,axonaltransport,FoundinperikaryonanddentritesbutisnotpresentinaxonhillockoraxonAxonaltransportAnterogradeRetrograde(eg:neurotransmitter)(eg:somevirusesinfection)NeurondendriteNisslebodyNeurofibrilNodeofRanvieroligodendrocyteCNSPNSSchwanncellMyelinsheathMyelinsheathTerminalendAxonhillockMotorneuronsofspinalcordthesitesofintercommunicationbetweenneuronsorbetweenneuronsandeffectorcells

twotypesofsynapse:

chemicalsynapse:conductedbyneurotransmitter，onewayconduction

electricalsynapse:gapjunction,conductedbyion,onewayorbothwaysconduction

synapseAxodendritic:“standard”Axosomatic:AxoaxonicsynapsesAxospinicThemostcommonsitesforsynapsesdendriteaxonaxosomaticAxodendriticaxospinicaxoaxonicchemicalsynapseLM：synapticknob（presynapticswellings）EMpre-synapticelementSynapticvesicles(NeuroTransmitter)Pre-synapticmembranemitochondriaSynapticcleft:enzymestoinactivatedNTbetweensuccessiveactionpotencialPost-synapticelementPost-synapticmembraneReceportsofNTIonicchannelssynapticknobSynapticvesiclespresynapticmembraneSynapticcleftpostsynapticmembraneaxosomaticAxodendriticaxospinicsynapsesynapseNeuroglialmorenumerousthanneuroneshighlybranchedcellsprovidingbothmechanicalandmetabolicsupportofneuronesAstrocytesOligodendrocytesMicrogliaEpendymalcellsSchwanncellSatellitecell(capusulecell)CNS:PNS:NervoussystemCentralNervousSystem:PeripheralNervousSystemspinalcordbrainnervegangliaAstrocyte:starshaped;haveprolific,long,highlybranchedprocesses

perivascularfeet(terminalexpansionsofprocesses)Fibrousastrocytes：inwhitematter,lessprocesses,moremicrofilamentsProtoplasmicastrocytes：ingreymatter,moreprocesses,lessmicrofilamentsFunctions:protection(bloodbrainbarrierformation)repairtissuedamage(scarformation)AstrocytesFibrousastrocytesProtoplasmicastrocytescapilaryPerivascularfeetFibrousastrocytesProtoplasmicastrocytesbloodbrainbarrierFuctions：maintaintheenviromentofthebraininasteadystatetheendothelialcellsofcapillaries(tightjunctions,limitedmethodsoftranscellulartransport)intactbasementmembraneperivascularfeetoftheastrocytesSmalllipid-solublemoleculescrossthebarriereasily(eg.diamorphine)HydrophilicmoleculesrelyonspecifictransportersystemsBloodbrainbarrierEpithelialcellTightjunctionBasementmembranePerivascularfeetofastrocytepericyteBrainischaemia,braintumors,haemorrhageorinfections…maybreakdownthebloodbrainbarrieroligodendrocyte

smallnumberofshort,branchedprocessesareresponsibleformyelinationofaxonsintheCNS

microglias

amemberofmononuclearphagocyticsystemependymalcellsformthesimplecuboidalepitheliumliningoftheventriclesandspinalcanalmostofthemhaveciliaontheirsurfacescontributetheflowofcerebrospinalfluidSchwanncellareresponsibleforthemyelinationofaxonsinthePNSSatellitecell(capsularcell）

surroundthenervecellbodiesinganglia

NeurogliainPNS:NervefibersaxonsneurogliaCNS：oligodentrocytesPNS：Schwanncells+MyelinatednervefibersNon-myelinatednervefibersDependonthemyelinationMyelinsheathmyelinatednervefiberinPNSAxonsarewrappedbyavariablenumberofconcentriclayersoftheSchwanncellplasmamembraneformingmyelinsheathplasmamembrane:myelin(phospholipid)andproteinEM:manyconcentriclayersofplasmamembraneinsulationNodeofRanvierMyelinsheathSchwanncellnucleusAxonIncisureofmyelinProteinnetwork(Schmidt-Lantermannincisure)MyelinationofnervefibersinPNSMesaxonMyelinatednervefiberMyelinatednervefiber2.MyelinatednervefiberintheCNSOligodendrocytesareresponsibleforthemyelinationAxonoligodentrocyteMyelinsheathNodeofRanvier

Non-myelinatednervefiber1、PNS

axonsareembeddedintothecytoplasmaoftheSchwanncells.2、CNS

nakedaxons

SchwanncellAxonNon-myelinatednervefiberFunctionofnerverfiber：condutionofnerveimpulse(actionpotencial)Myelinatednervefiber：saltatoryconduction,muchfasterNon-myelinatednervefiber：continuousconductionContinuousconductionSaltatoryconductionWhatwillhappenifdemyelinationoccur？Multiple-sclerosis:demyelinationoccursintheCNS

Guillain-BarresyndromedemyelinationoccursintheperipheralnervesNerveendingsFreenerveending：responsibleforcutaneouspainandtemperature

Tactilecorpuscle:lightdiscriminartorytouchLamellarcorpuscle:pressure,coarsetouch,vibrationandtensionMusclespindle:proprioceptorTerminalendsofnervefiber（+）non-nervoustissuesensorynerveendingsEncapsulatednerveending:

FreenerveendingsTactilecorpuscleMeissner’scorpusclelocatedindermalpapillaeofskinresponsibleforlightd