NERVOUSTISSUE神經(jīng)組織組織學(xué)與胚胎學(xué)教研室主講陳同強1、掌握神經(jīng)組織的基本結(jié)構(gòu)，神經(jīng)細(xì)胞的結(jié)構(gòu)特點。2、掌握突觸的超微結(jié)構(gòu)特點與分類。3、掌握神經(jīng)纖維的結(jié)構(gòu)與分類。4、熟悉神經(jīng)膠質(zhì)細(xì)胞、神經(jīng)末梢的分類和功能。大綱要求GeneralCharacteristics

Madeupof2typesofcells:(nervecell)--structuralandfunctionalunit;--supporting,protectingandnourishingneurons.neuronneuroglialcell神經(jīng)元神經(jīng)膠質(zhì)細(xì)胞Ⅰ.Neurons

Variousshapeandsizeincellbody:Maybespherical,fusiform,pyramidal,stellate,orirregularinshape.5-6umindiameter,thelargecanreachmorethan150um.Morethanoneprocesses,theshorteronlyseveralum,thelongestmorethan1m.神經(jīng)元

Cellbodyandprocesses(and)樹突軸突dendritesaxons

1.Cellbody(metabolic,trophicandintegralcenter):

Nucleus,andplasmalemma

(1).Nucleuslarge,spherical,andpale-staining;aprominent核周質(zhì)/細(xì)胞質(zhì)(2).(perinuclearcytoplasm)containing:

Nisslbodies

PerikaryonNeurofibrils

Perikaryon神經(jīng)原纖維尼氏體

nucleolus.核仁RoughendoplasmicreticulumIndicatingactiveproteinsynthesis.Basophilicparticles,粗面內(nèi)質(zhì)網(wǎng)(RoughER/RER)+freeribosomes核糖體(a).Nisslbodies

尼氏體thinthreadsinperikaryonandprocessesvisualizedwithsilverstaininginLM.consistingofandinbundles.serveingascytoskeleton,involvedintransportationofsubstances.

(b).Neurofibrils

neurofilaments神經(jīng)原纖維神經(jīng)絲microtubules微管(c).OtherorganellessuchasGolgicomplex,mitochondrion,Lysosome,etc.Lipofuscinisincreasedinnumberwithage.(3).plasmalemma2.Processes–and(1).Dendrites

Oftenbranched;Oneormore/neuron,andusuallyshortandthick;Numerousfineprojections()onsurfaces;ContainingNisslbodiesandneurofibril;樹突軸突dendritesaxons

dendriticspines樹突棘Receivinginformationandconductingittoparentcellbody.Oneaxoneachneuron;Longandthinwithuniformdiameter;doesnotbranchprofusely;afewcollateralsperpendiculartotheaxon.軸突(2).Axons

Function:1.Conductimpulsesawayfromcellbody.

(conicalregion);DevoidofNisslbodies;(buttons)containvesicleswithneurotransmittersinthem;軸丘Axonhillock

軸突終末

Axonterminals

軸突運輸2.Axonaltransport神經(jīng)遞質(zhì)neurotransmitters3.Classification

(1).AccordingtonumberofprocessesPseudounipolarfoundinspinalganglia;Bipolar:presentincochlearandvestibularganglia,retina,olfactory,etc;Multipolor:majorityofneurons.

假單極Pseudounipolar：(2).AccordingtofunctionSensoryorafferent;Motororefferent;Interneurons:toformcomplexfunctionalcircuits,toaccountfor99%ofneuronsinthebody.(3).AccordingtoneurotransmitterreleasedCholinergic:acetylcholine(Ach);Noradrenergic:norepinephrine(NE)Aminergic:dopamine(DA),hydroxytryptamine;Aminoacidnergic:glycine,glutamicacid,etc

Peptidergic:polypeptidessuchassubstanceP,vasopressin,etc.

膽堿能Cholinergic:Noradrenergic:去甲腎上腺素能胺能Aminergic:(4).AccordingtolengthofaxonGolgitypeIneuron＆GolgitypeIIneuron1.Definition:Junctionbetweentwoneuronsorbetweenaneuronandaneffectorcellspecializedfortransmissionofimpulses.

突觸Ⅱ.Synapse軸體突觸Axosomaticsynapse軸棘突觸Axospinoussynapse軸樹突觸Axodendriticsynapse2.Classification

(1).Electricalsynapse:permitdirectflowofelectricalcurrentbetweentwoneurons(gapjunction).

(2).Chemicalsynapse:useachemicalmediator(neurotransmitter)totransmitimpulsesinonedirection;3.Structureofchemicalsynapses(axonterminals)突觸前成分Presynapticelement突觸間隙Synapticcleft突觸后成分Postsynapticelement突觸小體SynapticknobSynapticvesicles(40-60nmindiameter,havingcontentofneurotransmitters,synapsinattachedtoitsmembrane),Mitochondrion(Mit),SmoothER(SER),Microtubule(Mt),Microfilament(Mf);

Presynapticmembranethickenedwithgrid,denseprojections.突觸前成分(1).Presynapticelement突觸小泡Synapticvesicles突觸素synapsin(2).SynapticcleftExtracellularspacebetweenpre-andpostsynapticmembranes(15-30nm).(3).Postsynapticelement(theregiononthesurfaceofthereceivingneuronatthecontactpoint)Usuallydendrite(spine)orcellbody;Postsynapticmembranethickened;Specificreceptorstotheneurotransmitter.

突觸間隙(2).SynapticcleftImpulsereachespresynapticelement4.Function–transmittingimpulsesinonedirection

Calciumionentering,SynapsinphosphorylatedVesiclesmovingtoandfusingwithpresynapticmembraneanddischargingneurotransmittersNeurotransmittersdiffusingacrossthecleftandcombiningwiththerecepterPermeabilityofthepostsynapticmembraneincreasingandmembranepotentialchangingGeneralfeatures

Supportingcellswithprocesses,non-excitableandnotconductimpulses;Morethanneuronsby10-50times;OnlynucleiseeninH&Estaining,smallerthanthoseofneuronsandlacknucleoli.Silverstainingshowsprocessesandcytoplasm;神經(jīng)膠質(zhì)細(xì)胞Ⅲ.neuroglialcellNeuroglialcellinCNS(Astrocyte,Oligodendrocyte,Microglia,Ependymalcell)Mostnumerous,bigeststar-shaped;withoval,palestainingnucleusandmanyprocesses;

Containglialfilaments(glialfibrillaracidicprotein);Twoformsofastrocytes:fibrousandprotoplasmic;Support&separateneurons,

repair,secreteneurotrophicfactor(NTF),etc;星形膠質(zhì)細(xì)胞(1).Astrocytes膠質(zhì)絲glialfilaments膠質(zhì)原纖維酸性蛋白(glialfibrillaracidicprotein);神經(jīng)營養(yǎng)因子neurotrophicfactor(NTF),Smallerwitharound,dark-stainingnucleus;FormingaroundaxonsintheCNS.

smallestwithairregular,darklystainednucleus;Phagocytic;Derivedfrommonocytes.少突膠質(zhì)細(xì)胞(2).Oligodendrocytes髓鞘myelinsheath小膠質(zhì)細(xì)胞(3).Microglia

columnarorcuboidalepithelioidcells;liningventriclesofbrainandcentralcanalofspinalcord.室管膜細(xì)胞(4).Ependymalcells2.Neurogliacellinperipheralnerveoussystem(PNS)

FormingaroundaxonsinPNS;Secretingneurotrophicfactors(NTF),Guidingnerveregeneration.(2).Satellitecells(capsularcells)

Alayerofflattenedorcuboidalcells;

Formingcapsulearoundneuronsin施萬細(xì)胞(1).Schwanncells髓鞘myelinsheath神經(jīng)節(jié)spinalganglia.1.inPNS

(1).Basicstructure

Axon+myelinsheath+;

NodeofRanvierPortionsdevoidofmyelinsheath;

Eachsegmentbetween2consecutivenodes-oneSchwanncell.Obliquesection神經(jīng)纖維Ⅳ.NerveFibers有髓神經(jīng)纖維Myelinatednervefibers神經(jīng)膜

neurolemmaInternode結(jié)間體andnerve(2).MyelinsheathLM:spongelike(H&E),Black(OsO4).Themyeliniscomplexoflipids(80%)andproteins,lipidsaredissolvedoutbylipidsolvents.InEMitshowsaseriesofconcentricallyarrangedlightanddarklamellae

Incisureofmyelin/Schmidt-Lantermanincisure:cone-shapedclefts(containcytoplasmoftheSchwanncell).IncisureofmyelinDuringthedevelopmentofthemyelinsheath,theschwanncellfirstfixestothesurfaceoftheaxonandaxonpenetratesintothegrooveoftheschwanncellcytoplasm.Theedgesofthegroovefusetogethertoforma.Themesaxonstarttorotatearoundtheaxon,thenformmyelinlamella.Formation軸突系膜mesaxon2.MyelinatednervefibersinCNS

SimilartoMyelinatednervefibersinPNS;Noneurolemma,noincisuresofmyelin;DifferenceofmyelinatednervefiberinPNSandinCNS1.Themyelin-formingcellsinperipheralnervoussystemaretheSchwanncells,butinthecentralnervoussystemareoligodendrocytes.2.InPNS,oneSchwanncellformsoneinternodalsegment,butinCNSoneoligodendrocyteformsseveralinternodalsegments.3.InPNS,eachmyelinatedfiberisdelimitedbyabasallamina,andsuchfibersareseparatedfromeachotherbyconnectivetissueoftheendoneurium.However,intheCNS,thereisnobasallaminaorendoneuriumsurroundingmyelinatednervefibers.4.Mesaxonsarepresentinperipheralmyelinatednervefibers,butnotinthemyelinatednervefibersoftheCNS.Myelinsheathisformedbyprocessesofoligodendrocyteswhichcanformseveralinternode.3.Unmyelinatednervefibers

(1)PNSThinaxons(singleorgroup)indentedintoSchwanncells;NomyelinsheathandnodesofRanvier.(2)CNSFreeaxonsamongothermyelinatednervefibersandglialprocesses

:Myelinsheathservingasaninsulator,thenerveimpulsesjumpfromnodetonodeacrossinternodeandconductionspeedareenhanced;Thickeraxon→thickermyelinsheathandlongerinternode→greaterconductionvelocity.(1)Myelinatednervefibers:4.Functionalroleofnervefiber跳躍式傳導(dǎo)Saltatoryconduction(2)UnmyelinatednervefibersImpulseconductionoccursalongtheentireaxolemma(continuousconduction)lowervelocityaxolemma:Axonplasmalemma(軸膜)P625.Nerves

–branching,cord-likestructureswhichextendoutwardsfromthebrainascranialnerves,andfromthespinalcordasspinalnerves,toreachalmosteverypartofthebody.Becomposedofnervefibersandconnectivetissue.(1).NervefibersNervefibersMixed,bothmyelinatedandunmyelinated,sensoryandmotor.

Epineurium:FibrousCTenclosingentirenerveandalsofillingthespacebetweenbundlesofnervefibers.;Perineurium:Sheetofflattenedepithelium-likecellssurroundingeachnervebundles;

Endoneurium:ThinlayerofLCTenvelopingeachnervefiber.

EpPe(2).ConnectivetissueEp神經(jīng)掃描電鏡圖1.Classification(1)Sensorynerveending(receptors)(2)Motornerveending(effectors)FreenerveendingsTactilecorpusclesLamellarcorpusclesMusclespindlesSomatic(motorendplate)Visceral神經(jīng)末梢Ⅴ.Nerveendings(1).FreenerveendingsBranchesofnakednervefibers;Respondingtocold,heat,lighttouch,andpain.2.SensorynerveendingAbundantinepidermis,cornea,hairfollicles;(2)TactilecorpusclesFoundindermalpapillae;OvalbodieswithCTcapsule,flattenedcells