组织学与胚胎学 内分泌系统 双语教学07Nerve Tissue

NERVOUSTISSUE神经组织组织学与胚胎学教研室主讲陈同强1、掌握神经组织的基本结构，神经细胞的结构特点。2、掌握突触的超微结构特点与分类。3、掌握神经纤维的结构与分类。4、熟悉神经胶质细胞、神经末梢的分类和功能。大纲要求GeneralCharacteristics

Madeupof2typesofcells:(nervecell)--structuralandfunctionalunit;--supporting,protectingandnourishingneurons.neuronneuroglialcell神经元神经胶质细胞Ⅰ.Neurons

Variousshapeandsizeincellbody:Maybespherical,fusiform,pyramidal,stellate,orirregularinshape.5-6umindiameter,thelargecanreachmorethan150um.Morethanoneprocesses,theshorteronlyseveralum,thelongestmorethan1m.神经元

Cellbodyandprocesses(and)树突轴突dendritesaxons

1.Cellbody(metabolic,trophicandintegralcenter):

Nucleus,andplasmalemma

(1).Nucleuslarge,spherical,andpale-staining;aprominent核周质/细胞质(2).(perinuclearcytoplasm)containing:

Nisslbodies

PerikaryonNeurofibrils

Perikaryon神经原纤维尼氏体

nucleolus.核仁RoughendoplasmicreticulumIndicatingactiveproteinsynthesis.Basophilicparticles,粗面内质网(RoughER/RER)+freeribosomes核糖体(a).Nisslbodies

尼氏体thinthreadsinperikaryonandprocessesvisualizedwithsilverstaininginLM.consistingofandinbundles.serveingascytoskeleton,involvedintransportationofsubstances.

(b).Neurofibrils

neurofilaments神经原纤维神经丝microtubules微管(c).OtherorganellessuchasGolgicomplex,mitochondrion,Lysosome,etc.Lipofuscinisincreasedinnumberwithage.(3).plasmalemma2.Processes–and(1).Dendrites

Oftenbranched;Oneormore/neuron,andusuallyshortandthick;Numerousfineprojections()onsurfaces;ContainingNisslbodiesandneurofibril;树突轴突dendritesaxons

dendriticspines树突棘Receivinginformationandconductingittoparentcellbody.Oneaxoneachneuron;Longandthinwithuniformdiameter;doesnotbranchprofusely;afewcollateralsperpendiculartotheaxon.轴突(2).Axons

Function:1.Conductimpulsesawayfromcellbody.

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

轴突终末

Axonterminals

轴突运输2.Axonaltransport神经递质neurotransmitters3.Classification

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

假单极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.

胆碱能Cholinergic:Noradrenergic:去甲肾上腺素能胺能Aminergic:(4).AccordingtolengthofaxonGolgitypeIneuron＆GolgitypeIIneuron1.Definition:Junctionbetweentwoneuronsorbetweenaneuronandaneffectorcellspecializedfortransmissionofimpulses.

突触Ⅱ.Synapse轴体突触Axosomaticsynapse轴棘突触Axospinoussynapse轴树突触Axodendriticsynapse2.Classification

(1).Electricalsynapse:permitdirectflowofelectricalcurrentbetweentwoneurons(gapjunction).

(2).Chemicalsynapse:useachemicalmediator(neurotransmitter)totransmitimpulsesinonedirection;3.Structureofchemicalsynapses(axonterminals)突触前成分Presynapticelement突触间隙Synapticcleft突触后成分Postsynapticelement突触小体SynapticknobSynapticvesicles(40-60nmindiameter,havingcontentofneurotransmitters,synapsinattachedtoitsmembrane),Mitochondrion(Mit),SmoothER(SER),Microtubule(Mt),Microfilament(Mf);

Presynapticmembranethickenedwithgrid,denseprojections.突触前成分(1).Presynapticelement突触小泡Synapticvesicles突触素synapsin(2).SynapticcleftExtracellularspacebetweenpre-andpostsynapticmembranes(15-30nm).(3).Postsynapticelement(theregiononthesurfaceofthereceivingneuronatthecontactpoint)Usuallydendrite(spine)orcellbody;Postsynapticmembranethickened;Specificreceptorstotheneurotransmitter.

突触间隙(2).SynapticcleftImpulsereachespresynapticelement4.Function–transmittingimpulsesinonedirection

Calciumionentering,SynapsinphosphorylatedVesiclesmovingtoandfusingwithpresynapticmembraneanddischargingneurotransmittersNeurotransmittersdiffusingacrossthecleftandcombiningwiththerecepterPermeabilityofthepostsynapticmembraneincreasingandmembranepotentialchangingGeneralfeatures

Supportingcellswithprocesses,non-excitableandnotconductimpulses;Morethanneuronsby10-50times;OnlynucleiseeninH&Estaining,smallerthanthoseofneuronsandlacknucleoli.Silverstainingshowsprocessesandcytoplasm;神经胶质细胞Ⅲ.neuroglialcellNeuroglialcellinCNS(Astrocyte,Oligodendrocyte,Microglia,Ependymalcell)Mostnumerous,bigeststar-shaped;withoval,palestainingnucleusandmanyprocesses;

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

repair,secreteneurotrophicfactor(NTF),etc;星形胶质细胞(1).Astrocytes胶质丝glialfilaments胶质原纤维酸性蛋白(glialfibrillaracidicprotein);神经营养因子neurotrophicfactor(NTF),Smallerwitharound,dark-stainingnucleus;FormingaroundaxonsintheCNS.

smallestwithairregular,darklystainednucleus;Phagocytic;Derivedfrommonocytes.少突胶质细胞(2).Oligodendrocytes髓鞘myelinsheath小胶质细胞(3).Microglia

columnarorcuboidalepithelioidcells;liningventriclesofbrainandcentralcanalofspinalcord.室管膜细胞(4).Ependymalcells2.Neurogliacellinperipheralnerveoussystem(PNS)

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

Alayerofflattenedorcuboidalcells;

Formingcapsulearoundneuronsin施万细胞(1).Schwanncells髓鞘myelinsheath神经节spinalganglia.1.inPNS

(1).Basicstructure

Axon+myelinsheath+;

NodeofRanvierPortionsdevoidofmyelinsheath;

Eachsegmentbetween2consecutivenodes-oneSchwanncell.Obliquesection神经纤维Ⅳ.NerveFibers有髓神经纤维Myelinatednervefibers神经膜

neurolemmaInternode结间体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轴突系膜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跳跃式传导Saltatoryconduction(2)UnmyelinatednervefibersImpulseconductionoccursalongtheentireaxolemma(continuousconduction)lowervelocityaxolemma:Axonplasmalemma(轴膜)P625.Nerves

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

Epineurium:FibrousCTenclosingentirenerveandalsofillingthespacebetweenbundlesofnervefibers.;Perineurium:Sheetofflattenedepithelium-likecellssurroundingeachnervebundles;

Endoneurium:ThinlayerofLCTenvelopingeachnervefiber.

EpPe(2).ConnectivetissueEp神经扫描电镜图1.Classification(1)Sensorynerveending(receptors)(2)Motornerveending(effectors)FreenerveendingsTactilecorpusclesLamellarcorpusclesMusclespindlesSomatic(motorendplate)Visceral神经末梢Ⅴ.Nerveendings(1).FreenerveendingsBranchesofnakednervefibers;Respondingtocold,heat,lighttouch,andpain.2.SensorynerveendingAbundantinepidermis,cornea,hairfollicles;(2)TactilecorpusclesFoundindermalpapillae;OvalbodieswithCTcapsule,flattenedcells