Morfologické rysy
Pozorováno, converelectronmicroscope, thereretwolayersOfMembranesatthesypsapse, nazývá se PressynapticMembraneandthepostsynapticMembran, ssynapticcleftbeenthetwombrany.Proto asynapseiscomposeofTHreeParts: ThePresynapticmembrane, Thesynapticcleft athepostsynapticmembran.ThethicknessOftheFrontMandThebackFilmisgenerallyOnlyAbout7nm, athegapisabout20nm.TheAxoplasmneartheanterimMbranecontainsMitochondriaandsynapticvesicles, thediaMeterEfTheVesiclesIs30-60nm, který je uchovává.
Přenos
OnTheInnersideofTheanteriOrMembran, thesisIsAveSicleFenceformedByDenseProtrusionsAndgrids.TheGapContainsSynapticvesicle, který mayhaveaguidingSynapse.THECONTACTTHTHONTACTVESIDICKICES WiththeanteriOrMbranePromoteSeleaseofTransMitterSynapticvesicles.Whentheimpulsefromthepresynapticneuronreachesthesynaptosome,thetransmitterinthevesicleisreleasedfromtheanteriormembrane,entersthesynapticcleft,andactsonthepostsynapticmembrane;ifthiseffectislargeenough,Itcancauseexcitatoryorinhibitoryresponsesofpostsynapticneurons.
ThisAntoterwayofsynapTransmisionSonomineTransMittersinneurony.ThisPeofneuronhasmanybranchesatheendoftheaxon, andthereareAlargenemumberOfnodularvaricosebodieSonthebranches.VaricoSecontainSalarGenumberOfvesiclesInThebody, který se vyskytl.Nicméně, VaricoseboDiesRenotindiRectContactWithPostSynapticneuronsoreffectorCells, butareintheirvicinity.WHentHenerveimSereacheSthevaricoSebody, thetransMitterIsResedFomtHevaricoSosebandDiffuseStothereceptorsofthThePost-SynapticCellMembranetoproduceAtransmiseFectEftect.ThismodeofTransmisionExistsBothinthecentralRervsSystemAndonthesympaticPostGanglionicfibers.
Charakteristiky přenosu
1.Jednosměrná přenos
Synaptický přenosCanonlybetransMitedbypresynapticneuronsonAlongaxonstopost-synapticneurons, ireversibletransmise.ProtožeOnlyTheranynapticMembRenecanreleasethetRansmiter.Proto TheExcitementCanonlybetransMitedFromTheafferentNeuron, prostřednictvíminterneuronu a od nich z.
2.Sumefekt
AnimpulseSentByaPresynapticneuronandtheammontofTransMitterReleasecausedbyitisgenerallyNoteNexOmaketSynapticMembraneuronsgenerateactionPotencials.Onlywhenaseriesofimpulsesaretransmittedcontinuouslyfromtheterminalofapresynapticneuron,orarowofimpulsesaretransmittedfromtheterminalofmanypresynapticneuronsatthesametime,andthereleasedchemicaltransmittersaccumulatetoacertainamount,canthepost-synapticneuronbestimulatedtoproduceActionpotential.ThisPhenomenoniscalledSummation.InhibitoryPostSynapticPontialScAlsObeSummed.
3.Synaptické zpoždění
NerveimpulsareTransMittedFrompsynapTicterminalStopostsynapticneurons, který mumundundergo: thereeaseofchemicaltransmitters, difúze anativSefEmEmbRanecauseepsp, andonlyafterthesummationcanpost-synapticneurngonEnceptionSonElactionsGenactionPotencials.THECHARACTERISTICOFTISTRASMISSIONTHATKESALONGTIESSYNAPSYNAPTICDELAY.Podle podnětu, thetimeForanimpulSeoPassThroughhasynapseISabout0.3 ～ 0.5ms.
4.Změny
Inareflexactivity, ifatthesametime, theimpulsefrequencesofthedorsafferentrenvereandtheabdominalrooterentRerentRevearereCoredseparedseparedseparedseparedseparedseparedseparedse.BecausetheexcitemenTofthTheefErentNerVenotonlydendSontHetHeafferentImpulse, italsodependsontheFunctionStateofTheefferentNeuroniTefer.Inthepolysynapticreflex, thesituationIsmoreComplicated.PoimpulSeenterTherenterfromTheafferEntnerve, itmustbetransMitedbytheinterneuron.Proto frequencyoftheefferentNeuron'sfiringalsodependSotheFefunctionStateandContactMethodoftheinterneuron.
5.SensitivityTointernalandexternaLelenvironmentChanges
ThesynapsesbetweenNeuronsAremostSusceptibletointernalenvironmentChanges.Hypoxie, riseandfallOfph, změny insionconcentration atd.CanChangetHransmissionCapacityOfSynapses.HypoxiacanmakeneuronSandSynapSeSLoseexcitability, ConductionDurbancesAndevenNenneronaldeath.Inalkalóza, theexcitabilityOnSoronsisAbnormálně zvýšená, aevenconvulsionsionccur; inacidóza, theexcitabilitySDecredated a inseverecass, itcausescomacoma.
6.SensitivityToCiveChemicalSandeasyfatigue
MnohoCentralDrugsaremostlyLocatedSapses.Onerugscanblockorenhancenaphynaptictransmission, taciascaffein, theobromin a theophyllinecanincreasheSesensitivityOfPostSynapticMembraneexcitatoryTransmitters, zejména formysynapsinhebrain.StrychninecanreduCesensitivityofththePostsynapticMembranetoinhibiteRnransmitters, vede kExcessiveneuronalexcitement, asaparticularlyOllyObviouseffectonthespinalcord.ItisclinicallyusesAsSaspinalcordstimulant.Různé receptoragonistyrblockersCandiRectlyActonPostSynapticMembRanereceptorstoexertphysiologicalEftects.
ThesynapseistEmostFatigue-PronelinkintereFlexarc.ThecakuseoffatigueinSynapTicTransmissionMayberatedtothedeptionofTransMitter.TheAppearanceoffatigueisaproTectiveInhibitionToPreventTheCentralNervOUSSystemFromoveRexciting.
Přenosový mechanismus
SynaptiCtransmision: TheProcessofimpulSesetRansmissionFromoneneurontotrotroughroughAsynapsiscalledsynaptiCtransmision.
1.TRANSMISSIONMECHANISMOFCHEMICKYNAPSSES
WhenthenerveimpulseistransMitedTotheaxonterminal, ThePresynapticMembraneisexcited, a theActionPontientalandonTransferfersfer.ATTHISTIMIME, PERMEABILITYOFTHESynapticMembranetoca2+Zvýšení.Ca2+flowsintothesynaptosomefromthesynapticcleftalongtheconcentrationgradient,andthenthechemicaltransmittercontainedinthevesicleisreleasedintheformofquantumrelease,reachingthesynapseTouchthegap.AfterthechemicalTransMitterIsReased, itDiffuseStothePostSynapticMembreththesynapticcleft, a BindstothespecialreceptoreposteriorMembran, změna, která má být výhrada..ThisChangeinthepontientialofTheposteriomMbraneIscalledPostSynapticPotenty.DuetothedifferenceInTransMiterstheireffectSopereabilityOfPostSynapticMembrany, thereretWotypeSofPostSpostSynapticPotencials, jmeelyexcitatoryPostSynapticPontienTanInhinihilihinihilihinihilihinihilihinihilihinihilihinihibitesPotentAnces.
①excitatoryPostSynapticPotencial (EPSP)
Whentheactionpotentialistransmittedtotheaxonterminal,itexcitesthepresynapticmembraneandreleasesexcitatorychemicaltransmitters(excitatorytransmitter),thetransmitterdiffusestothepostsynapticmembranethroughthesynapticcleftandbindstothereceptorsoftheposteriormembranetoincreasethepermeabilityoftheposteriormembranetoNa+,K+,Cl-,especiallytoNa+,andNa+inflows.LocaldepolarizationofThePosteriOrMembraneoccurs.ThisLocalPontientialChangeIscAllededexcitatoryPostSynapticPotental (EPSP).ItcanbespreadinTheforMofelectRicTsion acanbeSummed.Ifmultipleactionpotentialsaretransmittedcontinuouslyfromthesamepresynapticterminal,orarowofactionpotentialsaretransmittedfrommultiplepresynapticterminalsatthesametime,theexcitatorypostsynapticpotentialscanbesuperimposedtoincreasethepotentialamplitude.Atthethresholdpotential,thatis,whenthemembranepotentialisdepolarizedfrom-70mVtoabout-52mV,itwillcausetheinitialsegmentoftheaxonofthepost-synapticneurontofirstbursttheactionpotential,generateaspreadingactionpotential,andconductitalongtheaxon,Spreadtotheentirepost-synapticneuron,showingtheexcitementofthepost-synapticneuron.Tento projektscallededexcitatorySynaptiCtransmission.
②InhibitoryPostSynapticPoTENTY (IPSP)
Ať už se inhibitoninterneuronsAreexcited, jejich TerminalsReleaseInhibitoryTransmitters.TrytransMitterDiffuseStotherearMemBraneandbindstothereceptorhertherearMembran, který sekvíraliabilityOftherearmembranetok+, obzvláštětocl----.ZvýšenápolarizaceMeanshyperpolarizace.ThisHyperpolarizationPentialSIsCallEdInhibilityPostSynapticPotentAnt (IPSP) a ThisProcessisCallEdinhibitorySynaptiCtransmision.
2.TEMECHANISCOMISCOFELECTICKYNAPTICTRANSMISSION
TransmisionfelectricalSyNapsEsisStHroughTheactionofelectricity.To, WhentheactionPontientofThEnynapticneuronreachestheNerveterminal, theactionPontinentOfThepostsynapticComponentisCausedbyTheactionFthelocalcurrent.WHentheimpulSedosNotreachTheranypynaptinal, ithasananodicelectrotoniceffecToNthynapticMembran, který sekresulESeMeMbranepontientofThePostSynapticMembranneandeucesitsexcitability.WhenteactionPontientistrantsMitedTothepresynapticterminal, therevereterminalisnegative, julikeacathode, který jectsasacathodicelectrasion, který redukulovalEMBranepontientofthePostsynapticMembraneandincreaseSeestheestheexcitability.WhentheexCitabilityInSisedSoacernlevel, areveimpulseisgeneratedAndspreadswithalocAlelectriccurrent.
Funkce: PromototheFefunctionFifferentNeuronstonstoproducesynchronizovaní firiring.
Přenosová dividence
Synaptický přenos
To senoprotoplasmicConnectionbetweenningony.TheConnectionbetweenthemonlydedsonContactWitheachtherother, to je, že se skrí podaří oniminalmakescontactwithotheronsAnsAndtransMitSexcitementorinhibitionhibitionhition.TheSontactsitesArecalledSynapses.
1.KlasifikaceOfSynapses
①ClassificationOfSynapticContactSites
CanBedIDidedInto: (1) Axo-Dendriticynapses (axo-DendriticyNapse) ”ReferstotheContactBeentheaxONENDOFANERONANDTHEDDRITEDRITEDRITEDRITESOFTHENDRITESOFTHENTON.(2) Axo-SomaticSynapse (axo-somaticsapsypse) RefstotheContactBeentheaxOnterminofaneundandtheCellbodyofTheNexNeuronon.(3) Axaxonicsynapse (axo-axonicsynapse) „RefstotheContactBeentheaxendofoneneronandtheaxon (startoensegmentofaxon) OraxonendOfTheNexNeuron.
Kromě toho v centrálním systému, strom, těla, těla, tělesné stromy, body-bodyandothershynaptické spojení.InRecentyears, ithasalobeendiscovered thetanaxis-treeortree-treetepeauapsapse (autoapnaps) může být vytvořenbetweentheprotrusionsOfthesaneurononononus.②ClassificationCordingTothewaySynapSStransmitinformace
CanBedIDidedIndochemicalSynapsesAndelectricalSynapses.ChemicalSynapSesrelyonpre-synapticneuronterminalStoreLeasSespecialChemicalSubSmediaSortransmitingInFormationToaftectPost-synapticneurons.ElectricyNapSesrelyOnTheBioelectricityAndionExchangeofpre-synapticneuronstorectlytransmitinformationtoaftectPost-synapticneurons.
③ccordingTotheFefunctionClassificationOfSynapses
CanBedIDidedIntoexcitatorySynapse (excitatorySynapse) a inhibitorysynapse (inhibitorysynapse).TheinformationTransmisionoftheSynapseseDePolarizeSpostSynapticMembraneandgeneratesexcitatoryPostSynapticPontialScallededexcitatorySynapses.TheinformationTransmisionoftheSynapsecausestHepostsynapticMembranetoHyperpolarizeandgeraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateraterateRibitopostsynapticPontialScalledinhibilitorySynapses.
2.BasicStructureofSynapse
①chemicalsynapse
TheaxOnterminofaneuronfirstdividesInSomanysMallbranches, TheendofeachsMallBranchexpandsintoasphericalshape, nazývaný Ssynaptosome.TheCorpuscleformsAsynapticConnectionswiththeCellbodyOrDendRiteSothernernerve.Undertheelectronmicroscope, itwasObSersedtHecellMemBranesofthetwoneuronSattheSynapseDeDedNotFuse.V tom jeagapbetweenthetwoneurons, které jsou uvedeny 200-500, nazývá se.TheemBranetthatforthesynapticcleftbythesynaptosomesiscalledThepresynapticMembran a TheoterMemBranetthattHesynapticcleftiscalledThePostsynapticMembrane.Proto asynapseiscomposeoseofTreeParts: ThePresynapticmembrane, ThesynapticcleftandTostSynapticMembran.SynapticvesiclesContainMoreMitochondriaAndalarGenUmbempvesicles, které jsou vyhlášeny.TheveSiclesContainexcitatoryOrinhibilitionTransmitters.MitochondriacontainenzymestHatsynthesizeTransmitters.Tím se vyskytují.
②ElectricalSynapse
ThestructuRuralBasisofelectricalSynapseIsgapjunction, která jethepLacewheretWoneuronMembranesareincloseContact a athegapBeenthetWoMembranesonly20-30.THERERENOSynapticvesiclesrNerotransMittersintheaxonendsOnsOnsOfpresynapticneurons.ThereereChannelsmComMunicateTeCtytoplasMoftHetwocellsattheConnectionsite.NabitycanntransMitelectricalSignalshroughTheSechannels.ThissignaltransmisionSgenerallybidirections.Proto, TheinformationTransmissionConlectedTotheCollection artingPartSoftheMedicalEducationNetworkIndofelectricalTransmision, který je kompenzováno, že jezdí z nich.FunctionofelectricalSynapSesMayBetopromotesynchronousDischargeofdifferentNeurons.ThespeedofelectricaltransmisionsmisFast a thereisalenoicubationPeriod.ElectricSynapsCanexistBetweenDendritesandDendrites, CellBodiesAndCellbodies, AxonsandCellbodies, AxonsAndDendrites.
Nesynaptický přenos
INADDITIONTOSynapticchemicalTransmission, ThisSalson-SynapticchemicalTransmision.TheresearchinthisareaWasFirstCarriedOtounThesympaticGanglionadRenergicneurons.ExperimentShaveObsersedtThatTheaxendsOnsOnGrenergicneuronshavemanybranches, andtherearealargemumbemumberOfnodularvaricosebodieSonthebranches.TheVaricoSosebodyContainSalarGenUmberofsMallvesicles, které se vyskytují.Nicméně, ThevaricoSedyDoesNotformasynynapticConnectionswiththeeffectorCells, butislocatedNeartheeeffectorfectorctorsction.WhenthenerveimpulsereachestHevaricoSosebody, thetransmitterIsReadesedFromThevaricoSebody, andreachesthereceptorscollectedSortedbytheeffectorcellmeDeducationNetWorchDifFusion, sothattheeffectorcellreactreActRectreActRectreACtststststststreActreActreActreActreActreActReACtreActreActreActreActReActreActreActreActreActreActreActR.SinnethischemicalTransmisionSNotCarriedOutThroughSynapses, itiscallednon-synapticchemicaltransmision.IntheCentralNerVoussystem, thereeKnownTransmissionMethods.Forexample, thereareunmyelinované firmy sveryveryfineMiaMiSinthereBralCortex, který ORenoradrenergicfibers.TheremanyvaricosebodieSonthefiberbranchesthatcanbered.Norepinephrin, mestofThisvaricosebodyDotformSynapSesWithinnervatedNeurons, sothetransmissionsanon-synapticchemicaltransmissionsmEthothothotless.Kromě toho, serotonergní fibersinthecenterCanasCarryout on-SynapticchemicalTransmission.
Ve srovnání snipticchemicaltransmission, nesynapticchemicaltransmissionhastheFollingCaracteristics: ①ThereisNospecialStructureofPrynapCyMEMBRANEANDPostSynapticMembrane.② THEESNOONE-TOEDOMINANCELATIONSHIP, TOS, ONEVARICOSESODECANDOMEMOMEFEEFTORCECTELLS.③thedistancebetweenthevaricosebodyAndtheeffectorCellISatleast200?.④ThediffiseDistanceofTransMitterIslarge, sothetimeittakestotransmitcanbelongerthan1s.⑤WhenThetRansMitterDiffuseStotheefEftorctorCell, ať už jde o přenos.
Funkce: V nichž se bez ohledu na to; TheDistanceBetweenthevaricoSosebodyAndtEtAltEllisrelativněLong;.