Domov Technika Centrální nervový systém

Centrální nervový systém



Introduction

Thecentralnervoussystem(CNS)isthemainpartofthenervoussystem,includingthespinalcordinthespinalcanalandthebraininthecranialcavity;itslocationisofteninanimalsThecentralaxisofthebodyiscomposedofobviousbrainganglia,nervecords,orbrainandspinalcord,andtheconnectionsbetweenthem.Inthecentralnervoussystem,alargenumberofnervecellsgathertogethertoformanetworkorcircuitorganically;itsmainfunctionistotransmit,storeandprocessinformation,producevariousmentalactivities,anddominateandcontrolallanimalbehaviors.

Composition

Thecentralnervoussystemofvertebrates:thevertebratebrainislocatedinthecranialcavity,andthespinalcordislocatedinthespinalcanal.Thecentralnervoussystemofvertebratesdevelopsfromtheneuraltubeonthedorsalsideofthebodyatembryonictime.Theheadendoftheneuraltubeevolvedintothebrain,andthetailendbecamethespinalcord.Theneuraltubecavitydevelopsintotheventricleinthebrainandthecentraltubeinthespinalcord.Thebrainisthreebrainsatthebeginning:forebrain,midbrain,andrhombohedralvesicles,andlaterevolvedintoteleencephalon,diencephalon,midbrain,cerebellum,ponsandmedullaoblongata.

Manynervefibersinthecentralnervoussystemofvertebratesaremyelinated.Whentheyaregatheredtogether,theylookwhitetothenakedeyeandarecalledwhitematter.Onthecontrary,thepartwherethenervecellbodiesareconcentratedisgraytothenakedeyeandconsistsofalargenumberofnervecellbodiesandalargenumberofsynapsesondendrites,calledgraymatter.Thecentralnervoussystemiscomposedofacollectionofnervecellbodieswiththesamefunction,andthegraymattermasseswithaclearrangearecallednervenuclei.Theneuralactivitiescarriedoutinthespinalcordaremainlyreflexiveactivitiescarriedoutbysegments;however,manyactivitiesofvertebratesareintegrated,whichdependsontheconnectionbetweenthebrainandthespinalcord.Therearemanynervefiberbundlesrunninglongitudinallyinthecentralnervoussystem.Therearealsomanycommissuralfibersbetweentheleftandrightsidesofthebrainandspinalcord,thethickestofwhichisthecorpuscallosumbetweenthetwohemispheresofthebrain.

Features

Thespinalcordstillretainstheoriginalneuraltubepattern,withgraymattersurroundingthecentraltubeandwhitemattersurroundingthesurfaceofthegraymatter.Thedorsalpartofthespinalcordisdevelopedfromthewingplateoftheneuraltubeduringtheembryonicperiod,andmainlyreceivesincominginformationfromthereceptors.Theventralpartisdevelopedfromthebaseplate,anditsfunctionismotility.Thepositionofthecranialnervenucleusofthebrainstemisbasicallysimilartothearrangementofthespinalcordaccordingtoitssensoryandmotorproperties.However,duetothechangesintheshapeoftheventricle,itisnotasobviousandneatasthespinalcord.Somenervenucleiinthebrainstemthatareneithersensorynormotor,suchasrednucleiandolivenuclei,arelocatedindifferentpartsofthebrainstem.Duetotheappearanceoftheventricleandnumerousnervebundlesandconductionbundles,thestructureofthebrainstemismuchmorecomplicatedthanthatofthespinalcord(seetable).Thegraymatterofthecerebrumandcerebellumaremainlydistributedinthesurfacelayer,calledthecerebralcortexandcerebellarcortex,respectively;whilethewhitematterisinthedeeplayer.

Struktura

Míša

Máteřní kord-nízkoúrovňová část centrálního nervového systému, umístěná v míšním kanálu, na předním konci foramenmagnumaMozek je spojen s periferními nervy.

Spinalcordmembrane:Thespinalcordiscoveredwiththreelayersofconnectivetissuemembranes,calledthespinalmembrane,whicharespinalpiamater,spinalarachnoidmembrane,andspinalduramaterfromtheinsidetotheoutside.Thespinalarachnoidandsoftmembraneformaconsiderablespacecalledspinalsubarachnoidspace,whichisfilledwithcerebrospinalfluid.Anarrowsubduralspaceisformedbetweenthespinalduramaterandthearachnoid,filledwithlymph.

Tvar: Tvar je lehce zploštělý nahoru a dolů, pak se nazývá dřeňový kužel a má dvě zvětšené části zvané cervikální zvětšení a bederní zvětšení (pánevní nerv, ocasní nerv). Spolu s dřeňovým kuželem a koncovými vlákny tvoří sachor);

Viewedfromthecrosssection,thecenterisabutterfly-shapedgraymatter,andthesurroundingiscomposedofwhitematter.Thereisacentraltubeinthecenterofthegraymatter.Thepartofgraymatterprotrudingbackwardandoutwardistheposteriorhorn,whichisconnectedtotheposteriorrootofthespinalnerveandcontainsinterneurons;thepartprotrudingforwardistheanteriorhorn,whichcontainsmotorneurons,anditsfibersconstitutetheanteriorrootofthespinalnerve;thelateralhorncontainsVegetativeneuron.Whitematteriscomposedofnervefibers,whichcanbedividedintoanteriorcord,lateralcord,andposteriorcordaccordingtolocation,whichconnectthebrain,spinalcord,andvarioussegmentsofthespinalcordrespectively.

Funkce míchy má následující dva aspekty:

First,theconductionfunction,thedeepandsuperficialsensationsofthewholebody(exceptthehead)andmostThesensationoftheinternalorgansmustbetransmittedtothebrainthroughthewhitematterofthespinalcordtoproducesensation.Thebrain'sregulationofthemovementofthetrunk,thestriatedmusclesofthelimbs,andtheinnervationandregulationofsomeinternalorganscanalsobeachievedthroughtheconductionofthewhitematterofthespinalcord.Ifthespinalcordisinjured,itsuploadingandsendingfunctionswillbeimpaired,causingsensoryimpairmentandparalysis.

Second,reflexfunction,therearemanylow-levelreflexcentersinthegraymatterofthespinalcord,whichcancompletesomebasicreflexactivities;suchasmusclestretchreflexcenters,urinationanddefecationcenters,andlow-levelreflexcentersforsexualactivities,Plantarreflex,kneejumpreflexandvisceralreflexandotherbodyreflexes.

Undernormalcircumstances,thereflexactivitiesofthespinalcordarecarriedoutunderthecontroloftheadvancedcentralnervoussystem.Whenthespinalcordissuddenlytraversedandlosescontactwiththehigh-levelcenter,atemporaryspinalshockwilloccur.Spinalcordinjurycaninterruptacertainlevelofphysiologicalfunction.Duetoadvancesinmedicine,manypatientswithspinalcordinjuryhavebeenabletorecovertheirphysiologicalfunctions.

Brain

Thehumanbrainisaspongynervetissueweighingabout1,400gramscomposedofabout14billionbraincells.Thebrainisthemainpartofthecentralnervoussystem.Intermsofstructure,itisdividedintothreeparts:forebrain,midbrainandhindbrainaccordingtodifferentparts,eachwithdifferentfunctions.

1.Zadní mozek je umístěn ve spodní části mozku, která zahrnuje tři části:

⑴Theoblongata,locatedattheupperendofthespinalcord,isconnectedtothespinalcordandhasathintubeshape,aslargeasafinger.Themainfunctionoftheoblongataistocontrolbreathing,heartbeat,swallowinganddigestion.Aslightinjurycanbelife-threatening.

⑵Thepons,locatedabovethedilatation,isatubularbodycomposedofnervefibersthatislargerthanthedilatation.Theponsconnectstheprolongedbrainandthemidbrain,andifdamaged,itmaycausesleepdisorders.

(3)Thecerebellum,locatedbehindthepons,resemblestwoconnectedwrinkledhemispheres,anditsfunctionismainlytocontrolthebody'smovementandbalance.Ifthecerebellumisdamaged,itlosestheabilityofthebodytomovefreely.

2.Themidbrainislocatedabovethepons,justinthemiddleofthewholebrain.Themidbrainisthereflexcenterofvisionandhearing.Inthecenterofthemidbrain,thereisanetworkofnervetissuecalledthereticularstructure.Themainfunctionofthemeshstructureistocontrolthestateofconsciousnesssuchasawakening,attention,andsleep.Theroleofthereticularstructureextendstothepons,midbrainandforebrain.Themidbrainandhindbrainponsandoblongataarecombinedtogether,calledthebrainstem,whichisthecenteroflife.

3.Theforebrainisthemostcomplexandimportantpartofthebrain.Theforebrainmainlyincludesfiveparts:

⑴Cerebralcortex,themostimportantpartofthecentralnervoussystem,withanaveragethicknessof2.5to3.0mm,anareaof​​about2200squarecentimeters,coveredwithConcavegrooveandconvexback.Thedeepgroovethatseparatestheleftandrighthemispheresbecomesalongitudinalfissure.

Thebottomofthelongitudinalfissureisconnectedbythecorpuscallosum.Onthelateralsurfaceofthecerebralhemisphere,thesulcusperpendiculartothelongitudinalfissurefromthetopiscalledthecentralsulcus.Ontheoutersideofthehemisphere,thegroovethatrunsdiagonallyfromthefronttothebacktothetopiscalledthesylvianfissure.Theposteriorpartofthemedialhemispherehasparietooccipitalcleft.Beforethecentralgrooveisthefrontallobe.Theparietallobeisbehindthecentralgroove,infrontoftheparieto-occipitalfissure,andabovethelateralfissure.Belowthesylvianfissureisthetemporallobe.Theoccipitallobeisbehindthelateralfissure.Therearemarginalleavesaroundthecorpuscallosum.Eachleafcontainsmanytimes.Thereisacentralanteriorgyrusinfrontofthecentralsulcusandacentralposteriorgyrusbehind.Thedeeppartofthecerebralhemisphereisthebasalganglia,whichmainlyincludesthecaudatenucleusandthelenticularnucleus,collectivelycalledthestriatum.Itsfunctionismainlytoregulatemuscletensiontocoordinatemovement.

⑵Thelimbicsystem,thelimbicsystemisacomplexnervoussystemthatislocatedunderthecorpuscallosumandincludesavarietyofnervetissues.Thestructureandfunctionofthelimbicsystemarestilluncertain.Inadditiontopartofthethalamusandhypothalamus,italsoincludesthehippocampusandamygdala.Thefunctionofthehippocampusisrelatedtolearningandmemory,andthefunctionoftheamygdalaisrelatedtomotivationandemotion.

(3)Thethalamusisanegg-shapednervetissue,whichislocatedbelowthecorpuscallosumandfunctionsasatransferstation.Nerveimpulsesfromthespinalcordarefirststoppedinthethalamus,andthentransmittedfromthethalamustotherelevantareasofthecerebralcortex.Ifthethalamusisdamaged,itwilldistortthesensesandmakeitimpossibletocorrectlyunderstandtheworldaroundthem.

⑷Thehypothalamusislocatedbelowthethalamus.Althoughitsvolumeissmallerthanthatofthethalamus,itsfunctionismorecomplicatedthanthatofthethalamus.Thehypothalamusisthemaincontrolcenteroftheautonomicnervoussystem.Itisdirectlyconnectedtothevariousareasofthecerebralcortexandtothepituitaryglandwhichcontrolstheendocrinesystem.Themainfunctionofthehypothalamusistocontroltheendocrinesystem,maintainmetabolism,regulatebodytemperature,andisrelatedtohunger,thirst,sexandotherphysiologicalmotivationsandemotions.Damagetothehypothalamuswillaffecttheindividual'seatinghabitsandexcretoryfunction.

⑸Thepituitaryglandislocatedunderthehypothalamusandisaslargeasapea.Althoughitbelongstotheforebrainintermsoflocation,itisoneofthemostimportantsecretoryglandsintheendocrinesysteminfunction.Inaddition,thecorpuscallosumconnectsthetwohemispheresofthebrain,allowingtheneuralnetworksofthetwohemispherestocommunicatewitheachother.

Thebrainisthehigh-levelpartofthecentralnervoussystem.Itislocatedinthecranialcavityandcontinueswiththespinalcordattheforamenmagnum.Thebraincanbedividedintofourparts,brainstem,diencephalon,cerebrumandcerebellum.

(1)Mozkový kmen,který se odzadu dopředu dělí na podlouhlý dýně, hřebíky a střední mozek.

Themedullaoblongata:Itistheendofthebrainstem,whichiswideinthefrontandnarrowintheback.Thereareconesandtrapezoidsontheventralsideofthemedullaoblongata.Thebacksideisdividedintoaclosedpartandanopenpart.

Pons:Locatedinthefrontofthemedullaoblongata,itcanbedividedintothebasepartandthecover.Thebasepartbulgeslaterally,andthetrigeminalnervepenetratesatbothends.

Midbrain:Locatedbetweentheponsandthediencephalon,thereisatubecalledthemidbrainaqueduct.Thebackendcommunicateswiththefourthventricle,andthefrontcommunicateswiththethirdventricle.Dividedintodorsalquadruplebody(topcover)andventralbrainfeet.

Rednucleus:Itisapairoflargeoval-shapedgraymatternuclei,whichcanbeseeninthecrosssectionoftheanteriorcolliculusinthefrontofthefootofthebrain.Itisanimportantconversionstationonthedownwardmovementtransmissionpath.

(2)Diencephalon,anterolaterallyconnectedtothebasalnucleusofthebrain,insideisthethirdventricle,whichsurroundsinaring,andismainlydividedintothethalamusandthehypothalamus.

Thalamus:Zabírá většinu thalamu.Jedná se o pár oválných hmot šedé hmoty.3komory.

Hypothalamus:alsoknownasthehypothalamus,locatedbelowthethalamus,isthesubcorticalcenteroftheautonomicnervoussystem.Viewedfromtheundersideofthebrain,theopticnervesonbothsidesformtheopticchiasm,grayNodules(funnel),nipplebody.

(3)Mozek:

Cerebralneocortex:distributedonthebackandfront,lateralandposteriorsides,itcanbedividedintothefrontallobeandtheoccipitallobe(visualArea),thetemporallobeonthelateralside(auditoryarea),andtheparietallobeonthedorsalside(generalsensoryarea).BasalgangliaTherearesomelargegraymatterclustersinthewhitematterinsidethebrain,calledthebasalgangliaorbasalnucleus.Theyarethesubcorticalmotorcenterandaremainlycomposedofthecaudatenucleusandthelenticularnucleus.

Čuchový mozek: tvoří spodní stranu terminálního mozku, včetně čichové žárovky, čichového gyrusu, čichového trojúhelníku, piriformního laloku, hipokampalgyru, hipokampu a zubatého gyru.

Marginallobe:referstotheoppositecortexbetweenthetwohemispheresofthecerebralhemisphere,includingthecingulategyrus,corpuscallosum,etc.,whichperformthefunctionsofregulatinginternalorgansandreproductiveactivities.

Whitematter:Thewhitematterofthecerebralhemispherecontainsthefollowingthree-sacredfibers:commissuralfibers—connectingthecorticalfibersoftheleftandrightcerebralhemispherestoformthecorpuscallosum;connectingfibers—connectingthefibersbetweenthegyrusandlobesoftheipsilateralhemisphere.Projectionfiber-connectingtheupanddownfibersbetweenthecerebralcortexandotherpartsofthecenter.

Lateralventricle:Locatedinsidethecerebralhemisphere,thereisoneoneachside,calledthefirstandsecondventriclesrespectively,andcommunicateswiththethirdventriclethroughtheinterventricularforamen.

(4) Mozeček:

Thecerebellumisslightlyspherical,locatedonthedorsalsideofthemedullaoblongataandpons.Therearetwoshallowgroovesonthedorsalsidethatdividethecerebellumintothreeparts:thecerebellarhemisphereandthevermisDepartment.

(5)Oběh mozkových blan, komorového systému a mozkomíšního moku:

Minges:Similartothespinalcord,therearethreelayersofmeningesontheoutsideofthebrain,fromtheinsidetotheoutsidearethesoftbrains.Membrane,cerebralarachnoidandduramaterformthesubarachnoidspaceandsubduralspacerespectively,butthereisnoepiduralspace.

Ventricularsystem:lateralventricles,thethirdventricleinthediencephalon,themidbrainaqueductinthemidbrain,thefourthventricleinthecerebellum,theponsandthemedulla,andthecentralcanalinthespinalcord.,Filledwithcerebrospinalfluid,togetherconstitutetheventricularsystem.

Cerebrospinalfluid:Itisaspecialfluidthatisproducedbythechoroidplexusofthelateralventricle,thethirdventricleandthefourthventricle.Itfillstheventricularsystemandthesubarachnoidspaceofthecerebrospinalcordinthelongitudinalfissureofthebrain.Flowintotheveintocompletethecirculationofcerebrospinalfluid.

Role

Thecentralnervoussystemisagroupofneuronsthatregulateaspecificphysiologicalfunction.Suchasrespiratorycenter,bodytemperatureregulationcenter,languagecenterandsoon.Usually,somesimplereflexcentersarenarrow,suchasthecenterofkneejumpreflexinthelumbarspinalcord,andthecenterofcornealreflexinthepons.However,thecenterthatregulatesacertaincomplexlifeactivityhasawiderange.Forexample,thecenterthatregulatesbreathingmovementisscatteredinthemedullaoblongata,pons,hypothalamus,andcerebralcortex.Themedullaoblongatarespiratorycenterisbasic,andtherestofthecentersatalllevelsaffectit.Themedullaryrespiratorycenterregulatesrespiratorymovement.Itcanbeseenthatthereflexcenterisnotjustalimitedisolatedareainthecentralnervoussystem.Evenifthereareintricateconnectionsbetweenneuronsinacertainnervecenteratthesamelevel,theyaffecteachotheranddeterminethefunctionalactivitystateofthiscenter.Theactivityofthenervecentercandirectlyactontheeffectorthroughthenervefiber,orindirectlyactontheeffectorthroughthehumoralpathway.Thishumoralpathwayreferstoendocrineregulation.Sincethenervecenterofvariousreflexeshasadefinitelocation,checkingtheperformanceofacertainreflexordirectlyobservingtheactivityofcertaineffectororganscaninferthechangesinthefunctionofthecentertodiagnosediseasesordeterminethecondition.Ifthecenterofthecornealreflexisinthepons,lightlytouchtheedgeofthecorneawithcottonwool.Thenormalresponseistoclosetheeyes.Ifthecornealreflexisdullordisappear,itmeanstheponsisinjuredorcoma;TheAchillestendonshouldnormallybeflexedtotheplantarsurface.IftheAchillestendonreflexisweakenedordisappeared,itindicatesthecorrespondingcentralinjury.

Thecentralnervoussystemislikeahugecontainerofinformationprocessor,theresultofprocessingcanappearreflexactivities,feelingormemory.Forexample,whenananimalencounterssomethingharmful,itwillevade,whichisareflexaction.Inthisreflexaction,theinformationcausedbythenoxiousstimulusistransmittedtothecenter,processedbythecenter,andthentransmittedthroughthemotornerves,causingmuscleactivity.Afterthecentralnervoussystemreceivesincominginformation,itcanbetransmittedtospecificpartsofthebraintoproducesensations.Thiscanbeclearlyreportedinhumansbasedonsubjectiveexperience.Animalsmayalsohavethesameorsimilar"feeling".Aftersomesensoryinformationisintroducedintothecentralnervoussystem,afterthelearningprocess,itcanalsoleavetracesinthecentralnervoussystemandbecomenewmemories.

Whenthecentralnervoussystemcompletestheabove-mentionedfunctionalactivities,ithasaveryimportantfeature,thatis,coordinationandintegration.Coordinationreferstotheprocessinwhichthevariousfunctionsoftheoverallfunctionarecombinedintoaharmoniousmovement.Integrationreferstotheprocessofturningasingle,partialactivityintoacompleteactivity.Here,theoutputisnolongerinaone-to-onerelationshipwiththeinput,itcanbemultipleinputs,transformedintoasingleoutput,orviceversa.Forexample,whentheleftlegisflexed,therightlegisgenerallystraightenedinordertosupporttheweight,whiletheleftlegflexormusclesarecontracted,buttheextensormusclesarerelaxed.Theseactivitiesallreflectthecoordinationandintegrationofthecentralnervoussystem.

Původ

Retikulární nervový systém pochází z neuroektodermu, který se liší od neurální trubice a neurálního hřebene.

Vývoj tkáně

1. Neurální trubice: Na začátku třetího týdne lidského embrya, notochordinuje ektoderm střední čáry zad, neuroektoderm tvoří neurální trubici a přední část nervové trubice, např. vstoupí do míchy.

2.Neuralcrest:Duringtheformationoftheneuraltube,someneuroectodermalcellsattheedgeoftheneuralfoldsinkwiththeformationoftheneuraltube,formingtwocellcordsontheoutsideoftheneuraltube,calledtheneuralcrest,Theneuralcrestdifferentiatesintoganglia,glialcellsandadrenalmedullachromaffincellsoftheperipheralnervoussystem.

3.Neuraltubeepithelialdevelopment:Theearlyneuralplateisasinglelayerofcolumnarepithelium,calledneuroepithelium.Whentheneuraltubeisformed,thetubewallbecomespseudostratifiedcolumnarepithelium.

⑴Earlystructure:innerlimitingmembrane:alayerofmembraneontheinnersurfaceoftheneuraltubelumen;neuroepithelialcells:pseudostratifiedcolumnarepithelialcells;outermembrane:thebasementmembraneoftheepithelium.

⑵Structuraldevelopment:Theoriginalneuroepithelialcellsoftheinnerlimitingmembraneceasetodifferentiateandbecomealayerofcuboidalorshortcolumnarcells,calledtheependymallayer.Mantlelayer:Neuroepithelialcellscontinuetodivideandproliferate,andsomecellsmigratetotheperipheryofneuroepithelialcellstobecomeneuroblasts.Afterthat,neuroepithelialcellsdifferentiateintoglialcellsandmigratetotheperipheryofneuroepithelialcells.Thus,anewcelllayerisformedbyneuroblastsandglialcellsontheperipheryoftheoriginalneuroepithelialcells,whichiscalledthemantlelayer.Marginallayer:Theneuroblastsofthemantlelayeraresphericalatfirst,andquicklygrowprotrusions.Theprotrusionsgraduallygrowandextendtotheouterperipheryofthemantlelayer,forminganewstructurecalledthemarginallayer.Withthedifferentiationofneuroblasts,theglialcellsinthemantlelayeralsodifferentiateintoastrocytesandoligodendrocytes,andsomecellsenterthemarginallayer.

4.Nervecellsdevelopintoneuronalcells,whicharepost-dividingcells,andgenerallynolongerdivideandproliferate.Atfirstitwasround,calledanon-polarneuroblast.Later,twoprotrusionsoccurredandbecamebipolarneuroblasts.Theprotrusionsonthesideofthebipolarneuroblastsfacingtheneuraltubecavitydegenerateanddisappear,becomingunipolarneuroblasts,extendingtotheedgeOneprotrusionofthelayergrowsrapidlytoformaprimitiveaxon,andanumberofshortprotrusionsareformedonthemedialendoftheunipolarneuroblast,whichbecomesprimitivedendrites,andthenbecomesamultipolarneuroblast,andeachpolarneuroblastfurthergrowsanddifferentiatesintoeachpolarnervecell.

5.Glialcelldevelopment.Glialcellsoccurlaterthannervecells.Glioblastsfirstdifferentiateintoprecursorcellsofvarioustypesofglialcells,namelyastrocytesandoligoblasts.Dendrocytes;astrocytesdifferentiateintoprotoplasmicandfibrousastrocytes;oligodendrocytesdifferentiateintooligodendrocytes;glialcellsalwaysmaintaintheabilitytodivideandproliferate.

Theoccurrenceofspinalcord

1.Histogenesis:thelowersegmentoftheneuraltubedifferentiatesintothespinalcord.Thespinalcordbasicallymaintainstheabove-mentionedfive-layerstructure:theinnerlimitingmembraneandtheependymallayerbecometheependymaThemantlelayerdifferentiatesintospinalcordgraymatter,themarginallayerdifferentiatesintowhitematterandoutermembrane,anditslumenevolvesintothecentralcanalofthespinalcord.

2.Thejacketlayerevolvesintotwoventralbacksidesoftheleftandrightbaseplates,thetopandbottomwallsoftheleftandrightwingsarethetopandbottomwallsofthetopandbottomsulcus,anteriormedianfissure,andposteriormedianseptum.

⑴Thetwosidewallsoftheneuraltubethickenedrapidlyduetotheproliferationofneuroblastsandglialcellsinthemantle,formingtheleftandrightbaseplatesontheventralpart.Thedorsalpartoftheanteriorhornofspinalcordgrayformstwoleftandrightwingplates,whichformtheposteriorhornofspinalgraymatter.Severalneuroblastsgatherbetweenthebaseplateandthewingplatetoformthelateralhornofspinalgraymatter.

⑵Thetopandbottomwallsoftheneuraltubearethinandnarrow,formingthetopandbottomplates,respectively.

(3)Duetothethickeningofthebaseplateandwingplate,therearetwolongitudinalgroovesontheinnersurfaceoftheneuraltube,calledboundarygrooves.

⑷Asthenumberofcellscontinuestoincrease,alongitudinalgrooveappearsbetweentheleftandrightsubstrates,whichiscalledanteriormedianfissure.Theleftandrightwingplatesenlargeandmovetowardtheinsideandhealatthemidline.Aseptumisformedatthehealingplace,calledtheposteriormedianseptum.

3.Spinalcorddevelopmentbeforethethirdmonthofembryo:thespinalcordisaslongasthespine,anditslowerendcanreachthecoccyxofthespine.Afterthethirdmonth:becausethespinegrowsfasterthanthespinalcord,thespinegraduallysurpassesthespinalcordtothetailTheendisextended,andthepositionofthespinalcordmovesrelativelyupward.Beforebirth:Thelowerendofthespinalcordisflushwiththethirdlumbarvertebrae,andonlytheterminalfilaments(whicharestretchedintoathreadofthespinalcord)areconnectedtothetailbone.Sincethespinalnervesdistributedinsegmentsareformedintheearlyembryonicstageandpassthroughtheintervertebralforamenofthecorrespondingsegment,whenthepositionofthespinalcordmovesrelativelyupward,thespinalnerverootsbelowthecervicalsegmentofthespinalcordbecomemoreandmoreobliquetothecaudalside,tothewaistThespinalnerverootsofthesacralandcaudalsegmentsdescendverticallyinthespinalcanal,formingacaudaequinatogetherwiththeterminalfilaments.

Výskyt mozku

1.Struktura raného mozku.Ve 4. týdnu embrya vytvořila hlava nervové trubice tři otoky, jmenovitě přední mozkové váčky a střední mozkové váčky zepředu dozadu.

2.Whenthestructureevolvestothe5thweek,theheadendoftheforebrainvesicleexpandstobothsides,formingtwoleftandrightendbrains,whichlaterevolveintothetwohemispheresofthebrainandthetailendoftheforebrainvesicleisformedThemidbrainmidbrainvesicleevolvedintothemidbrainrhombohedralvesiclethatevolvedintothecephalichindbrainandthecaudalendofthebrain,thehindbrainevolvedintotheponsandthecerebellarendofthebrain,andtheinnercavityofthemedullaoblongatabecametheventricleandthemidbrainaqueduct.

3.Thedevelopmentofbrainwallstructure.Theevolutionofthebrainwallissimilartothatofthespinalcord.Duetothethickeningofthemantlelayer,thesidewallisdividedintoadorsalwingplateandaventralbaseplate.

⑴Mostofthesidewallsofthetelencephalonanddiencephalonformwingplates,andmostofthecellsinthebaseplateandthesmalltelecephalusmigratetotheoutersurface,formingasmallgroupofcellsinthecerebralcortex.Theformationofthemarginallayerofthenucleusdifferentiatesintothewhitematterofthebrain.

⑵Themantlecellsinthemidbrain,hindbrainandendbrainaggregateintocellclustersorcellcolumns,formingvariousnervenuclei.Thenervenucleiinthewingplatearemostlythenervesinthesensoryrelaynucleussubstrate.Mostofthecoresaresportscores.

(3)Thecerebellumisdevelopedbythesymmetricalthickeningofthedorsalpartsofthewingsonbothsidesofthehindbrain.

Diseases

Thecentralnervoussystemisaffectedbypathogenicfactors(especiallywhentheorganicdiseaseofthenervoussystemcannotbedetected),andthediseasewithmentalactivitydisorderasthemainmanifestationiscalledMentalillness.Asthesayinggoes,mentalillnessisoftenreferredtoas"neuropathy",butitisactuallyincorrect.However,neuropathyandpsychosiscanoftencoexist.Forexample,sporadicencephalitisoftenhaspsychiatricsymptomsasthefirstsymptom,andpatientswithparalyticdementiacanalsohaveneurologicalsymptomsatanearlystage.Someneurologicaldiseases,suchascerebrovasculardisease,epilepsy,encephalitis,meningitis,etc.arecommonclinically.Chronicdiseasesaccountforthemajorityofneuropathies,andtheyoftenlingeranddonotheal,whichhasagreatimpactontheworkandlifeofpatients,andthedisabilityrateisveryhigh.Neuropathycanbecausedbyavarietyofcauses.Manyneuropathiesareofunknownetiology,andmanyaregeneticdiseases.TheapplicationoftechnologiessuchasbrainCTscanandmagneticresonanceimagingenablesrapidandaccuratediagnosisofmanybrainandspinalcorddiseases.However,becausenervecellsarenoteasytoregenerateafterinjury,therearestillnoeffectivetreatmentsformanyneuropathies.

Poisoning

Includingmetalpoisoning,suchasleadpoisoningcancauseperipheralmotornervepalsy,lead-toxicencephalopathy,mercury,arsenic,andthalliumpoisoningalsoaffectthenervoussystem;organicpoisoning,suchasalcoholPoisoningandbarbituratepoisoningcaninhibitthecentralnervoussystem,organophosphatepoisoningcancauseexcessiveexcitementofcholinergicnerves;bacterialtoxinpoisoning,suchasbotulismpoisoningcancausecranialnerveparalysisandlimbweakness,anddiphtheriatoxincancausenerveparalysisandtetanusToxinscancausetonicspasmsofskeletalmusclesthroughoutthebody;animalpoisons(toxinscontainedincoelenterates,shellfish,venomousmosquitoes,spiders,pufferfish,etc.)canalsocauseneurologicalsymptoms(muscleweakness,paralysis,convulsions,ataxia,etc.).

Viralinfections

Includingbacterialinfections,suchaspurulentmeningitisandbrainabscess,causedbyvariouspyogenicbacteria;viralinfections,suchasepidemicscausedbyJapaneseencephalitisvirusJapaneseencephalitis,epidemicchestpaincausedbyBMutantstrains;parasiticinfections,suchascerebralmalaria,cerebralparagonimiasis,cerebralcysticercosis;fungalinfections,suchasCandidaalbicansandcryptococcalmeningitis;Leptospiracanalsocausemeningitisencephalitis.Partofthecauseofepilepsyistheformationoflocalscarsaftermeningealorcerebralcortexinfection.

Centralnervoussystemvirusinfectionisoneofthemaincausesofchildren’snervoussysteminfectionanddeathallovertheworld.Althoughvaccinationcanpreventmanyseriousdiseasesofthenervoussystemcausedbyviruses(suchaspolio,measlesencephalitis,mumpsmeningoencephalitis,Japaneseencephalitis,etc.),therearestillmanyviralinfectionsthataffectthestructureandfunctionofthecentralnervoussystem.Causeseriousharm.Centralnervoussysteminfectionscausedbyvirusesincludeherpessimplexvirus(HSV)encephalitis,enterovirusinfection,congenitalcytomegalovirus(CMV)infection,humanimmunodeficiencyvirus(HIV)encephalopathy,andmanyothertypes.Theclinicalmanifestationsofcentralnervoussystemviralinfectionsarediverse,withacuteasepticmeningitisorencephalitisbeingthemostcommon.Therearestillsomedifficultiesinthediagnosisoftheetiologyofmostcases.Exceptforafewviruses,thetreatmentofcentralnervoussystemviralinfectionslacksspecificmethods.

Epidemiologie

Centralnervoussysteminfectionscausedbycertainvirusesaffectpeopleofallages,withnoobviousseasonalorregionaldifferences,suchasherpessimplexViralencephalitis.However,someviraldiseaseshaveobviousepidemiccharacteristics.Forexample,arbovirusinfectionstendtooccurintheregionsandseasonswherethearboviruseslive.InChina,Japaneseencephalitismainlyoccursinsummerandautumn(JulytoSeptember),whichisrelatedtothebreedingseasonofitsmainmedia,Culexmosquitoes.Ithasbeenreportedthatabout70%ofviralencephalitisandmeningesoccurredfromJunetoNovember.About50%ofthecasesofviralencephalitisandmeningesoccurredinchildren,andboyswereslightlymoreaffected,withtheratioofmaletofemalebeing1.4:1.Theincidenceofencephalitisishighestinchildrenunder2yearsold,at16.7/100,000,andthelowestinadolescence(15yearsold),at1.0/100,000.Severaltypesofviralinfectionssuchasherpesvirus,enterovirus(exceptpoliovirus)andrespiratoryvirus(suchasadenovirus)accountforthemajorityofthisdisease.Thismayberelatedtomumps,rubella,measles,andpoliointhepastdecade.Itisrelatedtothewidespreadvaccinationoftheinflammatoryvirus.Before1960,mumpsandpoliovirusinfectionsaccountedforabout35%ofcentralnervoussystemvirusinfections.Incountrieswherethetwoviruseshavebeenimplemented,thenumberofpatientshasdecreasedsignificantly.In1992,only4casesofpoliowerereportednationwideintheUnitedStates.WiththeintensivevaccinationofpoliovirusvaccinesinChina,wildvirusinfectionshavebecomerelativelyrare.Thedevelopmentofotherpublichealthwork,suchasquarantine,mosquitocontrol,bloodproductmonitoring,andanimalvectorpreventiveimmunization,hasalsosignificantlyreducedmanytypesofnervoussystemvirusinfections.

Klinická klasifikace

Accordingtothecharacteristicsoftheonsetandcourseofthedisease,viralinfectionsofthenervoussystemcangenerallybedividedintofourcategories:acute,subacute,chronicandembryonicencephalopathy.

Klasifikace virů

Accordingtobiologicalclassificationstandards,classificationshouldreflecttherelationshipbetweenorganismevolutionandphylogeny.Virusclassificationcannotyetbecarriedoutaccordingtothisprinciple.Therearemanyexistingclassificationmethods,andmostofthemaretheclassificationschemeproposedbytheInternationalCommissionforClassificationofViruses(ICTV).Firstlyaccordingtothetypeofnucleicacid,andthenfurtherclassificationaccordingtonucleicacidmolecularweight,structure,symmetrytypeofcapsid,numberofcapsid,envelopeandvirusmorphologyandsize.Scientistshavealsodiscoveredinfectiousagentsthataresmallerthanviruses,calledsubvims,includingviroid,vimsoidandvirino.PrionproteinorprionisaninfectiousproteinthatisresistanttonucleasefirstreportedbyAmericanscholarPrusinerin1982,alsoknownasproteininfector,whichisbelievedtocausemadcow(sheep)diseaseandhumanCJDandThecausativeagentofKurudisease.

Klinické příznaky

Manyvirusescancausenervoussysteminfection,butvariousvirusesmayhavedifferentpathogenicitytodifferentpartsofnervoustissue,soTheclinicalcharacteristicsaredifferent.PathologicalandpathophysiologicalcharacteristicsVirusinfectionsinhumansaremostlythroughtheskin,mucousmembranesorgastrointestinaltract,respiratorytract,andsomecasesareinfectedthroughiatrogenicroutessuchasbloodtransfusionandorgantransplantation.Aftertheinitialreplicationoftheinvasion,thehumanbloodisreleasedtoformviremia,andthenspreadtodistantorgans,especiallythereticuloendothelialsystem,resultinginsystemicsymptomssuchasfever,chills,abdominalpain,diarrhea,rash,orjointpain.Mostofthevirusesthatinvadethenervesenterthenervoussystemthroughthebloodduringthisperiod;afew,suchasrabiesviruses,invadethecentralnervoussystemthroughneuralpathways.Thepropagationofvirusesinnervecellscancausedamagetothecorrespondingcellfunctionsandstimulatethebody'simmuneresponse.Theinflammatoryresponseoflocaltissuestoviralinfectionsincludesanincreaseinlymphocytesandmacrophages,andanincreaseinneutrophilswilloccurifitundergoesanacutecourse.CytokinessuchasIL-1,IL-2,TNF-αandinterferonarealsoinvolvedintheinteractionbetweenthebodyandthevirus,andarerelatedtotheclinicalmanifestationsofinfectionandseriouscomplications.Inviralmeningitis,inflammatorycellsspreadtothepiamaterorsuperficialcortexthroughtheperivascularspace(Virchow--Robinspace),andthecorrespondingneuropathologicalchangesgenerallydisappearnaturallywithoutleavingsequelae.Butasmallnumberofcasescanoccurarachnoiditisorependymitis,blockingthecirculationofcerebrospinalfluidorcausingcerebrospinalfluidabsorptiondisorders,formingobstructiveorcommunicatinghydrocephalus.

Thetypicalneuropathologicalchangesofencephalitisincludepialmeningitis,perivascularleukocyteinfiltration,andmicrogliaproliferationtoformmicroglianodules.Thelocationandseverityoftheselesionsdependonthecharacteristicsofthehostandpathogenicfactors,andtheinfectionsofdifferentcasesanddifferentvirusesareverydifferent.Intheacutephase,thepathologicalchangesmaybemild,oronlymanifestedascerebraledema.Insevereorchronicencephalitis,severepathologicalchangesmayoccur,suchasneuronaldeath,tissuenecrosis,glialhyperplasia,andcysticencephalomalacia.Thepathologicalfeaturesofencephalomyelitisafterinfectionaremostlyedema,demyelinationaroundtheveinandinflammationofmononuclearcells.

Vrozená virová infekce nervového systému (také známá jako nitroděložní infekce nebo embryonální encefalopatie) má mnoho typů projevů, které mohou být mírným vývojem neurologických defektů nebo vážnou nekrotizující meningesencefalitidou. ingitisvirus);②subependymalstromalcelllysis (zarděnkový virus,CMV);③nocerebralgyrus (CMV);④periventrikulární změkčení bílé hmoty (CMV,Rubellavirus,HSV,HIV, VZV);⑤Hydrostatická encefalie (HSV, CMV, VZV, virus venezuelské encefalitidy);⑥Cysticencefalomalacie (HSV), CMV, VZV) atd.

Geneticdefect

Perhapsmetabolicdiseasesthataffectthenervoussystem(suchasphenylpropionicaciduria,glycogenstoragedisease,mucopolysaccharidosis,lipidstoragedisease),degenerativedisease(Suchasleukodystrophy,Parkinson'sdisease,amyotrophiclateralsclerosis,hereditaryopticatrophy,etc.)andmyopathy(suchasprogressivemusculardystrophy)aregeneticdiseases.Mostoftheinheritanceisautosomalrecessive.Theperiodicparalysisofhyperkalemiaandhypokalemiaisinheritedinanautosomaldominantmanner.

NutritionalDisorders

PatientswithKwahioko'sdisease(atypeofproteinthermalmalnutrition)mayhaveneurologicalsymptomssuchastremor,slowmovement,andmyoclonus.VitaminAdeficiencyorpoisoningcancauseintracranialhypertension.VitaminBdeficiencycanaffectthenervoussystem.Forexample,vitaminB1deficiency(beriberi)ismanifestedasmostperipheralnervedamage,andvitaminB12deficiencycancausesubacutecombineddegeneration.

Nemoci centrálního nervového systému způsobené alkoholem

Wenike’sencephalopathy:Itisanacutedystrophicneurologicaldiseasecausedbylong-termalcoholism.Itcanalsooccurinothersituations,suchaschronicnutritionaldeficiencies,chronicwastingdiseases,andgastrointestinaldiseases.Mainlyduetothiamine(vitaminB1)deficiency.Thelesionsmainlyinvolvethethalamus,hypothalamus,papillarybodyandthethirdventricle,graymatteraroundthemidbrainaqueduct,andthebottomofthefourthventricleandthecerebellum.ThepathologicalchangesofacuteWynekencephalopathyaremainlyextensivespottinghemorrhageintheaboveparts,thatis,hemorrhage,necrosisandsofteningaroundthefourthventricleandsurroundinggraymatteroftheaqueduct,thalamusandotherparts,andlossofnervecellaxonandmyelinsheath.SubacuteWinnickencephalopathymayhavecapillaryincreaseandexpansion,cellproliferationandsmallhemorrhagicfoci,accompaniedbyneuronaldegenerationandmicroglialproliferation,andmacrophagereaction.ChronicWynnick'sencephalopathymayhaveatrophyofthepapillarybody,brownspongy,lossofparenchymalcomponentsinthelesionarea,activeastrocyteresponse,andoldsmallhemorrhagicfoci.

Alcoholictremor:oralcoholwithdrawaltremor,isthemostcommonmilderalcoholwithdrawalsyndrome.Itsoccurrenceisbelievedtoberelatedtotheexcessiveexcitementofcentralandperipheralnerveadrenergicreceptorsafteralcoholwithdrawal.Generally,theonsetis6-24hoursafterreducingalcoholconsumption.Tremorsoftenoccurinthemorning.Thefrequencyandintensityoftremorareirregular,andtheyweakenwhentheyarequiet,andaggravatewhenexerciseoremotionalstress.

Alcoholicepilepsy:alsoknownasrumseizures,referstothegeneralizedseizuresofseverealcoholismpatientswhodrinkalotofalcoholforacertainperiodoftimeafterasuddeninterruptionofdrinking.Itsoccurrencemayberelatedtothesharpchangeinbloodalcoholconcentrationafterweaning,whichcausedthedecreaseofserummagnesiumandpotassiumionconcentrationandtheincreaseofarterialbloodpH.Convulsionsusuallyoccurwithin48hoursafterabstinencefromalcohol.Iftheyoccurafter96hours,theyshouldbeconsideredasnon-abstinenceconvulsions.Theformofseizuresisgeneralizedtonic-clonicconvulsions,accompaniedbydisturbancesinconsciousness.Otherseizuresarealmostnon-existent,andseldomcontinuousseizures,withoccasionalstatusepilepticus.Thepatientmayhavewithdrawalsymptomssuchastremor,sweating,anddeliriumbeforetheattack,andtherearegenerallynofocalsymptomsandsignsatthetimeoftheattack.TheremaybetransientrhythmdisturbancesintheEEGduringtheactiveepilepticperiod,andtheremaybeparoxysmalsharpwavereleaseandslowerrhythm,butitcanquicklyreturntonormalwithinafewdaysafterstoppingdrinking.Deliriumtremor:referstoanacuteencephalopathysyndromethatoccursonthebasisofchronicalcoholism.Itmostlyoccursinalcohol-dependentpatientswhocontinuetodrinkalotofalcohol.Itcanbetriggeredbyfactorssuchastraumaandinfectionthatweakenthebody'sresistance.Itusuallyoccurssuddenly3to5daysaftergivingupdrinking,anditismainlymanifestedassevereconfusion,lossoforientation,vividdelusionsandhallucinations,accompaniedbytremor,anxiety,insomnia,andsympathetichyperactivity,suchasdilatedpupils,fever,Increasedbreathingandheartbeat,increasedordecreasedbloodpressure,andprofusesweating.Hallucinationsareoftenillusions,andthecontentismostlysmallanimals,suchassnakesandmice,andsomecanbequitevividandlifelike.

Alcoholicbrainatrophy:referstothereductionofbraintissuevolumeanddysfunctioncausedbychronicalcoholism.Itspathogenesisisunknown,anditmayberelatedtothedirectdamageofalcoholtothebrainandnutritionaldisorders,especiallythelackofvitaminB1.Itismorecommoninmiddle-agedandelderlymenwhodrinkalotofalcoholforalongtime.Theonsetishiddenandprogressesslowly.Anxiety,headaches,insomniaandfatiguearecommonintheearlystage,andtherearegraduallymentaldeclineandpersonalitychanges,whicharemanifestedbyobviouslossofmemory,declineincalculationability,judgmentandanalysisability,andafewcanhaveforgetting,fictionanddisorientation.Personalitychangescanincludeselfishness,undisciplinedlife,emotionalinstability,irritability,lowworkefficiency,lackofresponsibility,disobediencetoadvice,andtensionininterpersonalrelationships.Inaddition,somepatientsmayalsohaveperipheralneuropathy,muscleatrophy,andevenseverealcoholismsuchastremors,hallucinations,delusions,andseizures.HeadCTshowedsymmetricalenlargementofthelateralventricle,brainatrophy,suchaswideningofthesulci,interhemisphericfissure,andsylvianfissure.Alcoholiccerebellardegeneration:Referstothedegenerationofthecerebellarcortexcausedbylong-termheavydrinking.Themechanismisunclear,anditisthoughtthatitmayberelatedtoneurotrophicdisorders.Thelesionsaremainlyconfinedtothecerebellarvermis,andcanextendtotheanteriorlobeinthelaterstage.Mostpatientshavesubacuteorchroniconset.Therearesignificantlymorementhanwomen,andtheonsetoftenoccursaftermiddleage.Mainlymanifestedasataxiaofthelowerlimbsandtrunk,unsteadywalkingorclumsymovements,whilegaitandstandingareunusuallycommon.Inthebeginning,theturningisunstable,anditisdifficultorimpossibletowalkinastraightline.Gradually,thefeetwideninwalking,showingadrunkengait,hesitatingtowalk,anddifficultyinstanding.Therewasapositiveheelkneeshintestatthetimeofexamination.Theupperlimbsareoftenunaffected,andnystagmus,dysarthriaandhandtremorsarerare.Mostpatientsdevelopprogressively,andthenremainstaticformanyyears.Insomepatients,thecerebellarsymptomsdevelopinaleapingmanner,andthesymptomsoftenincreasesignificantlyafterinfection.Itcanbecombinedwithpolyneuropathy,roughtickdiseaseandbrainatrophy.CTorMRIalsohasatrophyofthecerebellarvermis.

Others

Theperipheralnervoussystem(Englishnameperipheralnervoussystem,PNSforshort)isthenervethatissentoutbythecentralnervoussystemandleadstovariouspartsofthehumanbody.Itisalsocalledtheperipheralnervoussystem(peripheralnervoussystem).):Accordingtothedifferentpartsconnectedtothecenter,itcanbedividedintothecranialnervesconnectedtothebrainandthespinalnervesconnectedtothespinalcord;itcanalsobedividedintothesomaticnervoussystemandthevisceralnervesaccordingtothedifferentdistributionobjects.Theperipheralnervoussystemisresponsibleforcommunicationwithallpartsofthebody,andplaystheroleofincomingandoutgoinginformation.

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