Information
Neuronshaveavarietyofshapes,buttheycanallbedividedintocellbodiesandprocesses.Thesizeofthecellbodyvariesgreatly,thesmalldiameterisonly5-6μm,thelargeonecanreachmorethan100μm,andtheshape,numberandlengthoftheprotrusionsarealsoverydifferent.Therearetwotypesofneuronalprocesses:dendritesandaxons.Dendritesaremostlytree-likebranches,whichcanreceivestimulationandtransmitimpulsestothecellbody;axonsarefilamentousandoftenhavebranchesattheends,whicharecalledaxonterminals.Axonstransmitimpulsesfromthecellbodytotheterminal.Usuallyaneuronhasoneormoredendrites,butonlyoneaxon.Thelargerthecellbodyofaneuron,thelongeritsaxon.Generallyspeaking,dendritesareshorterthanaxons.Thereareseveralclassificationsofneurons.Neuronscanbedividedintothreetypesaccordingtothenumberofprotrusions:
①Multipolarneurons,withoneaxonandmultipledendrites;
②BipolarNeuronshavetwoprotrusions,oneisdendritesandtheotherisaxons;
③Pseudo-unipolarneurons,whichemitaprotrusionfromthecellbody,whichisnotfarfromthecellbodyandpresentsa"T"-shapedsplitTherearetwobranches,oneorgandistributedtoothertissuesontheperipheryiscalledtheperipheralprocess;theotherbranchentersthecentralnervoussystemandiscalledthecentralprocess.Thesetwobranchesofpseudo-monopolarneurons,accordingtothedirectionofnerveimpulseconduction,thecentralprocessisaxons,andthesurroundingprocessesaredendrites;butthesurroundingprocessesarethinandlong,similarinshapetoaxons,sotheyareoftenreferredtoasaxons.
Accordingtothelengthofaxons,neuronscanbedividedinto:
①Largeneuronswithlongaxons,calledGolgitypeIneurons,thelongestTheaxonsaremorethan1m;
②SmallneuronswithshortaxonsarecalledGolgitypeIIneurons,andtheaxonsareonlyafewmicronsshort.
Accordingtothefunctionoftheneuron,itcanbedividedinto:
①Sensoryneurons,orafferentneurons,aremostlypseudo-monopolarneurons,cellbodiesItismainlylocatedinthecerebrospinalganglia,andtheperipheralprotuberancesaredistributedintheskinandmuscles.Theyreceivestimulationandtransmitthestimulationtothecenter.
②Motorneurons,orefferentneurons,aremostlymultipolarneurons.Thecellbodyismainlylocatedinthebrain,spinalcordandautonomicganglia.Ittransmitsnerveimpulsestothemusclesorglandstoproduceeffects.
③Interneuronsarebetweenthefirsttwotypesofneurons,andmostofthemaremultipolarneurons.Themoreanimalsevolve,themoreinterneurons.Interneuronsinthehumannervoussystemaccountforabout99%ofthetotalnumberofneurons,formingacomplexnetworkinthecentralnervoussystem.
Accordingtotheneurotransmitterreleasedbytheneuron,orneuromodulator,itcanbedividedinto:①cholinergicneuron;②aminergicneuron;③peptidergicneuron;④aminoacidicneuron.
Relatedinformation
Neurons:Neuronsarenervecells,whicharehighlydifferentiatedcells.Theyhavethefunctionsofsensingstimuli,conductingimpulsesandintegratinginformation,andarethemorphologicalstructureandfunctionofthenervoussystemThebasicunitof2,themorphologicalstructureofneurons:neuronsarecomposedoftwoparts:cellbodiesandprocesses.3,classificationofneurons:(1)Classificationbythenumberofneuronprocesses:unipolarneurons,bipolarneurons,Multipolarneurons(2)areclassifiedaccordingtoneuronfunction:sensoryneurons(afferentneurons),motorneurons(efferentneurons),contactneurons(interneurons).(二)nervefiber:nerveFibersarecomposedofaxonsofmotornervesorlongdendritesofsensoryneurons(bothcollectivelyreferredtoasaxons)andglialcellsthatsurroundit.nervefibersaredividedintomyelinatednervefibersandunmyelinatednervefibers.