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•Neuron:•Supportingcells:–CNS:neuroglia(glia)–PNS:Schwanncellsandsatellitecells–Functions:•physicalsupport•electricalinsulation•metabolice

xchange•blood-brainbarrierCompositionofNervousTissueTypesandFunctionsofGliaNameofGlialCellFunctionAstrocyte(As

troglia)Star-shapedcellsthatprovidephysicalandnutritionalsupportforneurons:1)cleanupbrain"debris";2)transp

ortnutrientstoneurons;3)holdneuronsinplace;4)digestpartsofdeadneurons;5)regulatecontentofextracellularspaceMicrogliaLikeastrocytes,microgliadig

estpartsofdeadneurons.Oligo-dendrogliaProvidetheinsulation(myelin)toneuronsinthecentralnervoussystem.SatelliteCellsPhysicalsupporttoneuro

nsintheperipheralnervoussystem.SchwannCellsProvidetheinsulation(myelin)toneuronsintheperipheralnervoussystem.NeurogliaintheCNS•Ab

letoreplicate!•ImportanceinnervoussystemfunctionisVASTLYunderestimated!•Evidenceismounting:1.Nurturingrole2.Signalingrole

(Memory?)3.Inflammation4.Pain5.Manymoretoe!Neuroglia:DistinguishingFeatures1.Presenceoftightjunctionsbetweentheendothe

lialcells2.Oneofthenotablefeaturesofendothelialcellsinparisontoothercellisthelackofpinocyticvesicles3.Selectivepermeabilityt

omoleculesbasedontheirmolecularweightandlipidsolubility4.Presenceofspecificmarkers•Richintwoenzymes:gammaglutamyltranspeptidase(GGTP)(forami

noacidtransport)andalkalinephosphatase(transportofphsopahteions)usedasmarkerforBBB.•Others:glucosetra

nsporter(GLUT-1);endothelialbarrierantigen(EBA;unknownfunction)andantigenrecognizedbytheMRCOX-47monoclonalantibody(importantforcell-

to-celladhesion);transferrinreceptor(transportofferricions).PropertiesofBloodBrainBarriersBBB1.NeuronshaveTWO"processes"calledaxonsanddendri

tes.GlialcellsonlyhaveONE.2.NeuronsCANgenerateactionpotentials.GlialcellsCANNOT,however,dohavearestingpoten

tial.3.NeuronsHAVEsynapsesthatuseneurotransmitters.GlialcellsdoNOThavechemicalsynapses.4.NeuronsdoNOTcontinuetodivide.GlialcellsDOcontinuetodivide.5.

TherearemanyMORE(10-50timesmore)glialcellsinthebrainparedtothenumberofneurons.Gliaaredifferentfromneurons:NerveCellsNeurons,Glia,ExtracellularSpace,a

ndBloodBidirectionalCommunicationPartnersintheCNS•Receivingsignalsfromneighboringneuronsandrespondingtothemwithreleaseofneur

oactivesubstances•Expressreceptorsforalmostallneurotransmittersandneuromodulators•Increaseofintracellularcalciumconcentration•Membra

nedepolarizationinastrocytesaremonresponsestoneuralactivity•MetabolicallycoupledtoneuralactivityMetabolismofAstrocytesandtheirMetabolicCoop

erationwithNeurons•Glucose•Aminoacidmetabolism•Enzymes:•glutaminesynthetase(glutamate-glutaminecycle);•glycogenphosphorylatase(glycogenmo

bilization);•pyruvatecarboxylase(anapleroticsynthesisofoxaloacetate);•cysteinesulfinatedecarboxylase(s

ynthesisoftaurine);•glycinecleavagesystem,glycinemetabolism.•ThreeTypesofMetabolicCooperationofAstrocytesandNeurons1.Supplyof

theenergysubstratelactatetoneurons2.Therecyclingofneuronalglutamatebytheglutamate-glutaminecycle3.Thesupplybyastrocytes

ofprecursorsforneuronalglutathione(GSH)synthesis