Ziziphi iiSeli zeGlial kunye Nento abayenzayo?

by Adrienne Dellwo

Ezinye iiseli zeBrain

Mhlawumbi uvile nge "grey" yengqondo, eyenziwe ngamaseli abizwa ngokuba ngama-neurons, kodwa uhlobo oluncinci lwengqondo yeselingo yinto eyenza "into emhlophe." Ezi zibizwa ngokuba ngama-glial cells.

Ziziphi iiSeli zeGlial?

Ekuqaleni, iiseli ze-glial-ezibizwa ngokuba yi-glia okanye i-neuroglia-zazikholelwa ukuba zinikezela ngenkxaso. Igama elithi "glia" ngokwezwi nezwi lithetha "i-neural glue." Kodwa ukufumanisa okwakutshanje, kuye kwafumanisa ukuba benza zonke iintlobo zemisebenzi kwingqondo kunye neentsholongwane ezihamba emzimbeni wakho. Ngenxa yoko, uphando luye lwaqhuma kwaye sifunde imiqulu ngabo. Sekunjalo, kuninzi okushiyiweyo ukufunda.

Iintlobo zamaGlial cell

Ngokukodwa, iiseli ze-glial zinika inkxaso ye-neurons. Cinga ngabo njengeziko lokubhala le-nervous system, kunye ne-janitorial kunye nabasebenzi bokugcina. Akunakwenza imisebenzi emikhulu, kodwa ngaphandle kwabo, loo misebenzi emikhulu ayayi kuze yenziwe.

Iiseli ze-Glial zivela kwiifom ezininzi, ngamnye owenza imisebenzi ethile ethile egcina ingqondo yakho isebenze ngokuchanekileyo-okanye kungenjalo, ukuba unesifo esichaphazela le iiseli ezibalulekileyo.

Inkqubo yakho ye-nervous central (CNS) yenziwe ngengqondo yakho kunye neentsholongwane zakho. Iintlobo ezintlanu ezikhoyo kwi-CNS yakho zi:

Astrocytes
IOligodendrocytes
Microglia
Ependymal cells
Radial glia

Kananjalo unayo iiseli zesiganeko kwinkqubo yakho ye-nervous system (PNS), equlethe iimbilini kwiimpembelelo zakho, kude nomgudu. Iindidi ezimbini zeellial cells zilapha:

ZeSwitwan
Iiseli zeSatellite

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Astrocytes

NANCY KEDERSHA / UCLA / ISAYENSI IFOTO LIBRARY / Getty Izithombe

Uhlobo oluqhelekileyo lweseli ye-glial kwinkqubo yesantya ephakathi yintsikroti, ebizwa ngokuba yi-astroglia. I-"astro" inxalenye yegama ngenxa yokuba ibhekiselele ekubeni ibukeka njengeenkwenkwezi, kunye neziqalo eziphuma kuyo yonke indawo.

Ezinye, ezibizwa ngokuba yi-astrocytes protoplasmic, zineziqulatho ezininzi ngamasebe amaninzi. Ezinye, ezibizwa ngokuba yi-astrocytes ezinobumba zide zide, iingalo ezinqabileyo ezisebenza rhoqo. Uhlobo lwe-protoplasm lufumaneka ngokubanzi phakathi kwee-neurons kwimiba ebomvu ngelixa i-fibrous ifumaneka kumbandela omhlophe. Nangona kule mihluko, benza imisebenzi efanayo.

Ii-astrocytes zinemisebenzi emininzi ebalulekileyo, kuquka:

Ukwenza umqobo we-blood-brain barrier (BBB). I-BBB injengeenkqubo ezikhuselekile zokukhusela, ukuvumela kuphela izinto ezifunekayo kwi-brain yakho xa ugcina izinto ezinokulimaza. Le nkqubo yokucoca ibalulekile ekugcineni ingqondo yakho iphilile.
Ukulawula iikhemikhali ezijikeleze i-neurons. Indlela yokuthetha nge-neurons ihamba ngezithunywa zamakhemikhali ezibizwa nge-neurotransmitters. Emva kokuba ikhemikhali ihambise umyalezo wayo kwisisele, ngokuqinisekileyo ihleli apho izinto ezixubhayo kuze kube yilapho i-astrocyte iphinda ibuyisele kwakhona inkqubo ebizwa ngokuba yi- reuptake . Inkqubo yokubuyisela kwakhona iinjongo zamachiza amaninzi, kubandakanya abachasayo. I-Astrocytes ihlambulula kwakhona oko kushiywe emva kokuba i-neuron ifa, kunye ne-ion potassium ezingaphezulu, eziyimichiza edlala indima ebalulekileyo kwimisebenzi yesigulane.
Ukulawula ukuhamba kwegazi ukuya kwingqondo. Ukuze ingqondo yakho iqhube kakuhle ulwazi, idinga inani elithile legazi eliya kuyo yonke imimandla yalo. Ummandla osebenzayo ufumana ngaphezu kokungasebenzi.
Ukuvumelanisa umsebenzi weexons. Iimvumi zide, iinxalenye ze-neurons kunye neeseli zamagulane ezenza umbane ukuthumela imiyalezo esuka kwelinye iseli kwenye.

I-astrocyte i-dysfunction iye yaxhamla kwiintlobo ezininzi zezifo ezenza i-neurodeergenerative, eziquka:

Iimpawu zezilwanyana zezifo ezinxulumene ne-astrocyte zibanceda abaphandi bafunde kabanzi malunga nethemba lokufumana unyango olutsha.

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IOligodendrocytes

I-Oligodendrocytes zivela kwiiselingi ze-neural stem. Igama liqulethwe ngamaGrike athi, ngokubonke, lithetha "iiseli ezinamagatsha amaninzi." Injongo yabo ephambili kukunceda ulwazi luhambe ngokukhawuleza kunye ne-axon.

I-Oligodendrocytes ibonakala njengeebhola ze-spikey. Kwiingcebiso zeepikhi zabo zimhlophe, izibilini eziqhambileyo ezijikeleza ii-axon kwiiseli zesisongela. Injongo yabo kukukwakheka kwinqanaba lokukhusela, njengento yokufakelwa kwiplastiki kwiinkambo zombane. Olu liseko lokhuselo lubizwa ngokuba ngumthi we-myelin.

Ingxowa ayiqhubekanga, nangona kunjalo. Kukho umda phakathi kwebhubhane ngalinye elibizwa ngokuba yi "node ye Ranvier," kwaye iyona node eyanceda izibonakaliso zombane zisasazeka ngokufanelekileyo kwiiseli zesisongom. Isalathisi sisuka kwi-node enye ukuya kwesinye, esenza ukunyuka kwe-nerve conduction ngeli xesha kunye nokunciphisa amandla athathathekayo ukuyihambisa. Izibonakaliso kunye nemisipha ye-myelinated zihamba ngokukhawuleza njengeeekhilomitha ezingama-200 ngesibini.

Xa uzalwa, unamabhola ambalwa kuphela, kwaye inani lalo liqhubeka likhula de ube malunga nama-25 ukuya ku-30 ubudala. I-Myelination ikholelwa ukuba ibamba indima ebalulekileyo kwiingcaphephe.

I-Oligodendrocytes inikezela nokuzinza kwaye ithwala amandla avela kwiiseli zegazi ukuya kuma-axons.

Igama elithi "myelin sheath" lingaqhelana nawe ngenxa yokudibanisa ne- multiple sclerosis . Kuloo sifo, kukholelwa ukuba umzimba womzimba uhlasele i-myelin sheaths, ekhokelela ekusebenziseni i-neurons kunye nokukhubazeka kwengqondo. Ukulimala kwentambo yomgudu kungabangela umonakalo kwi-myelin sheaths.

Ezinye izifo ezikholelwa ukuba zinxulumene nokungasebenzi kwe-oligodendrocyte ziquka:

Leukodystrophies
Amathumba abizwa nge- oligodendrogliomas
Schizophrenia
Ukuxhuzula

Olunye uphando lubonisa ukuba i-oligodendrocytes ingonakaliswa yi-glutamate ye-neurotransmitter, leyo, phakathi kweminye imisebenzi, ivuselela indawo yengqondo yakho ukuze ukwazi ukugxila nokufunda ulwazi olutsha. Nangona kunjalo, kumanqanaba aphakamileyo, i-glutamate ithathwa ngokuba yi "excitotoxin," oku kuthetha ukuba inokugqithisa iiseli ade ife.

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Microglia

Njengoko igama labo libonisa, i-microglia yileli elincinane iiseli ze-glial. Benza njengendlela yokuzikhusela yomzimba, oko kuyimfuneko kuba i-BBB ihlukanisa ingqondo evela emzimbeni wakho wonke.

I-Microglia iqaphele kwiimpawu zokulimala kunye nezifo. Xa beyifumene, bahlawula kwaye banakekele ingxaki-nokuba ithetha ukuhlutha iiseli ezifile okanye ukulahla i-toxin okanye i-pathogen.

Xa bephendula ngokulimala, i-microglia ibangela ukuvuvukala njengenxalenye yenkqubo yokuphilisa. Kwezinye iimeko, ezifana nesifo se-Alzheimer , banokuthi baqhutywe ngamandla kwaye babangele ukuvuvukala. Kukholelwa ukuba kuholele kwiiplanga ze-amyloid kunye nezinye iingxaki ezihambelana nesi sifo.

Ngokuhambisana ne-Alzheimer's, izifo ezinokuthi zidibaniswe nokukhubazeka kwe-microglial ziquka:

I-Microglia ikholelwa ukuba inemisebenzi emininzi ngaphaya koko, kuquka imisebenzi kwi-plasticity edibeneyo yokufunda kunye nokukhokela ukuphuhliswa kwengqondo, apho banomsebenzi obalulekileyo wokugcina indlu.

Ubunzima bethu budala ubudlelwane obuninzi phakathi kweeurons ezivumela ukuba badlulise ulwazi emva nangaphambili. Enyanisweni, ubuchopho budala izinto ezininzi kunokuba sifuna, ezingenakusebenza. I-Microglia ifumanisa i-synapses engadingekile kwaye "iyakuthabathela", njengokuba umgadi waselungisa i-rose bush ukuze aphile.

Uphando lwe-microglial luye lwacinywa ngokwenene kwiminyaka yamuva, ekhokelela ekuqondeni okwandayo kwendima yabo kwimpilo kunye nezifo kwinkqubo yesantya ephakathi.

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Ependymal Cell

Ii-cell ze-Ependymal ziyaziwa ngokwenza i-membrane ebizwa ngokuba yi-ependyma, enomgca omncinci onobumba ophakathi kwintambo yomgca kunye nemigodi yokuhamba. Zenza kwakhona i- cerebrospinal fluid .

Iiseli ze-Ependymal zincinci kakhulu kwaye zidibanisa ngokubambisana ukuze zenze i membrane. Ngaphakathi kweefrijiki, zine-cilia, ezibukeka njengezinwele ezincinane, ezijikeleza emva nangaphezulu ukuze zenze i-cerebrospinal fluid ijikeleze.

I-Cerebrospinal fluid inikezela izondlo kunye nokuphelisa imveliso yengcola ukusuka kwingqondo kunye nomqolo womgca. Kwakhona isebenza njengento yokutya kunye nokuxhalabisa phakathi kwengqondo yakho kunye nekrele. Kwakhona kubalulekile ukuba i-homeostasis yengqondo yakho, oku kuthetha ukulawula ukushisa kwayo kunye nezinye izinto eziqhubekayo zisebenza ngokusemandleni.

Iiseli ze-Ependymal nazo zibandakanyeka kwi-BBB.

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Radial Glia

I-Radial glia ikholelwa ukuba yintlobo yesalente ye- stem , oku kuthetha ukuba idala ezinye iiseli. Kwiqondo elikhulayo, "ngabazali" bama-neurons, astrocytes, kunye ne-oligodendrocyte. Xa ubengumntwana, babonelela nge-scaffolding yokuphuhlisa i-neurons, ngenxa yemibhobho ende ekhokela iiseli ezincinci zobuchopho endaweni yakho njengoko i-brain yakho ifom.

Indima yabo njengama-stem cells, ngokukodwa njengabadali be-neurons, yenza ukuba kugxininiswe kuphando malunga nendlela yokulungisa umonakalo wengqondo kwisifo okanye ukulimala.

Kamva ebomini, badlala indima kwi-neuroplasticity.

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Schwann Iiseli

Iiseli zeSchwann zibizwa ngokuba yi-physologist u-Theodor Schwann, owazifumanisa. Zisebenza okuninzi njenge-oligodendrocytes kuba zibonelela i-myelin sheaths ze-axons, kodwa zikhona kwinkqubo ye-nervous system (PNS) kunokuba i-CNS.

Nangona kunjalo, kunokuba ube yiseli ephakathi kunye neengalo zomgca, i-Schwann zenza i-spirals ngqo ngqo nge-axon. Amanqaku kaRarvier alala phakathi kwabo, njengokuba enza phakathi kweembrane ze-oligodendrocytes, kwaye zincedisa ukuhanjiswa kweenthambo ngendlela efanayo.

Iiseli zeSchwann nazo ziyinxalenye yesistim somzimba sika-PNS. Xa isalathisi yesigulane ibonakaliswe, banako ukukwazi ukutya i-axon ye-nerons kunye neendlela ezikhuselweyo ze-axon entsha.

Izifo ezibandakanya amaseli eSchwann ziquka:

I-Guillain-Barre 'syndrome
Isifo seCharcot-Marie-Tooth
Schwannomatosis
Isifo esingapheliyo sokutshatyalaliswa kwezinto ezinokudambisa i-polyneuropathy
Neqhenqa

Senze uphando oluthembisayo malunga nokufakelwa kweeseli zeSwitwan zenzelwa ukulimala kwentambo yomgudu kunye nezinye iintlobo zomonakalo wentsholongwane.

Iiseli zeSchwann nazo zibandakanyeka kwezinye iintlobo zentlungu engapheliyo. Ukusebenza kwabo emva kokuba umonakalo wamantongomane unokuba negalelo ekusebenziseni ukungasebenzi kwihlobo lweentambo zesibindi ezibizwa ngokuthi i- nociceptors , ezona yimiba engqongileyo efana nokushisa nokubanda.

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Iiseli zeSatellite

Iiseli zeSatellite zifumana igama labo ngendlela eyajikeleza i-neurons ethile, kunye nama-satellites amaninzi enza i-sheath ecaleni kwamaselula. Siqala ukufunda malunga nale seliyi kodwa abaphandi abaninzi bakholelwa ukuba bafana neenkwenkwezi.

Injongo ephambili yeeseli zeSatellite ibonakala iyimigaqo yokusingqongileyo kwi-neurons, ukugcina iikhemikhali ngokulinganisela.

I-neurons eziseli-satellite cells zenza into ebizwa ngokuba yi-gangila, eyoyiqoqo leeseli zesigulane kwi-system ye-nerveous autonomic kunye ne-sensory system. Inkqubo ye-neon autonomic ilawula iziphathamandla zangaphakathi, ngelixa i-system yakho yentsingiselo ikuvumela ukuba ubone, ukuva, ukuhogela, ukuthintela, kunye nokutya.

Iiseli zeSatellite zihambisa ukutya okunomsoco kwi-neuron kwaye zithatha i-toxins enzima zensimbi, ezifana ne-mercury kunye nekhokelo, ukuba zingabonakalisi i-neurons.

Bakholelwa ukuba bancedisa ukuthutha ii-neurotransmitter eziliqela kunye nezinye izinto, kuquka:

Glutamate
GABA
Norepinephrin
Adenosine triphosphate
Izinto P
ICapsaicin
Acetylcholine

Njenga-microglia, iiseli ze-satellite zibona kwaye ziphendule kwingozi kunye nokuvuvukala. Nangona kunjalo, indima yabo ekulungiseni umonakalo weseli akaqondwa kakuhle.

Iiseli zeSatellite zixhomekeke ekubandezelekeni okungapheliyo okubandakanya ukulimala kwamathambo, ukulimala kwentsholongwane, kunye nokuphakanyiswa kweentlungu (hyperalgesia) ezinokubangelwa yi-chemotherapy.

ILizwi

Ininzi yale nto esiyayaziyo, sikholwa, okanye sikrokre malunga neeseli zesiganeko ngolwazi olutsha. Ezi iiseli zisinceda siqonde indlela ubuchopho busebenza ngayo noko kwenzeka ntoni xa izinto zingasebenzi njengoko zifanelekile.

Kuqiniseke ukuba sinokuningi ukufunda malunga ne-glia, kwaye sinokufumana unyango olutsha kwizifo ezininzi njengoko i-pool yethu yolwazi ikhula.

> Imithombo:

> Gosselin RD, Suter MR, Ji RR, Decosterd I. Iilli zeGlial kunye nentlungu engapheliyo. Neuroscientist. 2010 Oct; 16 (5): 519-31.

> Kriegstein A, uAlvarez-Buylla A. Ubume be-glial bamaseli angama-embryonic and adult neural stem cells. Ukuphononongwa ngonyaka nge-neuroscience. 2009; 32: 149-84.

> Ohara PT, i-JP, iBhargava A, uJasmin L. Ubungqina bendima yeConnexin 43 kwi-Trigeminal Pain Ukusebenzisa i-RNA Ukungena kwi-Vivo. Umbhalo we-neurophysiology. 2008 Dec; 100 (6): 3064-73.