Le myelin esingxotyeni of luvo: umsebenzi wobuyiselo

Inkqubo luvo woMntu kunye eziziivethebreyithi abe isicwangciso esinye zesakhiwo wasondeza iziko - ingqondo kunye umnqonqo, kunye nezahlulo neuropathy - unyenyisa ukusuka imizimba engundoqo ye-luvo, nenika iinkqubo ze iiseli zemithambo-luvo - iiseli zemithambo-luvo.

iifom zazo iseti zobuchopho, imisebenzi engundoqo apho excitability kunye conductivity. Ezi propati zicacisiwe sibonakale ngaphezulu kunazo zonke iimpawu noshowo inwebu neuronal kunye waso zabo, kuqulethe into ekuthiwa myelin. Kweli nqaku siza kujonga isakhiwo kunye Umsebenzi weli ezimbaxa, kwakunye ufumane iindlela kunokwenzeka ukubuyisela kuyo.

Kutheni neurocytes kunye neenkqubo ezinikezelwa yi-myelin

Ngoko ke akukho axons ngephutha kunye luvo kufuneka umaleko olukhuselayo eziquka izakhiwo lipid-protini. Isibakala sokuba eli ziko yinkqubo eziphilayo, olusekelwe phezu amaza kagesi buthathaka. Xa umsinga wombane uya uhamba ngocingo, esi sokugqibela sona kufuneka ugqunywe zokwambathisa izinto ukunciphisa ukusasaza pulses zombane kunye nokuthintela ukuncipha kul. Imisebenzi efanayo ifayibha luvo ethwele esingxotyeni myelin. Ngaphezu koko, inkxaso, kwaye ibonelela ukutya ifayibha.

Le khemikhali Ukubunjwa myelin

Njengoninzi imifinya iseli, yinto uhlobo lipoprotein. Ngaphezu koko, umxholo amanqatha phezulu kakhulu - ukuya kwi-75%, kwaye iiproteins - 25%. Myelin ngezixa ezincinane kwakhona iquka glycolipids kunye glycoproteins. nokubunjwa kwayo chemical yahlukile kwi-luvo nomqolo kunye cranial.

Ekuqaleni kukho umxholo aphezulu phospholipids - ukuya kutsho kuma-45%, kwaye ezinye uvela cholesterol kunye cerebrosides. Demyelination (ngamanye myelin replacement for ezinye izinto kwiinkqubo luvo) kukhokelela kwizifo ezifana ngokuqatha samathambo, ezifana multiple.

Ukusuka kwindawo lwemichiza lwembono, le nkqubo iza kukhangela ngolu hlobo: esingxotyeni salo myelin of luvo ukutshintsha isakhiwo sayo, nto leyo ngokuyintloko wabonakalaliswa ekuncipheni ipesenti umxholo lipid ngokunxulumene kwiiproteni. Ngokubhekele phaya nokunciphisa ubungakanani cholesterol kunye nesiqulatho lamanzi. Kwaye konke oku kukhokelela endaweni yokupasa myelin equlethe oligodendrocytes okanye iiseli Schwann kwi macrophage, astrocytes kunye ulwelo intercellular.

Isiphumo yezi nguqu kwemichiza kuya kubakho ukuhla elibukhali kwi isakhono axons ukuqhuba ukuphazamiseka de uvimba ngokupheleleyo lokudlula azilawule-luvo.

Iimpawu iiseli neuroglial

Njengoko sele kukhankanyiwe, lisesingxobeni myelin of axons kunye luvo amiliswe kunye izakhiwo ezizodwa, lubonakala nezinga eliphantsi permeability ukuba sodium kunye calcium ion, yaye ke ngoko nekhono yokuphumla kuphela (abakwazi ukuqhuba inkqubela-luvo aze aqhube umsebenzi zombane).

Ezi zithinteli ekuthiwa ziiseli glial. Ezi ziquka:

• oligodendrocytes;
• astrocytes ezinezikhondo;
• iiseli ependymal;
• astrocytes plasma.

Bonke bephela akhiwa umaleko olungaphandle umbungu - le ectoderm yaye igama eliqhelekileyo - macroglia. Glia luvo enovelwano, parasympathetic kunye somatic zimelwe Schwann iiseli (neyrolemmotsitami).

Ubume kunye nomsebenzi oligodendrocytes

Bona ziyinxalenye yenkqubo luvo kwaye iiseli macroglia. Ekubeni myelin - isakhiwo protein-lipid, oko kwandisa izinga excitation. Iiseli ngokwabo uzakhela umaleko ngombane zokwambathisa of kwalapho ebuchotsheni kunye umnqonqo, luyasekwa kakade phakathi Palsy. iinkqubo zabo obvorachivayut nezibaya zayo zangaphandle luvo plasmalemma kunye luvo kunye axons. Kubonakala ukuba myelin - kwezobom ubushushu zombane, delimiting iinkqubo zemithambo-luvo exutyiweyo.

iiseli Schwann kunye neempawu zazo

Le myelin esingxotyeni kwenkqubo luvo peripheral wambumba neyrolemmotsitami (iiseli Schwann). osemqoka yawo sikuko yokuba bangaba omnye kuphela esingxotyeni sokhuselo Umzobo wesi, kwaye azinako ukuba amahlumelo, njengoko sizalwa oligodendrocytes.

Phakathi kwiiseli Schwann kummandla 1-2 mm zibekwe iinxalenye akanayo myelin, ekuthiwa-njalo yindawo Ranvier. Ngokutsho kuye kwenzeka esithubeni Uhanjiso neemvakalelo zombane ngaphakathi Umzobo wesi.

Lemmotsity bakwazi ukulungisa le luvo, ngokunjalo enze umsebenzi trophic. Ngenxa aberrations yemfuza lemmotsitov Shell iiseli mitotic baqala kwisahlulo olungalawulwayo kunye nokukhula, apho ithumba kuphuhliswa kwiindawo ezahlukeneyo e-nervous system - schwannoma (neurinoma).

Indima microglia ekutshatyalalisweni kobume myelin

Microglia imele macrophage ezikwazi phagocytosis kwaye bakwazi ukuqaphela amasuntswana ezahlukeneyo yayintsholongwane eyosulela - ezisegazini. Ngenxa receptors inwebu, ezi seli glial ukuvelisa enzyme - proteases kunye cytokines, ezifana interleukin 1. Yena ungumlamleli nokudumba kunye nezifo.

Esingxobeni myelin, ogama umsebenzi kukuba ekwahluleni lombhobho yezihlunu kunye nokuphuculwa luvo ngokwentshukumisa seyonakele interleukin. Ngenxa yoko, i-luvo "ewuhlubile" kwaye isantya excitation lifinyele kakhulu.

Ngaphezu koko, cytokines, receptors isebenze bawaphikise ngokugqithisileyo zothutho ikhalsiyam ion kwi umzimba neuron. Protease kunye phospholipase baqala ninamathele organelles kunye neenkqubo iiseli zemithambo-luvo, nto leyo ekhokelela apoptosis - ukufa isakhiwo elinikiweyo.

Yena siyabutyaka, ukuqhekeza amasuntswana, leyo utshise macrophage. Le nto ibizwa ngokuba excitotoxicity. Oku bubangela ubani luvo kunye neziphelo zazo, nto leyo ekhokelela izifo ezifana Alzheimer kunye nesifo Parkinson kaThixo.

luvo Myelinated of

Ukuba iinkqubo neuronal - luvo kunye axons, nesigubungelo myelin esingxotyeni, zibizwa ngokuba myelinated kwaye innervate izihlunu skeletal, bangene ngokwahlulwa somatic kwenkqubo yoluvo luvo. imicu Unmyelinated enza le nkqubo yawo nervous kunye namaziko innervated.

iinkqubo Myelinated abe ubukhulu enkulu ngaphezu non-inyama, yaye kwasekwa ngolu hlobo lulandelayo: axons ukuyiphambukisa plasma inwebu iiseli glial kunye nefom yomgama mezaksony. Emva koko, ke ziyanatyiswa kunye neeseli Schwann azithandele ngokuphindaphindiweyo ehlabathini Umzobo wesi, ukwakha maleko concentric. Le kukho icytoplasm kunye kwahlelwa lemmotsita waya umaleko elingaphandle, leyo kuthiwa neurilemma okanye Schwann esingxotyeni.

Umaleko engaphakathi iquka mezoksona laminate lemmotsita ekuthiwa myelin esingxotyeni. balo babulingana nesandla kumacandelo ahlukeneyo luvo akufani.

Indlela ukubuyisela esingxotyeni salo myelin

Ukuqwalasela indima microglia e luvo demyelination, siye safumanisa ukuba phantsi isenzo macrophage kunye neurotransmitters (umz, neeinterleukins), ukutshabalala myelin, nto leyo yenza ukuba ukonakala kweendlela luvo zokuhambisa umbane kunye eyenza luvo kakuhle ecaleni Umzobo wesi.

Le ngezifo Uxhokonxwa iziphumo neurodegenerative: ukonakala kweenkqubo kwengqondo, ingakumbi inkumbulo kunye yokucinga, imbonakalo yokunqongophala kokuxhumana iintshukumo zomzimba kunye nezakhono motor entle.

Ngenxa yoko, ukukhubazeka kunokwenzeka epheleleyo yesigulane, nto leyo ngenxa yesifo samathambo. Ngoko ke umbuzo ukubuyisela njani myelin, okwangoku ingakumbi sibi. ndlela ziquka ikakhulu iproteni-lipid ukutya okunezondlo, ubomi rhoqo, ukungabikho nemikhwa emibi. Kwiimeko kakhulu, iyeza wasebenzisa izifo, ukunciphisa inani leeseli abaqolileyo glial - oligodendrocytes.