I myelin emgodleni we yezinzwa: umsebenzi wokutakula

Isimiso sezinzwa yomuntu ezilwaneni ezinomgogodla ezinamehlo unecebo olulodwa kwesakhiwo bewanikela isikhungo - the asebuchosheni nomgogodla, nezingxenye neuropathy - esukela emizimbeni lemcoka nezinzwa, amelela izinqubo ezinzwa - izinzwa.

isethi wabo amafomu izicubu kwemizwa, imisebenzi eyinhloko okuyinto excitability kanye conductivity. Lezi izindawo zichazwe ngaphezulu zonke izici isakhi ulwelwesi neuronal futhi ezihlobene zabo, ehlanganisa into okuthiwa myelin. Kulesi sihloko sizohlola indlela owakheke ngayo umsebenzi lo kwakwakhe, kanye ukuthola izindlela kungenzeka ukuthi ayibuyisele.

Kungani neurocytes nezinqubo imbozwe myelin

Akulona axons ukuqondana kwezinto kanye dendrites abe ungqimba zokuzivikela ehlanganisa lipid-amaprotheni izakhiwo. Iqiniso ukuthi isikhungo kuyinqubo biophysical, ogxile ababuthakathaka amaza kagesi. Lapho kagesi udabula wire, lona wamuva kumele embozwe nangokuvikela impahla ukunciphisa ukushabalalisa ka pulses kagesi kanye ukuvimbela ukwehla amperage. Imisebenzi ofanayo fiber ezinzwa idlulisa emgodleni myelin. Ngaphezu kwalokho, ukusekela, futhi inikeza ukudla fibre.

I chemical ukubunjwa myelin

Njengabantu abaningi cell ulwelwesi, it is a imvelo Esilula. Ngaphezu kwalokho, lokucuketfwe fat kakhulu - kufike ku-75%, namaprotheni - 25%. Myelin ngesilinganiso esincane futhi imbandakanya glycolipids futhi glycoproteins. Ukwakheka kwalo chemical ihlukile emizweni umgogodla futhi cranial.

Ekuqaleni kukhona wokuqukethwe lelisetulu phospholipids - kuze kufinyelele 45%, kanti bonke abanye livela cholesterol kanye cerebrosides. Demyelination (isb myelin indawo kwezinye izakhi ezikulesi ezinzwa izinqubo) kuholela izifo ezinzima ezifana sokuhlasela kwamasosha omzimba, njenge -multiple sclerosis.

Ngokombono amakhemikhali buka, Kwakuthatha libukeke kanje: emgodleni myelin ka yezinzwa ekushintsheni isimo sawo, okuyinto ngokuyinhloko ebonakaliswa ukwehla iphesenti lokuqukethwe lipid maqondana amaprotheni. Ngaphezu kwalokho ukunciphisa inani cholesterol bese ukhulisa okuqukethwe amanzi. Futhi konke lokhu kuholela esikhundleni kancane kancane myelin equkethe oligodendrocytes noma Schwann amaseli macrophage, astrocytes ne liquid intercellular.

Umphumela walezi zinguquko kwamakhemikhali kuyoba ukwehla elibukhali ikhono axons ukuqhuba ukuyaluza kuze Ukuvinjwa oluphelele ukudlula emsipheni amaza.

Izici amaseli neuroglial

Njengoba sekushiwo, kwakheka emgodleni myelin ka axons futhi dendrites is nge izakhiwo ezikhethekile, elinesimo degree eliphansi permeability ngoba sodium ne-calcium-ion, futhi ngenxa yalokho ukuba nekhono kuphela uhlezi (abakwazi ukuqhuba ezinzwa amaza futhi usebenze umsebenzi kagesi).

Lezi zakhiwo zibizwa ngokuthi amaseli glial. Lezi zihlanganisa:

• oligodendrocytes;
• astrocytes fibrous;
• amaseli ependymal;
• plasma astrocytes.

Bonke akhiwa olwelwesini umbungu - lo yi-ectoderm futhi abe negama ezivamile - macroglia. Glia nezinzwa onozwela parasympathetic futhi ukuphathwa kwabathintwayo emelelwa Schwann amaseli (neyrolemmotsitami).

Sakhiwo umsebenzi oligodendrocytes

Bayingxenye isimiso sezinzwa esiyinhloko futhi amaseli macroglia. Njengoba myelin - isakhiwo amaprotheni-lipid, ke kwandisa izinga excitation. Amaseli ngokwabo yakha isendlalelo kagesi nangokuvikela ka kwalapho kuhlangana khona imizwa asebuchosheni nomgogodla, siyaqoqwa kakade phakathi kwengane esiswini. izinqubo zabo obvorachivayut e emphethweni walo elingaphandle plasmalemma sezinzwa dendrites futhi axons. It kuvela ukuthi myelin - eyisisekelo kagesi ekuvikeleni impahla, delimiting izinqubo emsipheni we izinzwa okuxubile.

Schwann amaseli nezici zabo

Emgodleni myelin we-peripheral izinzwa uhlelo kwakhiwa neyrolemmotsitami (Schwann amaseli). sici yabo ehlukile liqukethe yokuthi bangakwazi ukwakha eyodwa kuphela emgodleni ayisivikelo Axon, futhi awukwazi ukwakha amahlumela, njengoba esivela oligodendrocytes.

Phakathi Schwann amaseli esifundeni 1-2 mm ezibekwe izingxenye elingenalo myelin, okuthiwa ISIZINDA ka Ranvier. Ngokusho kwakhe isigubhukane kwenzeka conduction ka amaza kagesi ngaphakathi Axon.

Lemmotsity ukwazi ukulungisa izinzwa, kanye enze umsebenzi trophic. Ngenxa aberrations zofuzo lemmotsitov igobolondo amaseli mitotic uqale division engalawuliwe nokukhula, lapho isimila athuthukile ezingxenyeni ezahlukene isimiso sezinzwa - schwannoma (neurinoma).

Indima microglia ekubhubhiseni myelin isakhiwo

Microglia limelela macrophage uyakwazi phagocytosis futhi bakwazi ukuqaphela izinhlayiya ezahlukene pathogenic - antigen. Ngenxa receptor ulwelwesi, la mangqamuzana glial ukukhiqiza enzyme - proteases futhi cytokines, ezifana interleukin 1. umlamuleli ukuvuvukala nokuvikeleka.

Emgodleni myelin, ogama umsebenzi ukuhlukanisa uMbhalo Axial nokwenziwa ngcono emsipheni ngiyibona seyonakele interleukin. Ngenxa yalokho, emsipheni "dalulwa" futhi ijubane excitation is kakhulu ziyancipha.

Ngaphezu kwalokho, cytokines, receptor isebenze avuse ngokweqile-calcium ion ezokuthutha zibe umzimba namangqamuzana ezinzwa. Ama-protease bese phospholipase uqale ninamathele organelles netinchubo ezinzwa, okuholela apoptosis - kokufa isakhiwo inikezwe.

Yena ehlala, ukugqekeza izinhlayiya, okuyinto ashwabadele macrophage. Lesi senzakalo ngokuthi excitotoxicity. Kubangela ukonakala sezinzwa eziyimpumelelo zabo, okuholela izifo ezifana Alzheimer futhi Parkinson.

yezinzwa Myelinated ka

Uma izinqubo neuronal - dendrites futhi axons, isembozo myelin emgodleni, bebizwa myelinated futhi innervate imisipha lwamathambo, ngokufaka division ukuphathwa kwabathintwayo we-peripheral nervous system. Imicu yotshani Unmyelinated yakha autonomic nervous system kanye nezinhlaka innervated.

izinqubo Myelinated abe ubukhulu kunenani okungezona esinamanzi, futhi akhiwa kanje: axons azingenwa ulwelwesi plasma lamaseli glial futhi ifomu komugqa mezaksony. Khona-ke, basuke enwetshiwe futhi Schwann amaseli ngokuphindaphindiwe ezizungeze Axon, ukwakha izingqimba eyindilinga. I cytoplasm futhi nucleus lemmotsita iyiswe olwelwesini ebizwe neurilemma noma Schwann emgodleni.

Isendlalelo kwangaphakathi siqukethe mezoksona laminate lemmotsita ngokuthi myelin emgodleni. Uhlonze lwalo ezigabeni ezahlukene emsipheni akufani.

Indlela ukubuyisela emgodleni myelin

Uma ucabangela indima microglia e emsipheni demyelination, sathola ukuthi ngaphansi isenzo macrophage kanye neurotransmitters (isib interleukin), ukubhujiswa myelin, okuyinto ke kuholela Ukuwohloka izinzwa amandla ukuwudlulisa kahle ezinzwa amaza eduze Axon.

Lokhu zokugula kuphakamisa imiphumela neurodegenerative: Ukuwohloka izinqubo engqondweni yethu, ikakhulukazi inkumbulo futhi ukucabanga, ukubukeka Ukungabibikho kokuxhumana komzimba futhi emihle motor amakhono.

Ngenxa yalokho, kungenzeka ukukhubazeka egcwele isiguli, okuyinto umphumela isifo sokuhlasela kwamasosha omzimba. Ngakho umbuzo kanjani ukubuyisela myelin, okwamanje acute ikakhulukazi. izindlela ezinjalo zihlanganisa ngokuyinhloko ukudla okunempilo amaprotheni-lipid, ukuphila njalo, ukungabi khona imikhuba emibi. Ezimweni ezimbi kakhulu, imithi isetshenziswa izifo, ukunciphisa inani lamaseli ovuthiwe glial - oligodendrocytes.