Galkeeda myelin The macdantaa dareemayaasha: kabashada shaqada

habka dareemayaasha jirka Aadanaha oo vertebrates qorshe hal dhisme ah oo lagu soo bandhigay xarunta - maskaxda iyo laf-dhabarta, iyo qaybo ka durugsan - neurons - ka meydadka dhexe ee dareemayaasha, kaas oo wakiil geedi socodka of unugyada dareenka kordhin.

Foomamka set ay unugyada neural, hawlaha ugu muhiimsan ee taas waa excitability iyo conductivity. guryaha Kuwan waxaa u sharaxay oo dhan muuqaalada dhismaha xuubka neuronal iyo appendages ay kor, oo ka kooban myelin walax loo yaqaan. In this article waxaan eegi doonaa qaabka iyo shaqada xarunta this, iyo sidoo kale aad u ogaato siyaabood ee suurtagal ah si ay u soo celiyaan.

Maxaad neurocytes iyo geedi socodka daboolay by myelin

Waa ma Axon kadis iyo dendrites leeyihiin lakabka ilaaliya oo ka kooban kaxeynayo la egyahay-protein. Xaqiiqada ah in hay'adda waa hab biophysical, kaas oo ku salaysan u dhaqdhaqaaqa korontada daciif ah. Marka hadda korontada maraa silig, dambaysta ah waa in la daboolay qalabada wax si loo yareeyo dhereg badan ee la karsado korontada iyo si looga hortago in hoos u dhac ku amperage. Shaqooyinka isla fiber dareemaha xanbaarsan galkeeda myelin ah. Intaas waxaa sii dheer, waa taageero, iyo sidoo kale cunto siisaa fiber a.

Walxaha kiimikada ee myelin

Like xuubka unug ugu, waa dabeecadda lipoprotein ah. Waxaa intaa dheer, content baruurta waa mid aad u sarreeya - ilaa 75%, iyo protein - 25%. Myelin in tiro yar ayaa sidoo kale ka kooban yahay glycolipids iyo glycoproteins. Its Halabuurka kiimikada waa kala duwan ee dareemayaasha spinal iyo cranial.

Marka ugu horeysa waxaa jira content sare ah phospholipids - ilaa 45%, iyo inta kale ee ka timaada kolestaroolka iyo cerebrosides. Demyelination (i.e. bedelka myelin for walxaha kale ee hababka dareemayaasha) keenaysaa in shalalka daran sida, sida sclerosis.

Laga soo bilaabo dhibic kiimikada ee view, habkan u ekaan kartaa sidan: galkeeda myelin macdantaa dareemaha beddelo qaab-dhismeedkeeda, kaas oo ugu horayn muujiyey in hoos u dhac in boqolkiiba content la egyahay ee la xiriirta borotiinada. Dheeraad ah oo ku hoos lacagta oo kolestarool ah iyo kor u kacay content biyaha. Oo waxaas oo dhan waxay keenaysaa in bedelka tartiib ah myelin kooban oligodendrocytes ama unugyada Schwann on macrophages, astrocytes iyo dareere intercellular.

Natiijadan ayaa ka mid ah isbedel lagmamaarmaanna u noqon doono hoos u dhac af ee awoodda Axon si ay u qabtaan cadhoodaan ilaa ku furid dhamaystiran oo marinka ee falalkooda dareemayaasha.

Features unugyada neuroglial

Sida hore u soo sheegnay, galkeeda myelin ee Axon iyo dendrites waxaa la aasaasay la dhismeedka gaarka ah, lagu gartaa heerka hoose ee permeability for sodium iyo calcium udhigo, oo sidaas daraaddeed isagoo kara oo kaliya nasasiiyay (ma ay qaban karaan falalkooda dareemayaasha iyo shaqeeyaan shaqada korontada).

qaababka waxaa lagu magacaabaa unugyada glial. Kuwaas waxaa ka mid ah:

• oligodendrocytes,
• astrocytes buunshada ku,
• unugyada ependymal;
• astrocytes plasma.

Oo kulligoodna waxaa lagu soo sameeyey lakabka sare ee embriyaha - ectoderm ah oo ay leeyihiin magac caadi ah - macroglia. Glia dareemayaasha dabacsanaadaan, parasympathetic iyo degaaankaaga wakiil Schwann unugyada (neyrolemmotsitami).

Dhismaha iyo shaqada oligodendrocytes

Waxay qayb ka mid ah habka dhexe ee neerfayaasha yihiin oo waa unugyo macroglia. Tan iyo myelin - dhismeedka protein-egyahay a, u kordhiyaa heerka of excitation. isu unugyada sameeyaan lakabka ah koronto qalabada of dhammaato dareemeyaasha ee maskaxda iyo xangulada, la horey u sameeyay inta lagu guda jiro horumarinta uurjiifka. hababka ay obvorachivayut in laalaabka ay dibadda ee neurons plasmalemma iyo dendrites iyo Axon. Waxaa soo baxday in myelin ah - wax qalabada korontada aasaasiga ah, la xadeeyo hababka dareemayaasha ee dareemayaasha isku qasnaa oo.

unugyada Schwann iyo qaababka ay

galkeeda myelin nidaamka neerfaha durugsan sameeyay neyrolemmotsitami (unugyada Schwann). Ay feature kala ka kooban yahay in xaqiiqda ah in ay abuuri karaan oo keliya hal galkeeda ka nabadgeli axon ah, oo aan sameysmi karaa caleemaha, sida ay tahay dhaxal oligodendrocytes.

Inta u dhaxaysa unugyada Schwann ee gobolka of 1-2 mm waxaa la geeyaa qaybo ka maran myelin, qanjidhada ee Ranvier-ka loo yaqaan. Sida laga soo xigtay isaga si ay u jir- dhacdaa tabinta ah falalkooda korontada gudahood axon ah.

Lemmotsity awoodaan si ay u cusboonaysiiyaan fiiloyin dareemaha, iyo sidoo kale qabtaan shaqo trophic. Sidaas darteed of aberrations hidde lemmotsitov madaafiic unugyada mitotic bilaabaan inay kala qeybinta caasiyoobay iyo koritaanka, dheehan burada horumariyo qaybaha kala duwan ee habka dareemayaasha - schwannoma (neurinoma).

Doorka microglia in burburinta dhismeedka myelin

Microglia ka dhigan macrophages awood phagocytosis iyo awoodaan in ay aqoonsadaan qayb pathogenic kala duwan - cudur. Thanks to receptors xuub, kuwaas unugyada glial soo saaro ensaymes - proteases iyo cytokines, sida interleukin 1. Waxa uu u yahay dhexdhexaadiyaha ah barar iyo difaac.

galkeeda myelin The, kuwaas oo shaqada waa in la go'doomiyo dhululubo ee axial iyo horumarinta Suu dareemayaasha dhaawac laga yaabaa interleukin. Sidaas darteed, dareemaha "dhigay dhashay" iyo xawaaraha excitation waxaa si weyn u dhimay.

Waxaa intaa dheer, cytokines, receptors kaakicin cadhaysiinina gaadiidka calcium ra'iyi xad-dhaaf ah u galay jidhka neuron ah. Protease iyo phospholipase bilaabaan inay ku hadhaan organelles iyo geedi socodka ka mid ah unugyada dareenka, taas oo horseedaysa apoptosis - dhimashada dhisme siiyey.

Waxay burburo, jebinta galay Qurub, oo wuxuu wada laasan macrophages. Tani waxay ifafaale waxaa lagu magacaabaa excitotoxicity. Waxay keentaa xumaanshaha ee neurons iyo dhammaato ay, taasoo keentay in cudurada sida Alzheimers iyo cudurka Parkinson.

Dunta dareemayaasha Myelinated ah

Haddii geeddi neuronal - dendrites iyo Axon, iyo dedkeeda galkeeda myelin ah, waxaa loo yaqaannaa myelinated iyo innervate murqaha lafaha, galaya horyaalka degaaankaaga of habdhiska ka durugsan. Dunta Unmyelinated sameeyaan nidaamka autonomic neerfayaasha iyo xubnaha innervated.

geeddi socodka Myelinated leeyihiin ballaciisu yahay ka badan aan la fareeshka ah, oo loo sameeyay sida soo socota: Axon leexiyo xuub plasma unugyada glial iyo mezaksony qaab toosan ee. Markaas, waxay kordhin iyo unugyada Schwann joogta ah ku duub agagaarka axon ah, la xirrira layers-gashan. cytoplasm iyo xuduntii lemmotsita ayaa u dhaqaaqay daaha dibadda, oo la yidhaahdo neurilemma ama galkeeda Schwann.

Lakabka hoose wuxuu ka kooban yahay mezoksona lemmotsita laminate ah oo lagu magacaabo galkeeda myelin. oo dhumucdiisuna waxay in qaybaha kala duwan ee dareemaha ma aha isku mid.

Sida loo soo celiyo galkeeda myelin ah

Fiirsaneysa inay doorka microglia in demyelination dareemayaasha, waxaan ka helay in ka yar tallaabada of macrophages iyo neurotransmitters (tus, interleukins), waa u baabba 'myelin, taas oo keenta inay ka sii darto oo ka mid ah neurons gudbinta xoog iyo falalkooda dareemayaasha oo yaraada weheliyaan axon ah.

cudurada Tani dhirfinaya saamaynta neurodegenerative: daraysa ee geedi socodka garashada, gaar ahaan xusuusta iyo fikirka, muuqaalka kore ee la'aan isuduwidda dhaqdhaqaaqa jidhka iyo xirfadaha dhaq ganaax.

Sidaas darteed, naafada buuxa suurto galka ah ee bukaan-socodka, taasoo ah natiijada cudur, shalalka. Haddaba su'aashu waxay of sida loo soo celin myelin, haatan waxa ay si gaar ba'an. Hababka noocan oo kale ah waxaa ka mid ah ugu horayn cunto isku dheeli tiran protein-la egyahay, nolosha caadiga ah, maqnaanshaha of caadooyinka xun. Xaaladaha daran, daawada loo isticmaalo cudurada, yaraynta tirada unugyada glial baaluq - oligodendrocytes.