CNS sakhiwo. luvo ifayibha

Nerve ifayibha izalelwe yinto neuron, lisesingxobeni glial isale. Kutheni kuyimfuneko? Ntoni? Yintoni na isakhiwo? Oku uya ukufunda eli nqaku.

ngezigaba

Imicu -luvo kufuneka isakhiwo eyahlukileyo. Ngokuhambelana kunye nesakhiwo babe omnye kweentlobo ezimbini. Ngenxa yoko, imicu ekwanti unmyelinated kunye myelinated. Eyokuqala ibandakanya inkqubo iseli, nto leyo ibekwe esizikithini isakhiwo. Ibizwa i Umzobo wesi (axons). Le nkqubo singqongwe esingxotyeni salo myelin. Ngenxa yobume ngobunzulu umthwalo esebenza, ukuyilwa luvo sohlobo elinikiweyo. Ubume bale izakhiwo ixhomekeke isebe apho ibekwe. Umzekelo, apho isebe kwinkqubo somatic luvo amalungiselelo luvo myelinated, kunye kwezityalo - unmyelinated. Kufuneka ke ukuba ukuyilwa ezi kunye nezinye zitraksha zilandelayo ngendlela efanayo.

Njengoko kukho luvo ifayibha obhityileyo?

Qwalasela inkqubo zolwimi ngokunzulu. Xa ixesha ukuyilwa kwezakhiwo ezifana Umzobo wesi unmyelinated delves kulo mngxilo equlathe lemmotsitov ngubani tsitolemmy aqale ehle ugqume inkqubo kumgaqo kokubonisa. Edge kule wasondela le Umzobo wesi, uMbumbi duplikatury le inwebu yeseli, leyo ibizwa ngokuba "mezakson". Lemmotsity, ibekwe ucango elandelayo, senziwa ngoncedo tsitolemmy nabo abo elula. imicu Unmyelinated ngenxa yokugquma amahlwempu esikwaziyo abapasa i-luvo ngokwentshukumisa indawo kunye mezaksona kunye nakummandla lokudibana phakathi lemmotsitami. Ngenxa yoko, udlula ukusuka kwenye ifayibha ukuya kwenye.

Formation kwezakhiwo zamafu

Nerve ifayibha myelin kakhulu ziyatyeba uhlobo unmyelinated. Ngokutsho inkqubo yokutshata amaqokobhe ziyafana. Noko ke, ukukhula okwandisiweyo luvo kwisebe somatic, nto leyo ehambisana kunye nophuhliso umzimba uphela, ekhuthaza elula mezaksonov. Emva koko lemmotsity lwemigca axons izihlandlo eziliqela. Ngenxa yoko, ezi zoleko concentric akhiwa uhlobo, kwaye engundoqo ningashukunyiswa nimke kukho icytoplasm ukuya coil wokugqibela, nto leyo ke esingxotyeni engaphandle ifayibha (neurilemma). Umaleko engaphakathi ibandakanya mezaksona, entwined ngokuphindaphindiweyo ngokuba myelin. Ekuhambeni kwexesha, inani amathuba kunye nemilinganiselo mezaksona chu kunyuka. Oku kungenxa wawo ukuya kuvala ingxingwa inkqubo myelination ngexesha lokukhula axonal kunye lemmotsitov. ithuba ngalinye elandelayo olubanzi yangaphambili. Uqeqesho olubanzi kakhulu nguye equlathe kukho icytoplasm ukuya lemmotsita ngumongo. Ngapha koko, ubukhulu myelin ezahlukeneyo kwaye kulo lonke ubude ifayibha. Kwezo ndawo apho lemmotsity ukunxibelelana nabanye, lo ezithile ngokwezinga shwaka. Le umfowunelwa kungena kuphela maleko bangaphandle, eziquka kukho icytoplasm kunye isiqalo. sites ezinjalo akhiwa ngenxa yokusilela kwabo myelin ukuxozwa ifayibha kunye namagama host maziko.

Ukukhula kwezakhiwo kwinkqubo luvo

Myelination kwenzeka kule nkqubo ngenxa yeenkqubo ze axons oligodendrocytes urhangqo. Myelin yi isiseko lipid kwaye ngentsebenziswano kunye oxides ufumana mnyama. Amacandelo abasele inwebu kunye interstices ayo ahlale ukukhanya. Ezi iziqwenga ibizwa ngokuba iinotshi okwenzekayo myelin. Ziyangqinelana iyaxela elincinane lemmotsita kukho icytoplasm. A Umzobo wesi kwi icytoplasm kunye mitochondria neurofibrils ahlelwe longitudinally. Inani labo kakhulu - kufutshane ukuvimbela kwi imicu izixhobo ekupheleni. Tsitolemmy Umzobo wesi (axolemma) ikhuthaza nemithambo uyibona. Kubonisa wave kwayo depolarization. Kwimeko apho njengoko itankana neurite yezihlunu thaca, iqulethe granules basophilic kweziyobisi.

isakhiwo

luvo Myelinated lubandakanya:

1. Umzobo wesi, nto leyo ibekwe embindini.
2. esingxotyeni Myelin. Le igutyungelwe esqwini njengesilinda.
3. Schwann shell.

Langoku composition neurofibrils isilinda yezihlunu. Esingxotyeni salo myelin sakhiwa nobuninzi kwezinto lipoid wokusungula myelin. Le uxhulumaniso ubaluleke kakhulu kwinkqubo luvo. Ngokukodwa, eyikhethayo isantya apho Uhanjiso of excitation e-luvo. Iqokobhe kwakhiwa compound Umzobo wesi luvalwa ukuze izikhewu kwakheka, ezo zibizwa ngokuba yindawo Ranvier. Kwindawo kwabo ukunxibelelana lombhobho ezimanyeneyo Schwann esingxobeni. ifayibha ingxenye - gap yayo, ephakathi kwiindawo ezimbini Ranvier. Kokuba kube nokuqwalaselwa nengundoqo we-Schwann esingxobeni. Le ebekwe malunga kwi ingxenye embindini. Oku engqongwe ngabantu protoplasm weseli Schwann okubhalwe myelin kwi semigaqo. In phakathi yindawo Ranvier myelin esingxobeni ayikho eyohlobo olulodwa. Iqulethe zingakhona elibhalwe ngokumileyo Schmidt-Lanterman. Schwann cell inwebu ziqala ukukhula ukusuka ectoderm. Ngezantsi kuzo i Imicu Umzobo wesi kwenkqubo peripheral luvo, apho baya kubizwa kwayo iiseli glial. luvo kwinkqubo ephakathi lube Schwann iqokobhe. Endaweni yoko, kukho izinto oligodendroglial. ifayibha Unmyelinated iye axons kuphela kunye esingxotyeni Schwann kumafa yayo.

umsebenzi

Lo msebenzi ephambili eyenziwa yi ifayibha luvo - innervation. Le nkqubo kweentlobo ezimbini: ukubetha kwentliziyo bezimpulsnym. Kwimeko yokuqala, ukosuleleka kwenzeka ngokusebenzisa electrolyte kunye neurotransmitter iindlela. Le innervation inendima enkulu indima myelin, ngoko ke isantya inkqubo iphezulu kakhulu kwi kwimicu myelinated kunokuba unmyelinated. Inkqubo bezimpulsnogo uhlobo kwenzeka axoplasm yangoku ehamba microtubules ezikhethekileyo axonal, eziquka trofogeny (izinto ezinempembelelo trophic).