Maumbirwo uye Mashandiro eSchwann Cells
Masero eSchwann imhando yemasero eglial (sero rinotsigira) anowanikwa mu peripheral nervous system (PNS). Basa rawo guru rakakosha nekuti ndiwo anokonzera kuumbwa kwemyelin, kudzivirira axon, uye kubatsira mukugadzirisa tsinga mushure mekukuvara. Pasina masero eSchwann, tsinga dzinofamba hadzigone kufamba zvakanaka uye nekukurumidza sezvinoda muviri kuti urongedze kufamba, kunzwa, uye mabasa akasiyana-siyana enhengo. Chinyorwa chino chinokurukura chimiro chemasero eSchwann, mashandiro awo, uye mabasa akakosha anoita kuti ave akakosha kuhutano hwetsinga.
Tsanangudzo uye chinzvimbo chemasero eSchwann muhurongwa hwetsinga
Muhurongwa hwetsinga, masero eglial anoshanda se "chikwata chekutsigira" masero etsinga. Muhurongwa hwetsinga hwepakati (CNS), senge uropi nemuzongoza, myelin inoumbwa nemaoligodendrocytes. Panguva imwecheteyo, muhurongwa hwetsinga hweperipheral, basa iri rinowira kumasero eSchwann. Masero eSchwann anonamatira kuma neuronal axons uye, kuburikidza nemaitiro chaiwo, anoafukidza, achiumba jira remyelin kana imwe sheath inodzivirira, zvichienderana nerudzi rweaxon yaanoshanda.
Masero eSchwann anogona kuwanikwa mutsinga dzese dzemuviri, kusanganisira tsinga dzinonzwa (dzinotakura ruzivo kubva kumareceptor kuenda kuuropi), tsinga dzinofambisa mweya (dzinotakura mirairo kubva kuuropi kuenda kutsandanyama), uye tsinga dzinozvitonga (dzinodzora nhengo dzemukati pasina kuziva).
Maumbirwo emasero eSchwann
Kazhinji, masero eSchwann ane chimiro chakagadzirirwa basa rawo sechifukidziro uye rutsigiro rweaxons. Zvimwe zvezvinhu zvakakosha zvinosanganisira:
1. Muviri wesero nepfungwa yesero
Masero eSchwann ane manyuchi anowanzo kuwanikwa pamucheto wesero, kunyanya kana sero richigadzira myelin. Iyi nzvimbo ye "peripheral" yenucleus ine chekuita nemakoiri akawanda e myelin-forming membrane coils mune dzimwe nzvimbo.
2. Kamudzira keplasma kakakomberedza axon
Hunhu hukuru hwemasero eSchwann kugona kwawo kutenderedza maaxon. Plasma membrane yavo inotenderedza axon kakawanda kuti igadzire layer ine zvidimbu zvakawanda, ine lipid yakawanda. Layer iyi inonzi myelin sheath, iyo inoshanda se electrical insulator.
3. Cytoskeleton nezvikamu zvemukati
Kufanana nemamwe masero, masero eSchwann ane cytoplasm ine organelles (mitochondria, endoplasmic reticulum, Golgi apparatus) kuti agadzire simba uye adzore kugadzirwa kwemapuroteni. Mamwe mapuroteni akakosha kuti myelin igadzikane uye kuti ataurirane neaxons.
4. Basal lamina (basal lamina)
Chimwe chinhu chakakosha pamasero eSchwann kuvapo kwebasal lamina yakakomberedza masero. Rutivi urwu runobatsira pakutsigira chimiro chemasero, runopa kubatana kwemasero, uye rwakakosha pakuvandudza tsinga mushure mekukuvara. Basal lamina inogona kushanda se "rail" kana nzira, ichibatsira axon kukura zvakare.
Mhando dzemasero eSchwann zvichienderana nebasa rawo
Masero eSchwann haawanzogadzira myelin. Kune mapoka maviri makuru:
1. Masero eSchwann anogadzira myelinating (masero eSchwann anogadzira myelinating)
Myelin yesero rimwe chete reSchwann inowanzo tenderedza chikamu chimwe chete cheaxon. Kupatsanurwa uku kunoita kuti pave nemikana midiki pakati pema myelin sheaths anonzi ma nodes eRanvier. Ma nodes eRanvier akakosha pakufambisa nekukurumidza kwema impulses kuburikidza ne saltatory conduction (impulses "jumping" kubva pane rimwe node kuenda kune rinotevera).
2. Masero eSchwann asingaburitse myelin (masero eSchwann asingaburitse myelin)
Muma axon madiki-diki, masero eSchwann haagadzire myelin yakakora, asi panzvimbo pezvo anounganidza ma axon akati wandei pamwe chete mu "mabundle" anonzi Remak bundles. Kunyangwe asina myelin, masero eSchwann achiri kupa rutsigiro nedziviriro yemetabolism.
Maumbirwo eMyelin uye ma nodes eRanvier
Mutsipa wemyelin unoumbwa nechikamu chemembrane chine lipid-rich, zvichiita kuti chive insulator. Chikamu ichi chinoderedza kubuda kwemagetsi kubva mu axon uye chinokurumidza kutapurirana kwesimba rekuita. Mutsinga dzine myelin, impulses hadzifambi nguva dzose, asi "dzinosvetuka" pakati pema nodes eRanvier. Kufambisa kwemunyu uku kunokurumidza uye kunoshandisa simba zvakanyanya kupfuura kufamba nechikamu chose che axon.
Pamusoro pezvo, kune nzvimbo dzakagadzirwa pa axon iri pedyo ne node, dzakadai se paranode ne juxtaparanode, idzo dzine mapuroteni akawanda eion channel uye mapuroteni e adhesion. Masero eSchwann anoita basa rekuchengetedza kurongeka uku kwe microstructural kuchengetedza zviratidzo zvetsinga zvakagadzikana.
Basa guru remasero eSchwann
1. Inogadzira myelin uye inokurumidza kutumira kwemhepo
Basa rayo rinozivikanwa zvikuru kuumbwa kwe myelin sheaths patsinga dzeropa. Myelin inowedzera nekukurumidza kufambiswa kwemhepo. Izvi zvinobvumira mhinduro dzemotokari nekukurumidza uye nemazvo (semuenzaniso, kudzosa ruoko kana rwaiswa pakupisa) uye kugadziriswa kwemanzwiro (kunzwa kubatwa zvishoma).
2. Kuparadzanisa nekudzivirira ma axon
Myelin inoshanda semudziyo wemagetsi, ukuwo masero eSchwann anowanzo dzivirirawo maaxon mumuviri. Dziviriro iyi inoita kuti maaxon arambe achidzivirira kukanganiswa munzvimbo dzakatenderedza nyama.
3. Rutsigiro rwema metabolic neurons
MaNeuron anoda simba rakawanda, uye maaxon anogona kureba zvikuru. Masero eSchwann anobatsira kuona kuti maaxon anowana rutsigiro rwemetabolism kuburikidza nekuchinjana kwezvinovaka muviri uye masaini emamorekuru. Basa iri rakakosha pakurarama kwenguva refu kwekushanda kweaxon.
4. Kuvandudzwa kwetsinga mushure mekukuvara
Chimwe chezvakanakira zve peripheral nervous system kupfuura central nervous system ndechekuti ine kugona kukuru kwekuvandudza mashandiro ayo. Masero eSchwann anoita basa guru mukuita uku kuburikidza nematanho akati wandei:
– Kupatsanurwa uye kuwanda kwemasero: mushure mekukuvara, masero eSchwann akakomberedza nzvimbo yakakuvara anoshanduka kuita chimiro chinotsigira kugadziriswa, obva awanda.
– Kuchenesa marara e myelin: Masero eSchwann anoshanda nemacrophages kuchenesa marara e myelin anogona kudzivirira kugadzikazve kwemasero.
– Kugadzira “Mabhendi eBüngner”: Masero eSchwann anozvironga kuti agadzire nzira inotungamira kukurazve kwemaaxons kuenda kunzvimbo dzaanoda.
– Zvinobudisa tsinga dzinokura: Masero eSchwann anogadzira mamorekuru akadai se neurotrophins nezvimwe zvinhu zvinokura zvinokurudzira axon elongation.
Pasina rutsigiro rwemasero eSchwann, kugadzurwa kweaxon muPNS kwaizononoka uye kwaisazotungamira zvakanyanya.
5. Inodzora kukura kwetsinga uye kukura kwetsinga
Masero eSchwann akakoshawo kubva pakukura kwemwana ari mudumbu kusvika pakukura. Anobatsira kukura kwetsinga dzeropa, kuona kuti ndeapi ma axon achaiswa myelinated, uye kugadzirisa ukobvu hwe myelin zvichienderana nehukuru hwe axon. Hukama uhwu hunoshanduka-shanduka: ma axon anotumira zviratidzo kumasero eSchwann, uye masero eSchwann anopa mhinduro inokanganisa kugadzikana kwe axon uye mashandiro ayo.
6. Basa guru mukudzivirira muviri uye kuzvimba kwemuviri
Mune mamwe mamiriro ezvinhu, masero eSchwann anogona kuita basa guru mukupindura kwemasoja emuviri munharaunda. Anogona kugadzira mamorekuru anoburitsa zviratidzo zvinounganidza masero emasoja emuviri kana kugadzirisa kuzvimba. Izvi zvakakosha kana tichitarisa kukuvara kwetsinga dzeropa nezvirwere.
Kukosha kwekiriniki: kana masero eSchwann akakanganisika
Kukuvara kana kusashanda zvakanaka kwemasero eSchwann kunogona kukonzera chirwere chepfungwa cheperipheral neuropathy. Semuenzaniso:
– Guillain-Barré syndrome (GBS): chirwere che autoimmune chinowanzo rwisa myelin muPNS, zvichikonzera kushaya simba kwetsandanyama uye kusagadzikana kwemanzwiro.
– Charcot–Marie–Tooth (CMT): boka rezvirwere zvemajini zvinogona kusanganisira kusashanda zvakanaka kwemasero eSchwann, zvichikonzera kushaya simba kwetsandanyama dzemudumbu uye kusagadzikana kwekufamba.
– Neuroma neschwannoma: bundu rinobva kumasero eSchwann, kazhinji harina njodzi asi rinogona kudzvanya tsinga uye kukonzera zviratidzo.
Kunzwisisa masero eSchwann kwakakosha pakutsvaga nzira dzekurapa tsinga itsva, mainjiniya ematishu, uye kugadzirwa kwemishonga yekubvisa myelin mumasero.
Mhedziso
Masero eSchwann zvinhu zvakakosha muhurongwa hwetsinga dzemudumbu. Muchimiro, masero aya ane kugona kwakasiyana kwekufukidza ma axon, kuumba myelin, uye kupa basal lamina, iyo inokosha pakugadzikana uye kudzoreredza. Mukushanda, masero eSchwann anokurumidza kufambiswa kwemhepo kuburikidza ne saltatory conduction, anodzivirira ma axon, anotsigira metabolism ye neuronal, anotonga kukura kwetsinga, uye anoita basa guru mukugadzirisa tsinga dzemudumbu mushure mekukuvara. Nekunzwisisa chimiro uye mashandiro emasero eSchwann, tinogona kunzwisisa zviri nani mashandiro anoita tsinga uye kuti nzira dzekurapa dzinogona kugadzirwa sei kugadzirisa matambudziko akasiyana-siyana etsinga dzemudumbu.
