Schwann hlwb (lwm yam myelocytes lossis neurolemmocytes) xa mus rau cov neuroglia ntawm lub paj hlwb peripheral, qhov uas lawv nrog cov txheej txheem ntev ntawm cov neurons ua cov khoom pabcuam. Hauv cov ntsiab lus ua haujlwm, lawv yog cov analogues ntawm oligodendrocytes tam sim no hauv CNS. Schwann hlwb nyob ze axons, tsim sheaths ntawm peripheral hlab ntsha txoj kev.
Myelocytes tau tshwm sim thawj zaug hauv xyoo 1838 los ntawm German kws kho mob Schwann, tom qab uas lawv tau hu ua.
yam ntxwv dav dav
Nrog rau mantle gliocytes, lemmocytes yog cov ntsiab lus tseem ceeb ntawm peripheral glia thiab zoo ib yam li oligodendrocytes nrog axons. Txawm li cas los xij, tseem muaj qee qhov sib txawv ntawm lawv - feem ntau nyob rau hauv qhov chaw Schwann hlwb nyob. Cov tom kawg nrog cov fibers ntawm PNS, thiab oligodendrocytes muaj nyob rau hauv grey thiab dawb teeb meem ntawm lub hauv paus paj hlwb. Txawm li cas los xij, hauv qee qhov kev faib tawm, peripheral glial hlwb raug suav hais tias yog ntau yamoligodendroglia.
Qhov txawv ntawm Schwann hlwb kuj yog tias lawv tsuas yog npog ib qho axon, thiab oligodendrocyte - ob peb zaug ib zaug. Raws li hom sheath tsim, neurolemmocytes yog ob hom - myelinated thiab non-myelinated, uas tsim peripheral fibers ntawm cov khoom sib xws.
Myelocytes nyob rau ntawm lub tog raj kheej ua haujlwm. Schwann hlwb zoo li braid cov fiber, tsim cov ntu ntu, nruab nrab ntawm cov nodes ntawm Ranvier.
Lub tsev nta
Cov yam ntxwv cytological ntawm lemmocytes suav nrog:
- poorly qhia cov khoom siv hluavtaws (EPS thiab lamellar complex);
- poorly tsim mitochondria;
- dub xim kernels.
Qhov ntev ntawm Schwann tawb txawv ntawm 0.3 txog 1.5 mm.
Functions
Schwann hlwb ua lub luag haujlwm pabcuam hauv kev tswj xyuas cov haujlwm ntawm cov paj hlwb. Tib lub sijhawm, lawv ua 5 lub luag haujlwm tseem ceeb:
- txhawb - lub network ntawm lemmocytes tsim cov qauv txhawb nqa rau cov neurons thiab lawv cov txheej txheem;
- trophic - ntau yam khoom noj los ntawm lemmocytes rau cov txheej txheem;
- regenerative - lemmocytes koom nrog hauv kev kho cov paj hlwb puas;
- tiv thaiv - cov txheej txheem neural tsim nyob ib ncig ntawm lub tog raj kheej axial muab kev tiv thaiv ntxiv rau kev puas tsuaj;
- insulating (tsuas yog rau myelinated fibers) -- myelin txheej tiv thaiv tawmhluav taws xob teeb liab sab nraud ntawm cov hlab ntsha tshwj xeeb.
Schwann hlwb ua lub luag haujlwm loj hauv kev kho cov paj hlwb puas. Thaum ib qho axon ruptures, lemmocytes thawj phagocytize cov khoom puas, thiab tom qab ntawd muab faib ua tus choj txuas cov txheej txheem uas nyob ib sab. Tom qab ntawd ib lub tog raj kheej axial tau tsim dua hauv cov channel no.
