MYELINATIONO F NEURONSO F THEG ENICULATEG ANGLIONIN GUINEAP IGS:A N ULTRA$TRUCTURASL TUDY IN THE PERINATALP ERIODA ND ADULTL IFE.

Document Type : Original Article

Authors

1 Departmentos f Anatomya nd E. N T. Ain Shams University

2 Departmentos f Anatomya nd E. N T. Ain Shams Universi

Abstract

The acousticofaciagla nglioni s mainlyd erivedf rom the neuralc rest,l t consistso f a vestibulocochleapra rtw hicha t firstf usedw itht he gangliono f the facial nerve but later,t he two separate.T he vestibulara nd cochlear gangliae ach becomesa ssociatedw ith the correspondindgi visiono f the eighthn erve.C ellso f the vestibulaar nd cochlearg angliar emainb ipolar
throughoulti fea nd theirn euronsa re unusuailn that manyo f theirs omata becomee nvelopedin thin myelins heaths( Williamse t al. 1995).M osto f the vestibulagr anglionn euronsa re surfoundedb y thin myelins heathi n humans( Ona and Kanzaki,1 99{),i n adults quirreml onkey( Fermina nd lgrashi,1 982),i n cat( $pasova,1 982),i n rabbitsa nd in bats( Ona,1 993). Ultrastructurafel atureso f the human spiral (cochlear)g anglionr evealedt hat large myelinatedn euronsw ere few. However,t he majorityo f cellsw ere myelinatedin guineap igs( Thomsen,1 966;A bdel Rahmane t al.,1 998)a ndi n cats( $poendlin1, 972). 

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