FIND ARTICLE

Volume: 
Issue: 
3
Date of issue: 

Extraocular muscles are characterized by excellent neuromuscular control (one axon inne- rvates about only 7 muscle fibres) which allowed high precision eye movements and normal, binocular vision. In comparison to skeletal muscles extraocular muscles are characterized by higher maximal shortening velocity and lower maximal isometric force, expressed by amount of force generated per cross sectional surface area unit. Besides of functional differences occurring between extraocular and skeletal muscles molecular differences are present such as higher proportion of fast myosin heavy chain isoforms, specific myosin heavy chain isoforms: extraocular (MyHC-eom) and tonic myosin heavy cha- in isoforms (MyHC-sto), continuous expression of developmental isoforms (MyHC-emb i MyHC-pn), higher density of sarcoplasmic reticulum calcium ion pumps (SERCA) in extraocular muscle fibres. It is not clear why extraocular muscles, in contrary to skeletal muscles are preferentially spared in musc- les diseases such as Duchenne’a or Becker muscular dystrophies and are preferentially susceptible to other diseases such a ocular myopathies. The causes of differences in susceptibility to skeletal muscle diseases in relation to extraocular muscles diseases remain unclear. They might be due to different ontogeny of this group of muscles. Extraocular muscles arise from unsegmented head mesoderm whe- reas skeletal muscles arise from segmented mesoderm.

Author of the article: 

The Editorial Board
Andrzej Łukaszyk - przewodniczący, Zofia Bielańska-Osuchowska, Szczepan Biliński, Mieczysław Chorąży, Aleksander Koj, Włodzimierz Korochoda, Leszek Kuźnicki, Aleksandra Stojałowska, Lech Wojtczak

Editorial address:
Katedra i Zakład Histologii i Embriologii Uniwersytetu Medycznego w Poznaniu, ul. Święcickiego 6, 60-781 Poznań, tel. +48 61 8546453, fax. +48 61 8546440, email: mnowicki@ump.edu.pl

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