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Medical Term:


Pronunciation: mi'o-fil'a-ments


The ultramicroscopic threads of filamentous proteins making up myofibrils in striated muscle. Thick ones contain myosin and thin ones mostly actin; thick and thin myofilaments also occur in smooth muscle fibers but are not regularly arranged in discrete myofibrils and thus do not impart a striated appearance to these cells.

© Copyright 2017 Wolters Kluwer. All Rights Reserved. Review Date: Sep 19, 2016.