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myofilament/myo·fila·ment/ (-fil´ah-ment) any of the ultramicroscopic threadlike structures composing the myofibrils of striated muscle fibers; thick ones contain myosin, thin ones contain actin, and intermediate ones contain desmin and vimentin.
Any of the ultramicroscopic filaments, made up of actin and myosin, that are the structural units of a myofibril.
Etymology: Gk, mys, L, filare, to spin
any of the numerous ultramicroscopic threadlike structures occurring in bundles in the myofibrils of striated muscle fibers. The thick filaments of myosin and the thin filaments of actin are together responsible for the contractile properties of muscle. Also present are intermediate filaments, of uncertain function. See also myofibril.
any of the ultramicroscopic threadlike structures composing the myofibrils of striated muscle fibers.