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Related to thin filament: Thick filament
one of the contractile elements in muscular fibers and other cells; in skeletal muscle, the actin filaments are about 7.5 nm wide and 1 mcm long, and attach to the transverse Z filaments.
Synonym(s): thin filament
In a sarcomere, one of the collection of contractile filaments made primarily of actin, seen microscopically.