1) microstructure of skeletal muscle fiber O long cylindrical 10-100um in diameter, 1-40mm long 2 multinucleate, nuclei are ovoid distributed under sarcolemma 8 filled with long itudinal parallel-arranged myofibrils1) microstructure of skeletal muscle fiber ① long cylindrical 10-100um in diameter,1-40mm long ② multinucleate, nuclei are ovoid, distributed under sarcolemma ③ filled with longitudinal parallel-arranged myofibrils