1.2 The structure of skeletal muscle fiber under em 12.1 Myofibril: myofilament(肌丝) thick myofilament and thin myofilament) ()Arrangement: 一个肌节M线 个肌线 a AMAN. 粗肌丝 细肌丝 M线横切面H带横切面 A带横切面带横切面1.2 The structure of skeletal muscle fiber under EM 1.2.1 Myofibril: myofilament（肌丝） （thick myofilament and thin myofilament) (1) Arrangement：