(二)横纹肌细胞的细微结构 1.肌原纤维和肌节 A band (dark I band (light) H zone Thin filament 372(Actin) Thick filament (Myosin Z line M line Z line Sarcomere（二）横纹肌细胞的细微结构 1. 肌原纤维和肌节