thin myofilament e lum long, 5nm in diameter ● composed of: A actin- spherical monomers of globular actin arranged in two row and twisted- filamentous 肌动蛋白单体原肌球蛋白 肌原蛋自 T actin, each monomer has anie OO binding site 肌球蛋白杆 粗肌丝 肌球蛋白头 横桥)---thin myofilament: 1um long, 5nm in diameter composed of: A. actin- spherical monomers of globular￾actin arranged in two row and twisted- filamentous actin, each monomer has binding site