Skeletal muscle, light micrograph. Longitudinal section of muscle fibres identified as skeletal, or voluntary, muscle as the fibre cytoplasm is filled with repetitive dark and light bands (sarcomeres) of contractile filaments, and the nuclei are displaced to the edge of fibres. The appearance of three nuclei apparently in the fibre centre is due to a fortuitous plane of section deep to the surface of the muscle fibre. Acrylic resin section, haematoxylin-eosin stain. Magnification: x500 when width printed at 10cm.