This image was obtained from a longitudinal section of skeletal muscle using a 60x oil immersion objective. The increased resolution is helpful in viewing sarcomeres.
Skeletal muscle cells (or fibers) are filled with tightly packed myofibrils. Myofibrils show an alternating series of striations due to the repeating sarcomeres. Each sarcomere is 2 to 3 µm long and extends from one Z line to the next.
Look for areas (#1, #2 and #3) where striations can be identified. Identify the bands in this higher magnification image of several sacromeres.
A band - the main dark band
I band - the main light band
Z line - thin dark line in the middle of the I band
H band - thin light band in the middle of the A band