What is the A band made up of?

The A band, found in striated muscle fibers, is primarily composed of thick filaments made of myosin, along with some overlapping thin filaments made of actin. It appears dark under a microscope due to the density of these filaments. The A band is crucial for muscle contraction, as it contains the regions where myosin and actin interact during the sliding filament mechanism. Additionally, the A band includes the H zone, which is the lighter region in the center where only myosin is present.