Question

In the resting state of muscle, the H zone is the

• A. Central part of thin filament overlapped with thick filament
• B. Central part of thick filament not overlapped with thin filament
• C. Central part of thin filament not overlapped with thick filament
• D. Central part of thick filament overlapped with thin filament

Answer 1

The correct option is B Central part of thick filament not overlapped with thin filament

The portion between two successive Z lines is known as the sarcomere. ‘A’ band and ‘I’ band are arranged alternatively throughout the myofibrils. The A band is the dark band of the sarcomere, also called the anisotropic band. The thick filaments, which contain the protein myosin, and the thin filaments, which contain the protein actin, are both present in the A band. The light bands contain only actin and are called I bands. In a resting state, the edges of the thin filaments overlap on either side of the thick filaments.
The central part of the thick filaments that is not overlapped by thin filaments is called the ‘H’ zone.