Zoology - Locomotion and Movement Question with Solution | TestHub

The change in the tension in the skeletal muscle is called muscle contraction. The muscle contraction is achieved by the sliding of actin filaments over myosin filaments. During muscle contraction, two Z lines come close, the Light band (I band) shortens and the length of dark band (A band) remains the same. H zone or Henson's zone is the area in the middle of the dark band where actin filaments don't overlap myosin filaments in a relaxed muscle fibre. During contraction, the actin filaments completely overlap the myosin filaments and thus there is no H zone.