During muscle contraction, which parts of a sarcomere change in length?
Correct answer: D. H zone and I band
- A. H zone and myosin
- B. H zone and actin
- C. I band and A band
- D. H zone and I band
Explanation
The H zone and I band are two regions of the sarcomere, which is the basic unit of muscle contraction. The H zone is the region in the center of the sarcomere that contains myosin filaments but no actin filaments. The I band is the region on either side of the H zone that contains actin filaments but no myosin filaments. During muscle contraction, the H zone and I band both decrease in length as the myosin and actin filaments slide past each other, causing the sarcomere to shorten. The A band, which is the region that contains both myosin and actin filaments, remains the same length during muscle contraction.
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About Support and Movement
Support and movement covers the axial and appendicular skeleton, bone structure, joints and the arrangement of skeletal muscles. Muscle contraction is explained through actin, myosin, sliding filaments, calcium ions and ATP, while arthritis is distinguished as a disorder of joints rather than a normal part of movement.
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