What happens during muscle contraction to the length of each myosin and actin filament?
Correct answer: D. Z- lines get close
- A. A band becomes short
- B. | band elongates
- C. There is no change in sarcomere
- D. Z- lines get close
Explanation
Option D is correct since the sarcomere shortens during muscle contraction. A sarcomere is a structure bound by two consecutive Z lines. So when the sarcomere shortens, the Z-lines come closer. Option A is incorrect since, during muscle contraction, the width of the A-band does not change. Option B is incorrect since the I-band shortens and does not elongate during muscle contraction. Option C is incorrect since the width of the sarcomere reduces during muscle contraction. The changes observed during muscle contraction are as follows :
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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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