Each muscle fiber contains long threads that extend along its entire length. These are called as:
Correct answer: D. Myofibrils
- A. Myosin
- B. Microtubules
- C. Microfilaments
- D. Myofibrils
Explanation
Myofibrils are the long threads or cylindrical structures found within muscle fibers. They are composed of repeating units called sarcomeres and are responsible for muscle contraction. Myofibrils consist of thick and thin filaments (myofilaments), including myosin and actin, organized in a highly ordered manner. The myofibrils extend the entire length of the muscle fiber and are responsible for its striated appearance. They are the functional units of muscle contraction and generate force by sliding the thick and thin filaments past each other.
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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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