The sarcolemma of muscle fibers fold inwards and form system of tubes which runs through the sarcoplasm called:
Correct answer: D. Transverse tubules
- A. Myofilaments
- B. Z-lines
- C. Sarcoplasmic reticulum
- D. Transverse tubules
Explanation
Transverse tubules, also known as T-tubules, are invaginations of the sarcolemma that penetrate deep into the sarcoplasm of muscle fibers. These tubular structures run perpendicular to the myofibrils and are closely associated with the sarcoplasmic reticulum. T-tubules allow the action potential (electrical signal) to rapidly penetrate into the interior of the muscle fiber, ensuring synchronized contraction of the myofibrils. They are essential for the excitation-contraction coupling process, which links the electrical excitation of the muscle fiber to the contraction of the myofilaments.
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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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