What is the functional contractile unit of a skeletal muscle fiber bounded by two Z-discs?
Answer and explanation
Correct answer: A. Sarcomere
- Step 1: A skeletal muscle cell contains bundles of myofibrils comprised of repeating functional segments.
- Step 2: The region between two consecutive Z-lines containing actin and myosin filaments is the sarcomere, the fundamental unit of contraction.
Answer
Sarcomere.
Why not the others: 'Myofibril' is the cylindrical organelle running the length of the muscle fiber; 'Sarcolemma' is the specialized plasma membrane of the muscle fiber; 'Sarcoplasmic reticulum' stores and releases calcium ions.
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