The fundamental contractile unit of the myofibril is:
Correct answer: C. Sarcomere
- A. Z-line
- B. Actin
- C. Sarcomere
- D. Sarcolemma
Explanation
The basic contractile unit of the myofibril is the sarcomere. It is a portion between two Z-lines and this specific unit undergoes contractility.
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About Muscle Contraction
Muscle contraction is explained by the sliding filament model, in which myosin heads pull actin filaments within sarcomeres using ATP. The topic covers calcium, troponin, tropomyosin, the neuromuscular junction and relaxation, with attention to how filament length stays almost constant while the sarcomere shortens.
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