PHYSIOLOGY
SKELETAL MUSCLE
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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tropnin
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tropomyosin
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actin and myosin
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ADP and ATP
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Detailed explanation-1: -Most of the cytoplasm consists of myofibrils, which are cylindrical bundles of two types of filaments: thick filaments of myosin (about 15 nm in diameter) and thin filaments of actin (about 7 nm in diameter).
Detailed explanation-2: -Muscles are composed of myofibrils containing the myofilaments actin and myosin. Under the influence of adenosine triphosphate (ATP), actin and myosin form a contractile compound, actomyosin, which is required for muscle contraction.
Detailed explanation-3: -The actin to myosin filament ratio varies from 3 to 4 within each individual myofibril. The described variability of the actin filaments arrays leads to several difficulties in an explanation of the mechanism of muscular contraction.
Detailed explanation-4: -A sarcomere is the basic contractile unit of a myocyte (muscle fibre). A sarcomere is composed of two main protein filaments (thin actin and thick myosin filaments) which are the active structures responsible for muscular contraction.