PHYSIOLOGY
SKELETAL MUSCLE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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thin
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thick
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Either A or B
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None of the above
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Detailed explanation-1: -The bipolar thick filament is formed of approximately 300 myosin molecules and their associated proteins (Craig & Offer, 1976; Luther, Munro, & Squire, 1981). It has a strictly uniform dimension of 1.6 µm in length and 15 nm in diameter, which is independent of the type of muscle fiber (Huxley, 1963).
Detailed explanation-2: -Thus visualized, myosin filaments appear thicker than actin filaments by a much smaller margin than in conventional thin sections, and particularly so for rigor muscle.
Detailed explanation-3: -The thick filament, myosin, has a double-headed structure, with the heads positioned at opposite ends of the molecule. During muscle contraction, the heads of the myosin filaments attach to oppositely oriented thin filaments, actin, and pull them past one another.