NUTRITION
THE HUMAN BODY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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When muscles contract, what two landmarks are brought closer together?
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M lines
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Z lines
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L lines
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S lines
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Explanation:
Detailed explanation-1: -In electron micrographs of cross-striated muscle, the Z-line (from the German “zwischen” meaning between) appears in between the I-bands as a dark line that anchors the actin myofilaments. Surrounding the Z-line is the region of the I-band (for isotropic).
Detailed explanation-2: -Summary. According to the sliding filament theory, a muscle fiber contracts when myosin filaments pull actin filaments closer together and thus shorten sarcomeres within a fiber.
Detailed explanation-3: -The area between two Z lines, a sarcomere, can be considered to be the primary structural and functional unit directly responsible for muscle contraction.…
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