PHYSIOLOGY
SKELETAL MUSCLE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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the H zone
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2 sarcomeres and thick filaments
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parts of 2 adjacent sarcomeres and thin fiaments
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All of the above
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Detailed explanation-1: -The light bands are called I bands and contain only thin filament s. The dark bands are called A bands and contain thick and thin filaments, with the thick filaments running the entire length of the A band. Thus the length of the thick filament determines the length of the A band.
Detailed explanation-2: -– The A-band contains both thick and thin filaments and is the center of the sarcomere that spans the H zone. During contraction, the H-zone, I-band, the distance between Z-lines, and the distance between M-lines all become smaller. However, the A band’s size remains constant during contraction.
Detailed explanation-3: -The anisotropic band contains both thick and thin filaments. Within the A-band is a paler region called the H-zone (from the German “heller", brighter). Named for their lighter appearance under a polarization microscope. H-band is the zone of the thick filaments that has no actin.