PHYSIOLOGY
MICROSCOPIC MUSCLE ANATOMY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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I bands
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Z bands
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H bands
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A bands
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Detailed explanation-1: -The darker bands are called anisotropic bands (A bands). Together the I-bands and A-bands contribute to the striated appearance of skeletal muscle. Isotropic bands indicate the behavior of polarized light as it passes through I bands. Diagrams provide an indication of what I and A Bands look like, through a microscope.
Detailed explanation-2: -The striated appearance of skeletal muscle tissue is a result of repeating bands of the proteins actin and myosin that are present along the length of myofibrils. Dark A bands and light I bands repeat along myofibrils, and the alignment of myofibrils in the cell causes the entire cell to appear striated or banded.
Detailed explanation-3: -The dark staining region in the centre of the sarcomere is called the A (anisotropic) band. The lighter staining band, through which the Z-line passes is called the I (isotropic) band. A diagram of a muscle sarcomere is shown below.
Detailed explanation-4: -Dark bands contain actin and myosin filaments side by side. Light bands contain only actin filaments.