Multiple Choice
In the context of sliding filament theory, what structural feature causes skeletal muscle fibers to appear striated under the microscope?
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9. Muscle Tissue
Sliding Filament Theory and the Sarcomere
Multiple Choice
In the context of sliding filament theory, what is the basic functional (contractile) unit of skeletal muscle?
A
Myofibril
B
Epimysium
C
Fascicle
D
Sarcomere
Verified step by step guidance1
Understand that the sliding filament theory explains how muscles contract by the interaction of actin and myosin filaments within muscle fibers.
Recognize that skeletal muscle is organized into several structural levels: muscle → fascicles → muscle fibers (cells) → myofibrils → sarcomeres.
Identify that the myofibril is a long, cylindrical organelle within muscle fibers composed of repeating units called sarcomeres.
Know that the sarcomere is the segment between two Z-discs and contains the actin (thin) and myosin (thick) filaments whose sliding causes contraction.
Conclude that the sarcomere is the basic functional (contractile) unit of skeletal muscle because it is the smallest unit capable of contraction according to the sliding filament theory.
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