Multiple Choice
Which region of the sarcomere does not change in length during muscle contraction?
9. Muscle Tissue
Sliding Filament Theory and the Sarcomere
Multiple Choice
In the context of sliding filament theory, what is the basic contractile unit of a skeletal muscle fiber?
A
Myofibril
B
Sarcomere
C
Sarcolemma
D
Fascicle
Verified step by step guidance1
Understand that the sliding filament theory explains how muscle contraction occurs at the microscopic level within skeletal muscle fibers.
Recall that skeletal muscle fibers contain many myofibrils, which are long, cylindrical structures composed of repeating units.
Identify that the basic contractile unit within a myofibril is called the sarcomere, which is the segment between two Z discs.
Recognize that the sarcomere contains the actin (thin) and myosin (thick) filaments whose interaction causes contraction by sliding past each other.
Note that other options like myofibril, sarcolemma, and fascicle refer to larger structures or membranes, not the fundamental contractile unit.
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