Multiple Choice
In the sliding filament theory of skeletal muscle contraction, which structure actually shortens as the muscle contracts?
9. Muscle Tissue
Sliding Filament Theory and the Sarcomere
Multiple Choice
During a muscle contraction, the ___________ pulls on the ___________, shortening the muscle.
A
Actin: Myosin.
B
Myosin: Sarcomere.
C
Sarcomere: Actin.
D
Myosin: Actin.
Verified step by step guidance1
Understand the basic structure of a muscle fiber, which includes myofibrils composed of repeating units called sarcomeres.
Recognize that within the sarcomere, there are two main types of protein filaments: actin (thin filaments) and myosin (thick filaments).
Learn that during muscle contraction, the myosin heads bind to specific sites on the actin filaments, forming cross-bridges.
Know that the myosin heads then pivot, pulling the actin filaments toward the center of the sarcomere, which shortens the muscle.
Identify that the correct sequence of interaction during muscle contraction is 'Myosin pulls on Actin,' leading to the shortening of the muscle.
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