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Multiple Choice
A sarcomere is best defined as which of the following?
A
A protein that stores oxygen in muscle cells
B
A type of connective tissue surrounding muscle
C
A neurotransmitter released at the neuromuscular junction
D
The functional contractile unit of a muscle fiber
Verified step by step guidance
1
Understand the structure of a sarcomere: A sarcomere is the smallest functional unit of a muscle fiber, located between two Z-discs. It is responsible for muscle contraction and is composed of actin (thin filaments) and myosin (thick filaments).
Learn the role of the sarcomere in muscle contraction: During contraction, the sarcomere shortens as the actin and myosin filaments slide past each other, a process known as the sliding filament theory.
Differentiate the sarcomere from other muscle-related components: Unlike connective tissue, neurotransmitters, or oxygen-storing proteins like myoglobin, the sarcomere is directly involved in the mechanical process of contraction.
Visualize the anatomy of the sarcomere: Key structures include the Z-discs (boundaries of the sarcomere), the A-band (region containing thick filaments), the I-band (region containing thin filaments), and the H-zone (center of the A-band where there is no overlap of filaments).
Confirm the correct definition: Based on the structural and functional characteristics, the sarcomere is best defined as 'The functional contractile unit of a muscle fiber.'