How does the arrangement of a muscle's fascicles affect its function?

• A. It determines the muscle's range of motion and power.
• B. It regulates the amount of blood supplied to the muscle.
• C. It controls the speed of nerve impulses in the muscle.
• D. It dictates the type of neurotransmitter released at the neuromuscular junction.

Answer: (A)

Verified step by step guidance

1. Understand the structure of a muscle: Muscles are composed of bundles of fibers called fascicles, which are arranged in specific patterns. These patterns include parallel, pennate, convergent, and circular arrangements.
2. Analyze the relationship between fascicle arrangement and range of motion: Fascicles arranged in parallel allow for greater shortening of the muscle, which increases the range of motion. For example, muscles with long parallel fascicles can contract over a greater distance.
3. Examine the relationship between fascicle arrangement and power: Pennate muscles, where fascicles attach obliquely to a central tendon, generate more power because they pack more fibers into a given area. However, their range of motion is limited compared to parallel muscles.
4. Eliminate irrelevant options: The arrangement of fascicles does not regulate blood supply, control nerve impulse speed, or dictate neurotransmitter release. These functions are governed by other physiological systems, such as the circulatory and nervous systems.
5. Conclude the correct answer: The arrangement of a muscle's fascicles primarily determines its range of motion and power, as these are directly influenced by the structural organization of the muscle fibers.