Which of the following components is NOT part of the motor unit's function?

• A. Activates multiple muscle fibers
• B. Connects to nervous tissues
• C. Transmits signals to the brain
• D. Initiates muscle contractions

Answer: (C)

The function of a motor unit primarily involves the interaction between motor neurons and muscle fibers to facilitate muscle contractions. When a motor neuron is activated, it sends signals to multiple muscle fibers, causing them to contract. This is essential for movement and coordination in the body.

The correct answer, which indicates a component that is not part of the motor unit's function, directly highlights that transmitting signals to the brain is not a role performed by the motor unit itself. Rather, the motor unit transmits impulses from the brain or spinal cord to the muscles, leading to contraction, while signals traveling to the brain are managed by other neural pathways.

The other functions mentioned in the choices are integral to the role of a motor unit. Activating multiple muscle fibers ensures that the force applied during muscle contractions is adequate for the task at hand. Additionally, connecting to nervous tissues is crucial since the motor neuron must relay impulses effectively to communicate muscle activation. Initiating muscle contractions is a primary function of the motor unit, initiated by the action potentials generated in the motor neuron.