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Multiple Choice
Which of the following best describes the electrical activity observed in a muscle when grip strength increases?
A
Action potentials are completely absent during stronger grips.
B
The electrical activity remains unchanged regardless of grip strength.
C
There is an increase in the frequency and amplitude of action potentials.
D
There is a decrease in the frequency of action potentials.
Verified step by step guidance
1
Understand the concept of action potentials: Action potentials are electrical signals generated by neurons and muscle cells to facilitate communication and contraction. They are characterized by changes in frequency and amplitude depending on the stimulus strength.
Relate grip strength to muscle activity: When grip strength increases, more motor units (groups of muscle fibers and their associated motor neurons) are recruited to generate the required force. This recruitment leads to increased electrical activity in the muscle.
Analyze the relationship between action potential frequency and amplitude: As more motor units are activated, the frequency of action potentials increases because more signals are sent to recruit additional muscle fibers. Additionally, the amplitude of the electrical activity may increase due to the summation of signals from multiple motor units.
Eliminate incorrect options: Action potentials are not absent during stronger grips; they are essential for muscle contraction. Electrical activity does not remain unchanged, as grip strength directly influences the recruitment of motor units. A decrease in frequency is incorrect because stronger grips require more frequent signaling.
Conclude the correct observation: The electrical activity observed in a muscle during stronger grips is characterized by an increase in both the frequency and amplitude of action potentials, reflecting the recruitment of additional motor units and enhanced signaling.