PHYSIOLOGY
SKELETAL MUSCLE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Very little control
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No control
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Extremely accurate control
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Moderate or average control
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Detailed explanation-1: -The size of the motor unit correlates with the function of the muscle. In muscles involved with fine, coordinated control, the motor units are very small with 3-5 muscle fibers per motor neuron. Muscles that control eye movement and muscles in our hands have relatively small motor units.
Detailed explanation-2: -In the hand and eye, fewer than 100 muscle fibers occupy a motor unit; in the lower leg, a single motor unit may contain as many as 1, 000 muscle fibers ( Generally, the larger the number of muscle fibers in a motor unit, the less precise the associated movements.
Detailed explanation-3: -Each muscle fiber is innervated by only one motor neuron. The actual group of muscle fibers in a muscle innervated by a single motor neuron is called a motor unit.
Detailed explanation-4: -The smallest motor units are in muscles that must produce very fine gradations of force: lumbricals: 100 fibers/unit. eye muscles: 5 fibers/unit.