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Section Reveiw 7.6
flashcards 7.6
Question | Answer |
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Why does the number of muscle fibers in a motor unit vary? | Muscles that must produce movements of great precision have fewer muscle cells per motor unit, allowing very fine control. Muscles designed for coarser movements have many more muscle cells in each motor unit. |
What is meant by all-or-none principle of muscle cell contraction? | When a muscle cell is stimulated to contract, it does so completely and then relaxes completely untill another nerve impulse reaches it. |
fascia | a tough translucent sheath that binds the muscle together. |
muscle fiber | composed of millions of individual muscle cells. |
myofibril | long cylinders inside muscle cell that contain the contraction machinery. |
sarcomere | overlapping protein fibers which compose myofibrils. |
neuromuscular junction | point of contact between a motor neuron and a skeletal muscle cell. |
a group of fibers stimulated to contact simultaneously in connection to a single motor nerve. | motor unit |