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16 Cards in this Set
- Front
- Back
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what are skeletal muscle |
the muscles that surround the skeleton (bones) |
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what are skeletal muscles composed of |
numerous muscle fibers or muscle cells |
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is muscle cell an excitable cell? |
yes |
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what does it mean that a muscle is an excitable cell |
it generates and propagates action potential |
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what are muscle fibers innervated by |
nerve fibers |
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what are nerve fibers |
motor neurons |
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why are nerve fibers innervated b nerve fibers |
to cause muscle contraction |
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how many muscle fibers does one nerve fiber usually innercate |
multiple |
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how many myofibrils oes a muscle fiber contain |
numerous (hundred-thousands) |
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what is the sarcolemma |
the membrane of the muscle fiber that surrounds myofibrils |
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what are spaces between myofibrils filled with |
intracellular fluid called sarcoplasm |
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each myofibril is composed of how many contractile filaments |
two |
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what are each contractile filament called |
myofilament (protein) |
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what are the thick filaments called |
myosin |
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what are the thin filaments called |
actin |
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how thick are muscle fiber |
10-80 micrometers |
