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20 Cards in this Set
- Front
- Back
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Release of calcium from sacroplasmic reticulum
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Muscle contraction caused by
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Calcium binds to this
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Troponin
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Troponin moves tropomysin to expose...
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binding sites on thin filaments
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Attaches to binding sites
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Helically-arranged myosin heads of thick filament
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Myosin heads pivot to do what...
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move cross-bridged thin filaments towards the center of the sarcomere
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ATP bonds with myosin heads to break what...
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cross-bridge and return myosin to pre-pivot position
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Myosin head now does what...
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cross-bridge further along thin filament
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When stimulation ends, this occurs...
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calcium returns to the terminal cisternae
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Motor unit consists of
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one motor neuron and all the muscle fibers that it innervates
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Motor unit traits
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Muscles include a number of motor units
Means for regulating the strength of contraction Stimulation is all-or-nothing; the motor neuron transmitting the impulse will stimulate all fibers it innervates |
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Where impsule reaches individual nerve fiber
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Neuromuscular junction
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Release of acetylcholine at the junction does what?
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Stimulates the sarcoplasmic reticulum to release calcium.
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Skeletal muscle types
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Fast
Intermediate Slow |
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Fast skeletal muscle characteristics
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Large diameter
Densely packed myofibrils Relatively few mitochondria Called white fibers due to lack of myoglobin Majority of skletal muscle fibers in the body |
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Intermediate skeletal muscle characteristics
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Resemble fast fibers
Greater resistance to fatigue |
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Slow skeletal muscle characteristics
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Smaller diameter
Contract more slowly Called red due to myoglobin |
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Cardiac muscle fibers are
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arranged in thick bundles within the heart wall
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Cardiac muscle have how many nuclei
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one to two
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Cardiac muscle is different to skeletal muscle in...
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number of nuclei
shorter and thicker |
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Intercalated discs
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Y-shaped branch junctions of cardiac muscle fibers joined to adjacent muscle fibers
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