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18 Cards in this Set
- Front
- Back
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Sarcomere
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The repeating unit of a myofibril
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Motor unit
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One motor neuron and all the muscle fibers it innervates
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All-or-none law of skeletal muscle contraction
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An individual muscle fiber contracts with equal force in response to each action potential
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Muscle tone
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The state of partial contraction in a muscle, even when the muscle is not being used
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What kind of muscle tissue is striated?
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Skeletal muscle tissue
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Structures of a whole muscle
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a. epimysium b. muscle fibers (cells) c. fascicles |
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Parts of the sarcomere
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a. actin myofilament b. myosin myofilament c. H zone d. A band |
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When a muscle fiber contracts, what happens to: a. the distance between the Z disks b. the length of the A band c. the length of the I band d. the length of the H zone e. the length of the myosin myofilament f. the length of the actin myofilament |
a. reduced b. nothing c. reduced d. reduced e. nothing f. nothing |
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Acetylcholinesterase
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Enzyme that inactivates acetylcholine
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How does the membrane action potential get to the sarcoplasmic reticulum?
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It travels down the T-tubule
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Calcium ions are diffusing across the membrane of the sarcoplasmic reticulum. Is the cell beginning contraction or ending contraction?
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It is beginning to contract
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When a sarcomere contracts, what happens between the power stroke and the return stroke?
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They shorten
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What must happen after the action potential reaches the presynaptic terminal and before an action potential is established on the membrane of a muscle cell?
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ACh is released and travels across the synaptic cleft
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If a muscle is stiff, what is there not enough of in the muscle cells?
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Calcium ions
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A nerve is being stimulated with a submaximal stimulus. Are there any motor units that have been recruited?
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Yes
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A motor unit is recruited. What happens to the muscle fibers in that motor unit?
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The muscle fibers have contracted
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Lactic acid is building up in a muscle cell. What kind of respiration is occurring?
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Anaerobic respiration
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A muscle cell is using creatine phosphate to convert ADP into ATP. Does this require oxygen?
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No
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