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| 1 | |
Which of the following characterizes both skeletal and smooth muscle cells? |
| | A) | voluntary control |
| | B) | multinucleated |
| | C) | striated |
| | D) | excitable |
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| 2 | |
The "muscular system" includes muscles in which of these locations? |
| | A) | in the wall of the stomach |
| | B) | around the pupil of the eye |
| | C) | surrounding the orbit |
| | D) | in the wall of the heart |
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| 3 | |
How do skeletal muscle fibers get multiple nuclei? |
| | A) | fusion of embryonic myoblasts |
| | B) | multiple mitotic divisions without cytokinesis |
| | C) | both a and b |
| | D) | neither a nor b |
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| 4 | |
In skeletal muscle fibers, where do calcium ions occur at varying concentrations? |
| | A) | in the terminal cisternae of the sarcoplasmic reticulum |
| | B) | throughout the sarcoplasm |
| | C) | in regions where the thin and thick filaments overlap |
| | D) | all of the above |
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| 5 | |
In what order would a scalpel first penetrate these layers of connective tissue upon cutting into the biceps brachii muscle: (1) endomysium (2) epimysium (3) perimysium |
| | A) | 1, 3, 2 |
| | B) | 2, 3, 1 |
| | C) | 2, 1, 3 |
| | D) | 3, 2, 1 |
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| 6 | |
Which list of muscle structures proceeds from smaller to larger in diameter? |
| | A) | myofilament, fascicle, muscle fiber, myofibril |
| | B) | fascicle, myofibril, muscle fiber, myofilament |
| | C) | myofilament, myofibril, muscle fiber, fascicle |
| | D) | myofibril, fascicle, muscle fiber, myofilament |
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| 7 | |
What are satellite cells? |
| | A) | epithelial stem cells |
| | B) | part of the epimysium |
| | C) | unfused myoblasts |
| | D) | part of the endomysium |
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| 8 | |
Blood vessels and nerve fibers that supply skeletal muscle fibers must penetrate the |
| | A) | epimysium, perimysium, and endomysium |
| | B) | sarcolemma and superficial fascia |
| | C) | both a and b |
| | D) | neither a nor b |
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| 9 | |
Synaptic knobs are to axons as ____________ are to sarcolemmae, in that both are structural modifications involved in transmitting electrochemical signals across the synaptic cleft. |
| | A) | synaptic vesicles |
| | B) | motor end plates |
| | C) | sarcoplasmic reticula |
| | D) | transverse tubules |
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| 10 | |
Skeletal muscle contraction involves which of the following events? |
| | A) | a nerve impulse followed by a muscle impulse |
| | B) | release of calcium ions from terminal cisternae |
| | C) | tropomyosin moving to expose active sites on actin molecules |
| | D) | all of the above |
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| 11 | |
Of the following, which is the first to occur during muscle contraction? |
| | A) | actin slides past myosin |
| | B) | sarcomeres shorten |
| | C) | crossbridges link thick and thin filaments |
| | D) | myofibrils shorten and pull on ends of sarcolemma |
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| 12 | |
In the sliding filament mechanism, crossbridges are |
| | A) | myosin heads that bind to active sites on a thin filament |
| | B) | actin heads that bind to active sites on another thin filament |
| | C) | chemical bonds that pull a thick filament toward the center of a sarcomere |
| | D) | all of the above |
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| 13 | |
Interactions between thick and thin filaments during muscle contraction occur in which sequence? |
| | A) | attach, detach, pivot, return |
| | B) | attach, pivot, detach, return |
| | C) | detach, pivot, return, attach |
| | D) | pivot, attach, detach, return |
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| 14 | |
What actually shortens when a muscle fiber contracts? |
| | A) | thick and thin filaments |
| | B) | A bands, M lines, and Z discs |
| | C) | sarcomeres, H zones, and I bands |
| | D) | both b and c |
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| 15 | |
How many motor end plates does a typical skeletal muscle fiber contain? |
| | A) | only one |
| | B) | one at each end |
| | C) | dozens scattered along the sarcolemma |
| | D) | too variable to determine |
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| 16 | |
Rigor mortis demonstrates that skeletal muscle tissue |
| | A) | normally requires energy to end as well as to start a contraction |
| | B) | can survive and function for some time after the heart stops beating |
| | C) | maintains powerful contractions even with no ATP, until autolysis occurs |
| | D) | all of the above |
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| 17 | |
For any given muscle, the total force exerted by a contraction depends on |
| | A) | the length of each muscle fiber |
| | B) | the number of activated motor units |
| | C) | the type of contraction |
| | D) | the degree of muscle tone prior to contraction |
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| 18 | |
Physical conditioning can effectively decrease the proportion of which type of muscle fibers? |
| | A) | slow |
| | B) | intermediate |
| | C) | fast |
| | D) | none of the above |
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| 19 | |
Reflecting their different needs, fast muscle fibers contain large ____________ reserves whereas slow fibers contain the oxygen-carrying pigment ____________. |
| | A) | glycogen; myoglobin |
| | B) | fat; hemoglobin |
| | C) | myoglobin; glycogen |
| | D) | hemoglobin; myoglobin |
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| 20 | |
An overdose of cholinesterase inhibitors could produce effects most similar to those of |
| | A) | flaccid paralysis |
| | B) | tetanus |
| | C) | Botox treatments |
| | D) | botulism |
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| 21 | |
Among the patterns of fascicle arrangements, ____________ muscles can move their tendons farther but ____________ muscles of the same size are stronger. |
| | A) | parallel; pennate |
| | B) | convergent; parallel |
| | C) | circular; convergent |
| | D) | pennate; circular |
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| 22 | |
In the limbs, the insertion of a muscle typically lies |
| | A) | lateral to the origin |
| | B) | proximal to the origin |
| | C) | distal to the origin |
| | D) | at its origin |
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| 23 | |
In terms of ability to produce ATP, cardiac muscle fibers are most like |
| | A) | fast skeletal muscle fibers |
| | B) | intermediate skeletal muscle fibers |
| | C) | slow skeletal muscle fibers |
| | D) | smooth muscle fibers |
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| 24 | |
Z discs are to skeletal muscle as ____________ are to smooth muscle. |
| | A) | myofilaments |
| | B) | sarcomeres |
| | C) | transverse tubules |
| | D) | dense bodies |
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| 25 | |
Aging affects the muscular system in all of the following ways except |
| | A) | decrease in diameter of skeletal muscle fibers |
| | B) | decrease in amount of connective tissue within muscles |
| | C) | decrease in number of myofibrils and myofilaments in existing muscle fibers |
| | D) | decrease in ability to recover from disease or injury |
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