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| 1 | |
The elasticity of skeletal muscle fibers is primarily due to the presence of this protein: (pp. 421-422; table 12.1) |
| | A) | titin |
| | B) | globular actin |
| | C) | troponin |
| | D) | collagen |
| | E) | tropomyosin |
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| 2 | |
T-tubules are extensions of the______________ in skeletal muscle (p. 421; table 12.1) |
| | A) | sarcoplasmic reticulum |
| | B) | plasma membrane |
| | C) | junctional folds |
| | D) | cytoskeleton |
| | E) | thick filament |
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| 3 | |
All of the following are structural components of the neuromuscular junction except: (p. 426; fig 12.7; table 12.2) |
| | A) | active zones |
| | B) | junctional folds |
| | C) | basement membrane |
| | D) | t-tubules |
| | E) | acetylcholine receptors |
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| 4 | |
After the power stroke has occurred during skeletal muscle contraction, what must occur in order for the acto-myosin cross-bridge to be released? (p. 431) |
| | A) | ATP must be cleaved |
| | B) | myosin must be de-phosphorylated |
| | C) | ATP must bind with the myosin head |
| | D) | Ca2+ must bind with myosin |
| | E) | troponin must bind with tropomyosin |
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| 5 | |
During excitation contraction coupling, Ca2+ binds troponin in both smooth and skeletal muscle. (pp. 429, 446) |
| | A) | True |
| | B) | False |
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| 6 | |
Smooth muscle is capable of mitosis and hyperplasia. (p. 445) |
| | A) | True |
| | B) | False |
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| 7 | |
If a person is completely bedridden, he/she can lose muscle strength at the rate of 3% per day. (p.448, table 12.6) |
| | A) | True |
| | B) | False |
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| 8 | |
The ability of the muscle cell membrane to respond to stimuli with electric changes is known as |
| | A) | excitability. |
| | B) | conductivity. |
| | C) | extensibility. |
| | D) | elasticity. |
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| 9 | |
The ability of the muscle cell to stretch under tension is known as |
| | A) | excitability. |
| | B) | conductivity. |
| | C) | extensibility. |
| | D) | elasticity. |
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| 10 | |
The ability of the muscle cell to return to its initial length after being stretched is called |
| | A) | excitability. |
| | B) | conductivity. |
| | C) | extensibility. |
| | D) | elasticity. |
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| 11 | |
Transverse tubules release calcium ions during muscle contraction. |
| | A) | True |
| | B) | False |
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| 12 | |
Which of the following is a regulatory protein of muscle? |
| | A) | actin |
| | B) | myosin |
| | C) | tropomyosin |
| | D) | titin |
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| 13 | |
Elastic filaments are composed of |
| | A) | myosin. |
| | B) | actin. |
| | C) | titin. |
| | D) | troponin. |
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| 14 | |
The segment from one Z disc to the next is called a(n) |
| | A) | A band. |
| | B) | sarcomere. |
| | C) | H band. |
| | D) | I band. |
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| 15 | |
When fine control of a muscle is required, the motor units are small. |
| | A) | True |
| | B) | False |
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| 16 | |
Flaccid paralysis can be caused by |
| | A) | pesticides. |
| | B) | cholinesterase inhibitors. |
| | C) | curare. |
| | D) | acetylcholinesterase. |
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| 17 | |
The resting membrane potential (RMP) for a skeletal muscle cell is |
| | A) | -90mV. |
| | B) | -30mV. |
| | C) | 1.5mV. |
| | D) | 12 V. |
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| 18 | |
In a muscle contraction, the myofilaments shorten. |
| | A) | True |
| | B) | False |
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| 19 | |
The time in which the muscle will not respond to a new stimulus is called the |
| | A) | latent period. |
| | B) | contraction phase. |
| | C) | relaxation phase. |
| | D) | refractory period. |
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| 20 | |
For a muscle to lift a heavier weight, the individual muscle fibers contract more strongly. |
| | A) | True |
| | B) | False |
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| 21 | |
If you attempt to lift a heavy object but it doesn't move, what type of contraction have you performed? |
| | A) | concentric |
| | B) | eccentric |
| | C) | isotonic |
| | D) | isometric |
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| 22 | |
If you are drinking and put the glass down, this is a(an) __________ contraction. |
| | A) | concentric |
| | B) | eccentric |
| | C) | isotonic |
| | D) | isometric |
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| 23 | |
A brief activity using maximum muscular effort is fueled best by the |
| | A) | phosphagen system. |
| | B) | aerobic system. |
| | C) | glycogen-lactic acid system. |
| | D) | citric acid system. |
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| 24 | |
Which of the following statements about slow-twitch muscle fibers is false? |
| | A) | Slow-twitch muscle fibers are smaller than fast-twitch fibers. |
| | B) | Slow-twitch muscle fibers are anaerobic. |
| | C) | Slow-twitch muscle fibers are fatigue resistant. |
| | D) | Slow-twitch muscle fibers have abundant mitochondrion and myoglobin. |
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| 25 | |
A stronger muscle contraction produced by a series of action potentials being sent to a motor unit is known as recruitment. |
| | A) | True |
| | B) | False |
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| 26 | |
Acetylcholine and norepinephrine cause some smooth muscle cells to contract and yet inhibit cell contraction in others, depending on the type of membrane receptors present. |
| | A) | True |
| | B) | False |
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| 27 | |
Smooth muscle is more sensitive to a difference in resting muscle length on peak contraction potential than skeletal muscle. |
| | A) | True |
| | B) | False |
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| 28 | |
The thick myofilament consists of many molecules of this protein: |
| | A) | myosin |
| | B) | actin |
| | C) | tropomyosin |
| | D) | troponin |
| | E) | ATPase |
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| 29 | |
The sarcomeres are separated by: |
| | A) | A bands |
| | B) | I bands |
| | C) | H bands |
| | D) | Z discs |
| | E) | A discs |
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| 30 | |
One nerve fiber and all the muscle fibers it innervates are collectively called a: |
| | A) | motor unit |
| | B) | somatic motor group |
| | C) | recruitment group |
| | D) | fatigue unit |
| | E) | synapse |
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| 31 | |
This chemical carries the stimulating message across the neuromuscular junction: |
| | A) | synapse |
| | B) | myosin |
| | C) | potassium |
| | D) | gamma-aminobutyric acid |
| | E) | acetylcholine |
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| 32 | |
During excitation-contraction coupling, calcium ions bind to this skeletal muscle protein: |
| | A) | acetylcholinesterase |
| | B) | troponin |
| | C) | actin |
| | D) | myosin |
| | E) | ATPase |
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| 33 | |
The myosin heads bind to a monomer of this protein: |
| | A) | tropomyosin |
| | B) | troponin |
| | C) | G-actin |
| | D) | acetylcholinesterase |
| | E) | ATPase |
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| 34 | |
When the muscle action potential stops, calcium ions are pumped from the cytosol back into the: |
| | A) | terminal cisternal |
| | B) | transverse tubules |
| | C) | thick filaments |
| | D) | troponin |
| | E) | mitochondria |
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| 35 | |
_____ occurs when a muscle twitches more strongly as stimulation frequency is increased to 20/sec. |
| | A) | graded response |
| | B) | Treppe |
| | C) | Threshold |
| | D) | Tetany |
| | E) | Isometric contraction |
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| 36 | |
Fatigue can be caused by all of the following except: |
| | A) | low acetylcholine supplies |
| | B) | low pH in sarcoplasm |
| | C) | excess of myoglobin |
| | D) | excess of lactic acid |
| | E) | reduced ATP concentrations |
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| 37 | |
Fast-twitch fibers: |
| | A) | have a lot of myoglobin |
| | B) | mainly synthesize ATP by aerobic respiration |
| | C) | have more mitochondria |
| | D) | are white |
| | E) | are very resistant to fatigue |
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| 38 | |
Smooth muscles: |
| | A) | have Z-discs |
| | B) | lack T-tubules |
| | C) | contain troponin |
| | D) | are multinucleate |
| | E) | are innervated by somatic nerve fibers |
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