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1 | |
Impulses from one motor nerve fiber will cause the contraction of several muscle fibers. (p. 326) |
| | A) | True |
| | B) | False |
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2 | |
The bone on which a skeletal muscle has its "insertion" moves very little, or not at all when the muscle contracts. (p. 326) |
| | A) | True |
| | B) | False |
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3 | |
Muscles do not antagonize each other. If they did, there could be no movement of a joint.(p. 326) |
| | A) | True |
| | B) | False |
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4 | |
A muscle as a whole is surrounded by a connective tissue sheath called its fascicle. (p. 328) |
| | A) | True |
| | B) | False |
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5 | |
The term myofiber or muscle fiber is equivalent to a single muscle cell. (p. 328) |
| | A) | True |
| | B) | False |
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6 | |
Muscle fibers are so densely packed with protein filaments there is no room for nuclei, mitochondria, endoplasmic reticulum, and other structures typical of other cell types. (p. 329) |
| | A) | True |
| | B) | False |
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7 | |
The Z lines of striated muscle are dark lines in the middle of an A band. (p. 332) |
| | A) | True |
| | B) | False |
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8 | |
Skeletal muscle twitches, like nerve action potentials, always have the same strength or magnitude. (p. 328) |
| | A) | True |
| | B) | False |
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9 | |
Tetanus is a normal part of muscle contraction and should not be confused with the disease of the same name. (p. 340) |
| | A) | True |
| | B) | False |
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10 | |
A muscle contracts more strongly when lifting a 20-pound weight than when lifting a 5-pound weight. This is because more fibers are contracting, not because individual fibers contract harder. (p. 330) |
| | A) | True |
| | B) | False |
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11 | |
If a muscle is repeatedly stimulated and allowed to relax between stimuli, the successive contractions will be stronger. This phenomenon, known as treppe, or staircase effect, is thought to be due to accumulation of neurotransmitter in the neuromuscular cleft. (p. 340) |
| | A) | True |
| | B) | False |
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12 | |
During an isometric contraction, a muscle does not get any shorter. (p. 341) |
| | A) | True |
| | B) | False |
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13 | |
There is considerable neuronal convergence in somatic motor units, with several motor neurons often innervating an individual muscle fiber. (p. 330) |
| | A) | True |
| | B) | False |
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14 | |
One somatic motor neuron always leads to exactly one skeletal muscle fiber. (p. 330 ) |
| | A) | True |
| | B) | False |
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15 | |
Small motor units (for example, one neuron innervating 100-200 muscle fibers) are used more often than larger motor units (one neuron to 1,000 or more fibers). (p. 330) |
| | A) | True |
| | B) | False |
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16 | |
Thick filaments within muscle fibers consist primarily of myosin protein molecules whereas the thin filaments consist primarily of actin protein molecules. (p. 331) |
| | A) | True |
| | B) | False |
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17 | |
The I bands of a muscle fiber sarcomere contain only thin filaments. (p. 331) |
| | A) | True |
| | B) | False |
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18 | |
The A bands of a muscle fiber sarcomere contain only myosin protein molecules.(p. 331) |
| | A) | True |
| | B) | False |
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19 | |
Thick filaments do not get any shorter when a muscle contracts. (p. 333) |
| | A) | True |
| | B) | False |
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20 | |
When a muscle is at rest, the thick filaments are not attached to the thin filaments. (p. 334) |
| | A) | True |
| | B) | False |
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21 | |
The globular head of a myosin cross bridge contains an ATP-binding site and a nearby actin-binding site. (p. 335) |
| | A) | True |
| | B) | False |
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22 | |
A thick filament cannot let go of a thin filament at the end of its power stroke unless an additional ATP molecule is available to the globular head of the myosin cross bridge. (p. 335) |
| | A) | True |
| | B) | False |
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23 | |
To achieve coordinated muscle contraction, it is important that all the myosin cross bridges bind to the thin filaments and produce their power strokes in unison. (p. 334) |
| | A) | True |
| | B) | False |
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24 | |
The thicker a muscle fiber is, the more contractile force it can generate. (p. 346) |
| | A) | True |
| | B) | False |
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25 | |
Most muscles can shorten up to about 35% of their original resting length. (p. 340) |
| | A) | True |
| | B) | False |
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26 | |
Myosin cross bridges cannot link up with thin filaments as long as the protein, known as tropomyosin is in the way.(p. 336) |
| | A) | True |
| | B) | False |
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27 | |
Tropomyosin cannot get out of the way of myosin-actin cross bridges unless calcium ion is released and binds to troponin. (p. 336) |
| | A) | True |
| | B) | False |
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28 | |
Gamma motoneurons are lower motor neurons that exit the spinal cord by way of the ventral root. (p. 347) |
| | A) | True |
| | B) | False |
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29 | |
Lower motor neurons receive impulses from the upper motor neurons as well as from sensory nerve endings located in the muscles and tendons. (p. 347) |
| | A) | True |
| | B) | False |
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30 | |
Gamma motoneurons leave the spinal cord by way of the ventral root. (p. 347) |
| | A) | True |
| | B) | False |
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31 | |
Gradual stretching of a muscle activates secondary (flower-spray) sensory nerve endings more than it does the primary (annulospiral) endings. (p. 348) |
| | A) | True |
| | B) | False |
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32 | |
The CNS stimulates a muscle by either alpha or gamma neurons. It would be self-contradictory and nonfunctional to activate both alpha and gamma neurons at the same time. (p. 349) |
| | A) | True |
| | B) | False |
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33 | |
Skeletal muscles are called voluntary because they only contract in response to conscious, voluntary control from the brain. (p. 344) |
| | A) | True |
| | B) | False |
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34 | |
In the simplest spinal reflexes, nerve impulses do not have to travel through any synapses and reactions are therefore very quick. (p. 350) |
| | A) | True |
| | B) | False |
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35 | |
Damage to higher motor neurons immediately leads to spastic paralysis, in which the muscles are overly sensitive to stretch and exhibit exaggerated contractions. (p. 350) |
| | A) | True |
| | B) | False |
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36 | |
The activation of Golgi tendon organs stimulates muscle fibers to contract, thus contributing to the overall strength of the muscle response. (p. 350) |
| | A) | True |
| | B) | False |
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37 | |
The cerebellum can only inhibit skeletal muscle, not excite it. (p. 353) |
| | A) | True |
| | B) | False |
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38 | |
At the beginning of heavy exercise, the skeletal muscles seem to respire anaerobically at first, and then switch to aerobic metabolism within minutes. (p. 342) |
| | A) | True |
| | B) | False |
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39 | |
Maximal oxygen uptake (VO2 max) among world-class athletes seems to be determined more by heredity than athletic training. (p. 342) |
| | A) | True |
| | B) | False |
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40 | |
As ATP is consumed in prolonged exercise, phosphocreatine takes over the role of phosphorylating myosin cross bridges directly. (p. 344) |
| | A) | True |
| | B) | False |
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41 | |
Muscles that maintain the body's posture consist predominantly of slow-twitch fibers. (p. 345) |
| | A) | True |
| | B) | False |
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42 | |
One motor neuron may innervate dozens to thousands of muscle fibers, but all these fibers are of the same kind, fast-twitch or slow-twitch. (p. 345) |
| | A) | True |
| | B) | False |
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43 | |
Prolonged anaerobic respiration lowers the intracellular pH of muscle. (p. 346) |
| | A) | True |
| | B) | False |
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44 | |
Endurance-trained athletes produce just as much lactic acid during exercise as anyone else, but their endurance comes from the ability to metabolize it more rapidly. (p. 346) |
| | A) | True |
| | B) | False |
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45 | |
Weight training increases muscle mass by stimulating multiplication of muscle cells. (p. 346) |
| | A) | True |
| | B) | False |
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46 | |
Contraction of skeletal muscle is initiated by the binding of Ca2+ to troponin, but smooth muscle does not have troponin or use calcium in its contraction mechanism. (p. 354) |
| | A) | True |
| | B) | False |
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47 | |
Unlike skeletal muscle, smooth muscle has no sarcomeres or myosin and does not contract by the sliding filament mechanism. (p. 355) |
| | A) | True |
| | B) | False |
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2002 McGraw-Hill Higher Education