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1 | |
When a skeletal muscle contracts, it usually moves the bone at one end much more than the bone at its other end. The attachment of the muscle to the more movable bone is called its (p. 326) |
| | A) | ligament |
| | B) | insertion |
| | C) | flexor |
| | D) | origin |
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2 | |
Flexor and extensor muscles make up pairs, that together are called (p. 326) |
| | A) | antagonistic |
| | B) | agonistic |
| | C) | complementary |
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3 | |
Suppose you are sitting in the middle of a sofa and you raise both your arms to rest them stretched out along the back of the sofa. This action of the arms is known as (p. 326) |
| | A) | extension |
| | B) | abduction |
| | C) | adduction |
| | D) | flexion |
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4 | |
The fibrous connective tissue sheath which encloses a whole muscle is called the (p. 327) |
| | A) | endomysium |
| | B) | perimysium |
| | C) | epimysium |
| | D) | sarcolemma |
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5 | |
Within a muscle the fibers are divided into larger bundles called ____, each surrounded by its own connective tissue sheath. (p. 327) |
| | A) | sarcomeres |
| | B) | sarcolemmas |
| | C) | myofibers |
| | D) | fascicles |
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6 | |
The term ____ is synonymous with muscle cell. (p. 327) |
| | A) | myofiber |
| | B) | sarcomere |
| | C) | myofibril |
| | D) | fascicle |
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7 | |
Skeletal muscle cells are unusual in that they (p. 327) |
| | A) | lack smooth endoplasmic reticulum |
| | B) | have no mitochondria |
| | C) | have multiple nuclei |
| | D) | depend entirely on anaerobic respiration |
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8 | |
Skeletal muscle cells are striated that is, they have alternating dark and light bands called ____, respectively. (p. 327) |
| | A) | A and I bands |
| | B) | H and M bands |
| | C) | Z and M lines |
| | D) | I and H bands |
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9 | |
The I bands of skeletal muscle fibers each have a dark line in the middle called a (p. 327) |
| | A) | D line |
| | B) | H line |
| | C) | Z line |
| | D) | X line |
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10 | |
When the contractile behavior of a muscle is studied in vitro, this means the studies were done (p. 327) |
| | A) | with the muscle removed from the body |
| | B) | with the muscle in place in the body |
| | C) | under the microscope to observe the fibers better |
| | D) | with artificial stimulation of the muscle |
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11 | |
A muscle is stimulated and exhibits a contraction (twitch). Before this twitch is over, it is stimulated again, and a second twitch occurs "piggyback" on the first one and causes a higher contraction strength. This phenomenon is called (p. 339) |
| | A) | tetanus |
| | B) | graded contraction |
| | C) | summation |
| | D) | isometric contraction |
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12 | |
When a muscle is stimulated at such high frequency there is no visible relaxation between stimuli, the muscle is said to be in a state of (p. 340) |
| | A) | treppe |
| | B) | complete tetanus |
| | C) | isotonic contraction |
| | D) | summation |
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13 | |
If enough muscle fibers contract to make the muscle as a whole shorten in length, the muscle is said to exhibit (p. 329) |
| | A) | complete tetanus |
| | B) | graded contraction |
| | C) | isometric contraction |
| | D) | isotonic contraction |
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14 | |
The series elastic component of muscle action refers to the (p. 341) |
| | A) | necessity of numerous myofibers to contract if the muscle is to shorten |
| | B) | connection between electrical excitation of a myofiber and its contraction |
| | C) | sliding filament interaction between thick and thin filaments |
| | D) | ability of tendons to stretch and absorb some of the force of contraction |
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15 | |
A motor unit is (p. 327) |
| | A) | the motor end plate where a nerve fiber synapses with a muscle fiber |
| | B) | one motor neuron and all muscle fibers to which it leads |
| | C) | a spinal reflex arc |
| | D) | a sarcomere |
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16 | |
The contraction strength of a whole muscle varies in accordance with the (p. 330) |
| | A) | number of motor units activated |
| | B) | innervation ratio |
| | C) | amount of calcium released from the sarcoplasmic reticulum |
| | D) | amplitude of the arriving action potentials |
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17 | |
A muscle contracts because its (p. 331) |
| | A) | protein molecules get shorter |
| | B) | thick filaments get shorter |
| | C) | thin filaments slide between the thick filaments |
| | D) | tendons pull on it from opposite ends |
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18 | |
The thick filaments of a myofibril account for the (p. 331) |
| | A) | narrow dark line known as the Z line |
| | B) | dark color of the I bands |
| | C) | light color of the I bands |
| | D) | dark color of the A bands |
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19 | |
The thick filaments of muscle are composed of (p. 331) |
| | A) | tropomyosin |
| | B) | actin |
| | C) | troponin |
| | D) | myosin |
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20 | |
The basic unit of muscle contraction is the sarcomere, which is (p. 333) |
| | A) | one A band and the adjacent I band. |
| | B) | the distance from one Z line to the next. |
| | C) | equivalent to a fascicle of muscle fibers. |
| | D) | equivalent to one of the myofibrils within a muscle fiber. |
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21 | |
Which of the following does not shorten when a muscle fiber contracts? (p. 332) |
| | A) | actin filaments |
| | B) | I bands |
| | C) | sarcomeres |
| | D) | myofibrils |
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22 | |
Where are the "cross bridges" of a muscle fiber located? (p. 332) |
| | A) | in close association with the T tubules |
| | B) | midway between one A band and the next |
| | C) | in the neuromuscular cleft |
| | D) | on one end of the thick filaments |
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23 | |
At what stage of muscle contraction is ATP split into ADP and Pi? (p. 334) |
| | A) | before the cross bridges of myosin can attach to actin |
| | B) | during the power stroke when the myosin cross bridge flexes |
| | C) | at the end of the power stroke before myosin lets go of the actin filament |
| | D) | at the end of the power stroke after myosin lets go |
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24 | |
The stiffness of muscles in a corpse (rigor mortis) results from the fact that (p. 334) |
| | A) | all the neurotransmitter is used up. |
| | B) | all the calcium ion is used up. |
| | C) | thick filaments cannot let go of the thin filaments without ATP. |
| | D) | motor neurons can no longer function. |
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25 | |
The strength of a muscle's contraction is affected by all of the following factors except the (p. 340) |
| | A) | number of fibers stimulated (active motor units). |
| | B) | amplitude of the arriving action potentials. |
| | C) | initial length of the muscle before contraction. |
| | D) | thickness of the individual muscle fibers. |
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26 | |
If a muscle is already at about 60% of its resting length, it cannot be stimulated to contract any more because (p. 340) |
| | A) | there is no more ATP. |
| | B) | the myosin cross bridges cannot reach the actin filaments. |
| | C) | the Z lines abut against the thick filaments and cannot go any farther. |
| | D) | muscle fibers obey an all-or-none law. |
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27 | |
The thin filaments of a muscle fiber consist of all of the following except (p. 337) |
| | A) | tropomyosin |
| | B) | myosin |
| | C) | troponin |
| | D) | actin |
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28 | |
In order for a muscle to contract, calcium ions must bind to (p. 336) |
| | A) | actin |
| | B) | troponin |
| | C) | tropomyosin |
| | D) | myosin |
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29 | |
The calcium that binds to troponin to activate muscle contraction comes from storage sites located in the (p. 338) |
| | A) | T tubules |
| | B) | extracellular fluid |
| | C) | synaptic vesicles of the motor neuron |
| | D) | sarcoplasmic reticulum |
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30 | |
Excitation-contraction coupling refers especially to the (p. 337) |
| | A) | events at the neuromuscular junction where a motor fiber excites a muscle cell. |
| | B) | propagation of action potentials from the neuromuscular junction to the T tubules. |
| | C) | calcium release and binding to troponin molecules. |
| | D) | attachment of myosin cross bridges to the thin filaments. |
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31 | |
ATP is required by two different processes that are necessary to the contraction and relaxation of a muscle: the interaction between the thick and thin filaments of the sarcomeres, and the(p. 340) |
| | A) | binding of acetylcholine to the motor end plate. |
| | B) | release of calcium from the sarcoplasmic reticulum. |
| | C) | movement of the troponin-tropomyosin complex. |
| | D) | reuptake of calcium by the sarcoplasmic reticulum. |
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32 | |
Terminal cisternae of the sarcoplasmic reticulum receive a signal directly from the ____ which makes them release calcium ions. (p. 338) |
| | A) | motor end plate |
| | B) | sarcomeres |
| | C) | T tubules |
| | D) | motor nerve fibers |
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33 | |
The strength of a muscle's contraction is affected by all of the following factors, except the(p. 340) |
| | A) | frequency of stimulation to the muscle |
| | B) | thickness of each muscle fiber |
| | C) | amount of rest given to the muscle |
| | D) | initial length of the muscle fibers when resting |
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34 | |
Calcium ion (Ca2+) must bind to troponin for muscle contraction to occur, but for muscle relaxation to occur this Ca2+ must be removed. Where does it go? (p. 339) |
| | A) | It diffuses through the cell membrane and into the extracellular fluid. |
| | B) | It is reabsorbed by active transport into the sarcoplasmic reticulum. |
| | C) | It is taken up into the neuromuscular cleft. |
| | D) | It is bound by tropomyosin until it is needed again. |
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35 | |
As opposed to the upper motor neurons, the lower motor neurons have their cell bodies located in the (p. 347) |
| | A) | thalamus as opposed to the cerebral cortex. |
| | B) | medulla oblongata as opposed to higher brain centers. |
| | C) | spinal cord as opposed to the brain. |
| | D) | lumbar and sacral regions as opposed to cervical and thoracic. |
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36 | |
Groups of nerve fibers that cross over from the right to the left side of the spinal cord, or vice versa, are called (p. 347) |
| | A) | commissural tracts |
| | B) | ascending tracts |
| | C) | ipsilateral tracts |
| | D) | contralateral tracts |
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37 | |
The nervous system must monitor the behavior of muscles. It gets feedback information about the length of a muscle from (p. 342) |
| | A) | extrafusal fibers |
| | B) | Golgi tendon organs |
| | C) | gamma motoneurons |
| | D) | muscle spindles |
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38 | |
The sensitivity of muscle spindles to stretch can be adjusted by (p. 348) |
| | A) | further stretching of the extrafusal fibers |
| | B) | alpha motoneurons |
| | C) | gamma motoneurons |
| | D) | annulospiral nerve endings |
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39 | |
Golgi tendon organs serve to (p. 350) |
| | A) | prevent excessive stretching of contraction of a muscle. |
| | B) | enable a muscle to contract more forcibly. |
| | C) | prevent painful muscle spasms. |
| | D) | maintain muscle tone. |
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40 | |
The basal nuclei or basal ganglia normally inhibit lower motor neurons. Therefore, damage to the basal nuclei can cause (p. 353) |
| | A) | clonus |
| | B) | paraplegia |
| | C) | intention tremor |
| | D) | chorea |
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41 | |
A person continues breathing heavily for some time after exercising in order to "repay an oxygen debt". This oxygen debt includes all of the following except the oxygen that was (p. 349) |
| | A) | taken from hemoglobin in the blood. |
| | B) | taken from myoglobin in the muscle. |
| | C) | needed to replenish the store of glycogen in the muscle. |
| | D) | needed to metabolize the lactic acid produced by exercise. |
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42 | |
Sustained muscle activity may consume ATP faster than aerobic respiration can produce it. In such circumstances, ATP can be made by combining ADP with phosphate groups borrowed from (p. 344) |
| | A) | creatine kinase |
| | B) | phosphocreatine |
| | C) | cyclic AMP |
| | D) | phospholipids |
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43 | |
Slow-twitch muscle fibers differ from fast-twitch fibers in all the following ways except (p. 345) |
| | A) | they take longer to develop their maximum tension. |
| | B) | they are slower to fatigue, so they can sustain contractions longer. |
| | C) | they have a higher density of blood capillaries. |
| | D) | they contain a higher concentration of glycogen and less myoglobin. |
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44 | |
Which of the following is not a factor in muscle fatigue? (p. 346) |
| | A) | a drop in intracellular pH |
| | B) | accumulation of lactic acid |
| | C) | production of IPSPs by motor neurons |
| | D) | accumulation of extracellular K+ |
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45 | |
Intercalated discs are (p. 354) |
| | A) | gap junctions between cardiac muscle cells (fibers). |
| | B) | a unique type of motor end plate found in smooth muscle. |
| | C) | found in place of the Z lines in cardiac muscle. |
| | D) | Both a and c are correct. |
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46 | |
The Ca2+ required for contraction of smooth muscle fibers comes mainly from the (p. 355) |
| | A) | extracellular fluid surrounding the fibers. |
| | B) | cisternae of the rough endoplasmic reticulum. |
| | C) | varicosities of the autonomic nerve fibers. |
| | D) | sarcoplasmic reticulum. |
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47 | |
Single-unit (SU) smooth muscles differ from multi-unit (MU) smooth muscles in all of the following ways, except (p. 358) |
| | A) | SU muscles are myogenic and MU muscles are neurogenic. |
| | B) | SU muscle cells are joined by gap junctions, while MU cells are not. |
| | C) | MU muscles contract only in response to nervous stimulation while SU muscles can contract in response to stretch. |
| | D) | MU muscle fibers contract in unison while SU fibers contract independently of each other. |
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2002 McGraw-Hill Higher Education