Chapter 10 Review Questions

77) Cross bridge detachment is caused by ________ binding to the myosin head. A) ATP B) calcium C) magnesium D) acetylcholine E) acetylcholinesterase

A) ATP

83) Put the following events of the contraction cycle in the order in which they occur. 1. Cross-bridge detachment 2. Cross-bridge formation 3. Active site exposure 4. Myosin reactivation 5. Calcium ions bind troponin 6. Myosin head pivoting A) 5,3,6,2,1,4 B) 5,3,2,6,4,1 C) 5,3,2,6,1,4 D) 5,3,6,2,4,1 E) 3,5,2,6,1,4

C) 5,3,2,6,1,4

9) Put the following structures in order from superficial to deep. 1. muscle fiber 2. perimysium 3. myofibril 4. fascicle 5. endomysium 6. epimysium A) 1, 5, 4, 3, 2, 6 B) 6, 2, 5, 4, 1, 3 C) 6, 2, 4, 5, 1, 3 D) 1, 3, 5, 6, 4, 2 E) 2, 3, 1, 4, 6, 5

C) 6, 2, 4, 5, 1, 3

78) The sequence of processes that links the action potential to contraction is called A) neuromuscular junction. B) action potential propagation. C) excitation-contraction coupling. D) cross bridge formation. E) sliding filament theory.

C) excitation-contraction coupling.

14) Skeletal muscle fibers are formed from embryonic cells called A) sarcomeres. B) myofibrils. C) myoblasts. D) fascicles. E) myomeres.

C) myoblasts.

21) The region of the sarcomere containing the thick filaments is the A) Z line. B) M line. C) H band. D) A band. E) I band.

D) A band.

94) A muscle produces its highest tension when in complete A) recovery. B) treppe. C) wave summation. D) aerobic metabolism. E) tetanus.

E) tetanus.

57) In the myofibril the protein that possesses the active site for myosin heads to bind is called A) titin. B) actin. C) G actin. D) nebulin. E) myosin. -Tropomyosin

-Tropomyosin

82) Put the following events of the neuromuscular junction in the order in which they occur. 1. Action potential is propagated in the sarcolemma. 2. Acetylcholine binds to ligand gated sodium channels. 3. Action potential arrives at the neuromuscular junction. 4. Vesicles full of acetylcholine are stored at the axon terminal. 5. Acetylcholine is released into the synaptic cleft. A) 4,3,5,2,1 B) 4,3,5,1,2 C) 4,5,3,2,1 D) 4,3,1,5,2 E) 4,1,3,2,5

A) 4,3,5,2,1

105) Identify the incorrect statement about a single motor unit. A) The more neurons involved, the more powerful the contraction. B) The smaller the number of muscle fibers, the more precise the movement. C) Fine motor skills depend on the development of small motor units. D) Some motor units include as many as 2000 muscle fibers. E) Muscle fibers of one motor unit intermingle with the fibers of another motor unit.

A) The more neurons involved, the more powerful the contraction.

125) Which of the following is not characteristic of smooth muscle? A) The striations are due to the orderly arrangement of actin and myosin. B) Neurons that innervate smooth muscles are under involuntary control. C) Smooth muscle cells are uninucleate. D) Smooth muscles do not contain sarcomeres. E) The thin filaments of smooth muscle fibers are attached to dense bodies.

A) The striations are due to the orderly arrangement of actin and myosin.

66) Triggering of the muscle action potential occurs after A) acetylcholine binds to chemically-gated channels in the motor end plate. B) acetylcholinesterase is released from synaptic vesicles into the synaptic cleft. C) calcium ion binds to channels on the motor end plate. D) the action potential jumps across the neuromuscular junction. E) Any of these can produce an action potential in the muscle cell.

A) acetylcholine binds to chemically-gated channels in the motor end plate.

49) Thin filaments are mostly made of the protein A) actin. B) titin. C) myosin. D) tropomyosin. E) nebulin.

A) actin.

47) The protein that is found in the Z line of a sarcomere is called A) actinin. B) titin. C) nebulin. D) myosin. E) actin.

A) actinin

96) The point in a muscle twitch when the troponin is bound to calcium is called the A) contraction phase. B) relaxation phase. C) stimulus phase. D) latent period. E) isotonic period.

A) contraction phase.

5) Nerves and blood vessels that service a muscle fiber are located in the connective tissues of its A) endomysium. B) perimysium. C) sarcolemma. D) sarcomere. E) myofibrils.

A) endomysium.

7) The delicate connective tissue that surrounds the skeletal muscle fibers and ties adjacent muscle fibers together is the A) endomysium. B) perimysium. C) epimysium. D) superficial fascia. E) periosteum.

A) endomysium.

119) Muscles that move the eyeball have ________ fibers. A) fast B) slow C) intermediate D) circular E) All of the answers are correct.

A) fast

6) A fascicle is a A) group of muscle fibers that are encased in the perimysium. B) layer of connective tissue that separates muscle from skin. C) group of muscle fibers that are all part of the same motor unit. D) group of muscle fibers and motor neurons. E) collection of myofibrils in a muscle fiber.

A) group of muscle fibers that are encased in the perimysium.

86) A muscle producing almost peak tension during rapid cycles of contraction and relaxation is said to be in A) incomplete tetanus. B) complete tetanus. C) treppe. D) wave summation. E) recruitment.

A) incomplete tetanus.

116) Heat energy gained from muscle contraction is released by the ________ system. A) integumentary B) respiratory C) cardiovascular D) urinary E) endocrine

A) integumentary

104) In an isotonic contraction, A) muscle tension exceeds the load and the muscle lifts the load. B) tension rises and falls but the muscle length is constant. C) the peak tension is less than the load. D) many twitches always fuse into one. E) postural muscles stabilize the vertebrae.

A) muscle tension exceeds the load and the muscle lifts the load.

16) The plasma membrane of a skeletal muscle fiber is called the A) sarcolemma. B) sarcomere. C) sarcosome. D) sarcoplasmic reticulum. E) sarcoplasm.

A) sarcolemma.

28) The series of membranous channels that surround each myofibril is the A) sarcoplasmic reticulum. B) sarcoplasm. C) sarcomere. D) sarcolemma. E) endomysium.

A) sarcoplasmic reticulum.

53) The structural theory that explains how a muscle fiber contracts is called the ________ theory. A) sliding filament B) excitation-contraction coupling C) neuromuscular D) muscle contraction E) action-myosin interaction

A) sliding filament

3) At each end of the muscle, the collagen fibers of the epimysium, perimysium, and endomysium, come together to form a A) tendon. B) satellite cell. C) ligament. D) tenosynovium. E) sheath.

A) tendon.

62) Which of the following become connected by myosin cross-bridges during muscle contraction? A) thin filaments and thick filaments B) thick filaments and titin filaments C) z disks and actin filaments D) thick filaments and t-tubules E) thin filaments and t-tubules

A) thin filaments and thick filaments

55) In the sarcomere which elastic protein attaches the thick filament to the Z line? A) titin B) actin C) G actin D) nebulin E) myosin

A) titin

45) When calcium ion binds to troponin, A) tropomyosin rolls away from the active site. B) active sites on the myosin are exposed. C) actin heads will bind to myosin. D) muscle relaxation occurs. E) myosin shortens.

A) tropomyosin rolls away from the active site.

25) Each thin filament consists of A) two actin protein strands coiled helically around each other. B) chains of myosin molecules. C) six molecules coiled into a helical structure. D) a rod-shaped structure with "heads" projecting from each end. E) a double strand of myosin molecules.

A) two actin protein strands coiled helically around each other.

65) In a sarcomere, cross-bridge attachment occurs specifically in the A) zone of overlap. B) A band. C) I band. D) M line. E) H band.

A) zone of overlap.

81) Put the following events of excitation-contraction coupling in the order in which they occur. 1. Excitation 2. Sarcomere shortening 3. Generation of muscle tension 4. Neural control 5. Contraction cycle begins 6. Release of calcium ions A) 4,1,5,2,6,3 B) 4,1,6,5,2,3 C) 1,2,5,6,3,4 D) 6,1,4,2,5,3 E) 1,4,6,2,5,3

B) 4,1,6,5,2,3

54) The region of sarcomere where thin and thick filaments are located is called the A) I band. B) A band. C) Z line. D) M line. E) zone of overlap.

B) A band.

12) In a sarcomere, the central portion of thick filaments are linked laterally by proteins of the A) Z line. B) M line. C) H band. D) A band. E) I band.

B) M line.

120) Which of the following statements is/are false regarding human muscles? A) Most have both slow and fast fibers. B) Slow fibers are abundant in the muscles of the hand. C) Eye muscles are composed entirely of fast fibers. D) Slow fibers are abundant in the back muscles. E) All of the answers are correct; none of them are true regarding human muscles.

B) Slow fibers are abundant in the muscles of the hand.

22) The skeletal muscle complex known as the triad consists of A) actin, myosin, and titin filaments. B) a transverse tubule and two terminal cisternae. C) filaments, myofibrils, and sarcomeres. D) A bands, H bands, and I bands. E) actin, myosin, and sarcomeres.

B) a transverse tubule and two terminal cisternae.

44) The most important factor in decreasing the intracellular concentration of calcium ion after contraction is A) active transport of calcium across the sarcolemma. B) active transport of calcium into the sarcoplasmic reticulum. C) active transport of calcium into the synaptic cleft. D) diffusion of calcium out of the cell. E) diffusion of calcium into the sarcoplasmic reticulum.

B) active transport of calcium into the sarcoplasmic reticulum.

85) When a muscle is stimulated repeatedly at a high rate, the amount of tension gradually increases to a steady maximum tension. This state of maximum tension is called A) incomplete tetanus. B) complete tetanus. C) a twitch. D) wave summation. E) recruitment.

B) complete tetanus.

1) Muscle tissue, one of the four basic tissue groups, consists chiefly of cells that are highly specialized for A) conduction. B) contraction. C) peristalsis. D) cushioning. E) secretion.

B) contraction

46) Physical evidence that supports the sliding filament theory of muscle contraction includes A) constant distance between Z lines during contraction. B) decreased width of the H band during contraction. C) increased width of the I band during contraction. D) decreased width of the A band during contraction. E) the I band + H band distance is constant during contraction.

B) decreased width of the H band during contraction.

4) The dense layer of connective tissue that surrounds an entire skeletal muscle is the A) tendon. B) epimysium. C) endomysium. D) perimysium. E) fascicle.

B) epimysium.

18) Muscle fibers differ from "typical cells" in that muscle fibers A) lack a plasma membrane. B) have many nuclei. C) are very small. D) lack mitochondria. E) have large gaps in the cell membrane.

B) have many nuclei.

107) The type of contraction where the tension is less than the load is called A) isometric contraction. B) isotonic eccentric contraction. C) isotonic concentric contraction. D) isometric concentric contraction. E) isometric eccentric contraction.

B) isotonic eccentric contraction.

97) Detachment of myosin cross-bridges occurs during the A) contraction phase. B) relaxation phase. C) stimulus phase. D) latent period. E) isotonic period.

B) relaxation phase.

17) Which of the following best describes the term sarcomere? A) protein that accounts for elasticity of resting muscle B) repeating unit of striated myofibrils C) storage site for calcium ions D) thin filaments are anchored here E) largely made of myosin molecules

B) repeating unit of striated myofibrils

15) The repeating unit of a skeletal muscle fiber is the A) sarcolemma. B) sarcomere. C) sarcoplasmic reticulum. D) myofibril. E) myofilament.

B) sarcomere.

51) Stem cells located between the endomysium and sarcolemma that function in the repair of damaged muscle tissue are called A) myocytes. B) satellite cells. C) endocytes. D) sarcocytes. E) creatinocytes.

B) satellite cells.

31) Since each myofibril is attached at either end of the muscle fiber, when sarcomeres shorten, the muscle fiber A) lengthens. B) shortens. C) strengthens. D) weakens. E) pulls from the middle.

B) shortens.

117) The type of muscle fiber that is most resistant to fatigue is the ________ fiber. A) fast B) slow C) intermediate D) anaerobic E) high-density

B) slow

8) The bundle of collagen fibers at the end of a skeletal muscle that attaches the muscle to bone is called a(n) A) fascicle. B) tendon. C) ligament. D) epimysium. E) myofibril.

B) tendon.

52) The complex of a transverse tubule and two adjacent terminal cisternae is known as a A) trimer. B) triad. C) triptych. D) trisome. E) trilogy.

B) triad.

93) A single contraction-relaxation cycle in a muscle fiber produces a(n) A) cramp. B) twitch. C) tetanic contraction. D) action potential. E) motor unit.

B) twitch.

30) When a skeletal muscle fiber contracts, the A) H bands and I bands get larger. B) zones of overlap get larger. C) Z lines move further apart. D) width of the A band increases. E) All of the answers are correct.

B) zones of overlap get larger.

56) In the sarcomere the protein that forms two twisted strands around a central rod-like protein is called A) titin. B) actin. C) G actin. D) nebulin. E) myosin.

C) G actin.

23) The area in the center of the A band that contains no thin filaments is the A) Z line. B) M line. C) H band. D) I band. E) zone of overlap.

C) H band.

115) How would an elevated level of thyroid hormone in the body affect skeletal muscles? A) It would stimulate atrophy. B) It would stimulate hypertrophy. C) It would stimulate energy use and heat production. D) It would decrease heat production by muscle tissue. E) It would cause an increase in muscle mass.

C) It would stimulate energy use and heat production.

70) The cytoplasm of the neuromuscular terminal contains vesicles filled with molecules of the neurotransmitter A) epinephrine. B) norepinephrine. C) acetylcholine. D) antidiuretic hormone. E) adrenaline.

C) acetylcholine.

110) Creatine phosphate A) is produced by the process of anaerobic respiration. B) can replace ATP in binding to myosin molecules during contraction. C) acts as an energy reserve in muscle tissue. D) is only formed during strenuous exercise. E) cannot transfer its phosphate group to ADP.

C) acts as an energy reserve in muscle tissue.

109) A resting muscle generates most of its ATP by A) hydrolysis of creatine phosphate. B) anaerobic respiration. C) aerobic metabolism of fatty acids. D) glycogenolysis. E) the tricarboxylic acid cycle.

C) aerobic metabolism of fatty acids.

10) A(n) ________ can be described as a broad tendinous sheet. A) fasciae B) retinaculum C) aponeurosis D) interstitium E) tympanum

C) aponeurosis

42) Active sites on the actin become available for binding after A) actin binds to troponin. B) troponin binds to tropomyosin. C) calcium binds to troponin. D) calcium binds to tropomyosin. E) myosin binds to troponin.

C) calcium binds to troponin.

71) At what point during excitation contraction coupling does exocytosis play a role? A) during calcium ion reuptake into the sarcoplasmic reticulum B) when sodium channels open up on the motor end plate C) during acetylcholine release from the synaptic terminal D) when the action potential surges through the T-tubules E) when ATP splits into ADP and P on the free myosin head

C) during acetylcholine release from the synaptic terminal

73) Synaptic vesicles contain neurotransmitters that are released by ________ when the action potential arrives. A) endocytosis B) apoptosis C) exocytosis D) hydrolysis E) sodium

C) exocytosis

121) Large-diameter, densely packed myofibrils, large glycogen reserves, and few mitochondria are characteristics of A) slow fibers. B) intermediate fibers. C) fast fibers. D) red muscles. E) fatty muscles.

C) fast fibers.

126) Which of the following is not a function of smooth muscle tissue? A) altering the diameter of the respiratory passageways B) elevating hairs on the arm C) forcing blood from the heart into the major arteries D) moving food materials along the digestive tract E) forcing urine out of the urinary tract

C) forcing blood from the heart into the major arteries

106) The type of contraction where the tension exceeds the load is called A) isometric contraction. B) isotonic eccentric contraction. C) isotonic concentric contraction. D) isometric concentric contraction. E) isometric eccentric contraction.

C) isotonic concentric contraction.

98) A single motor neuron together with all the muscle fibers it innervates is called a(n) A) end foot. B) end plate. C) motor unit. D) dermatome. E) myotome.

C) motor unit.

11) Interactions between actin and myosin filaments of the sarcomere are responsible for A) muscle fatigue. B) the conduction of neural stimulation to the muscle fiber. C) muscle contraction. D) muscle relaxation. E) the striped appearance of skeletal muscle.

C) muscle contraction.

113) During the recovery period following exercise, all of the following are true except A) lactic acid is removed from muscle cells. B) the muscle actively produces ATP. C) muscle fibers are unable to contract. D) oxygen is consumed at above the resting rate. E) heat is generated.

C) muscle fibers are unable to contract.

103) In which of the following would the motor units have the fewest muscle fibers? A) muscles of the neck B) postural muscles of the back C) muscles that control the eyes D) thigh muscles E) calf muscles

C) muscles that control the eyes

50) Thick filaments are made of the protein A) actin. B) titin. C) myosin. D) tropomyosin. E) nebulin.

C) myosin.

60) Each skeletal muscle fiber is controlled by a motor neuron at a single A) synaptic knob. B) sarcomere. C) neuromuscular junction. D) synaptic cleft. E) transverse tubule.

C) neuromuscular junction.

19) Which of the following best describes the term sarcoplasmic reticulum? A) protein that accounts for elasticity of resting muscle B) repeating unit of striated myofibrils C) storage and release site for calcium ions D) thin filaments are anchored here E) largely made of myosin molecules

C) storage and release site for calcium ions

114) Which of the following hormones directly stimulates growth of muscle tissue, leading to increased muscle mass? A) epinephrine B) thyroid hormone C) testosterone D) parathyroid hormone E) calcitonin

C) testosterone

43) The action potential is conducted into a skeletal muscle fiber by A) motor end plates. B) neuromuscular junctions. C) transverse tubules. D) triads. E) sarcoplasmic reticulum.

C) transverse tubules.

27) At rest, active sites on the actin are blocked by A) myosin molecules. B) troponin molecules. C) tropomyosin molecules. D) calcium ions. E) ATP molecules.

C) tropomyosin molecules.

24) At rest, the tropomyosin molecule is held in place by A) actin molecules. B) myosin molecules. C) troponin molecules. D) ATP molecules. E) calcium ions.

C) troponin molecules.

84) The rapid rise and fall in force produced by a muscle fiber after a single action potential is a(n) A) tetanus. B) unfused tetanus. C) twitch. D) motor end plate potential. E) muscle action potential.

C) twitch.

67) The following is a list of the events that occur during a muscle contraction. What is the correct sequence of these events? 1. Myosin cross-bridges bind to the actin. 2. The free myosin head splits ATP. 3. Calcium ion is released from the sarcoplasmic reticulum. 4. The myosin head pivots toward the center of the sarcomere. 5. Calcium ion binds to troponin. 6. The myosin head binds an ATP molecule and detaches from the actin. A) 1, 3, 5, 4, 6, 2 B) 5, 1, 4, 6, 2, 3 C) 3, 5, 1, 2, 4, 6 D) 3, 5, 1, 4, 6, 2 E) 1, 4, 6, 2, 3, 5

D) 3, 5, 1, 4, 6, 2

112) Aerobic metabolism normally provides ________ percent of the ATP demands of a resting muscle cell. A) 25 B) 50 C) 70 D) 95 E) 100

D) 95

127) Which of the following is true about the difference between cardiac muscle cells and skeletal muscle cells? A) Cardiac muscle cells does not have striations like skeletal muscle cells. B) Cardiac muscle cells does not have t-tubules. C) Cardiac muscle cells does not have sarcomeres. D) Cardiac muscle cells have intercalated discs where skeletal muscle cells do not. E) Cardiac muscle cells have more nuclei in them than skeletal muscle cells.

D) Cardiac muscle cells have intercalated discs where skeletal muscle cells do not.

80) Which of the following is not true of acetylcholine? A) It binds to receptor membrane channels. B) It diffuses across the synaptic cleft. C) It is stored in the neuron in vesicles. D) It enters the muscle fiber to release calcium form the sarcoplasmic reticulum. E) It is digested by acetylcholinesterase.

D) It enters the muscle fiber to release calcium form the sarcoplasmic reticulum.

59) In response to action potentials arriving along the transverse tubules, the sarcoplasmic reticulum releases A) acetylcholine. B) sodium ions. C) potassium ions. D) calcium ions. E) hydrogen ions.

D) calcium ions.

95) During the time when the action potential moves through the sarcolemma a muscle twitch is in A) contraction phase. B) relaxation phase. C) stimulus phase. D) latent period. E) isotonic period.

D) latent period.

58) In the myofibril the thin filament is organized around a rod-like core protein called A) titin. B) actin. C) G actin. D) nebulin. E) myosin.

D) nebulin.

124) The ability of smooth muscle to function over a wide range of lengths is called A) elasticity. B) contractility. C) extensibility. D) plasticity. E) variability.

D) plasticity.

13) The advantage of having many nuclei in a skeletal muscle fiber is the ability to A) contract much more forcefully. B) produce more ATP with little oxygen. C) store extra DNA for metabolism. D) produce large amounts of muscle proteins. E) produce nutrients for muscle contraction.

D) produce large amounts of muscle proteins.

122) Which of the following types of muscle fibers are best adapted for prolonged contraction such as standing all day? A) uninucleated fibers B) striated fibers C) fast fibers D) slow fibers E) intermediate fibers

D) slow fibers

61) The narrow space between the synaptic terminal and the muscle fiber is the A) synaptic knob. B) motor end plate. C) motor unit. D) synaptic cleft. E) M line.

D) synaptic cleft.

20) Which of the following best describes the term Z line? A) protein that accounts for elasticity of resting muscle B) repeating unit of striated myofibrils C) storage site for calcium ions D) thin filaments are anchored here E) largely made of myosin molecules

D) thin filaments are anchored here

29) All of the following proteins are part of the thin filaments except A) actin. B) tropomyosin. C) troponin. D) titin. E) None of the answers is correct; there are no exceptions.

D) titin.

48) The protein that regulates muscle contraction by controlling the availability of active sites on actin is called A) actin. B) titin. C) myosin. D) tropomyosin. E) nebulin.

D) tropomyosin.

76) Active sites become exposed when calcium ions bind to A) tropomyosin. B) actin. C) myosin. D) troponin. E) calcium channels.

D) troponin.

87) If a second stimulus arrives before the relaxation phase has ended, a second, more powerful contraction occurs. This addition of one twitch to another is called A) incomplete tetanus. B) complete tetanus. C) treppe. D) wave summation. E) recruitment.

D) wave summation.

111) During anaerobic glycolysis, A) ATP is produced. B) pyruvic acid is produced. C) oxygen is not consumed. D) carbohydrate is metabolized. E) All of the answers are correct.

E) All of the answers are correct.

2) Which of the following is a recognized function of skeletal muscle? A) produce movement B) maintain posture C) maintain body temperature D) guard body entrances and exits E) All of the answers are correct.

E) All of the answers are correct.

26) The region of the sarcomere that always contains thin filaments is the A) Z line. B) M line. C) H band. D) A band. E) I band.

E) I band.

79) The role of acetylcholinesterase is to A) bind to ligand gated sodium channels. B) activate acetylcholine. C) release acetylcholine into the synaptic cleft. D) transport acetylcholine across the synaptic cleft. E) break down acetylcholine into acetate and choline components.

E) break down acetylcholine into acetate and choline components.

108) Which of the following allows muscles to return to their original shape during relaxation? A) gravity B) opposing muscle contractions C) elastic forces D) myosin binding E) gravity, opposing muscle contractions, and elastic forces

E) gravity, opposing muscle contractions, and elastic forces

118) Fast fibers A) have low resistance to fatigue. B) rely on aerobic metabolism. C) have many mitochondria. D) have twitches with a very brief contraction phase. E) have low resistance to fatigue and quick twitches.

E) have low resistance to fatigue and quick twitches.

100) The type of contraction in which the muscle fibers do not shorten is called A) tetany. B) treppe. C) concentric. D) isotonic. E) isometric.

E) isometric.

75) Communication between axons and muscle fibers occurs at specialized synapses called A) nervous units. B) synaptic terminals. C) motor end plates. D) motor units. E) neuromuscular junctions.

E) neuromuscular junctions.

99) The increase in muscle tension that is produced by increasing the number of active motor units is called A) incomplete tetanus. B) complete tetanus. C) treppe. D) wave summation. E) recruitment.

E) recruitment.