5) Nerves and blood vessels that service a muscle fiber are located in the connective tissues of its

1. A) endomysium.
2. B) perimysium.
3. C) sarcolemma.
4. D) sarcomere.
5. E) myofibrils

A) endomysium

6) A fascicle is a

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

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

7) The delicate connective tissue that surrounds the skeletal muscle fibers and ties adjacent muscle fibers together is the

1. A) endomysium.
2. B) perimysium.
3. C) epimysium.
4. D) superficial fascia.
5. E) periosteum.

A) endomysium

8) The bundle of collagen fibers at the end of a skeletal muscle that attaches the muscle to bone is called a(n)

1. A) fascicle.
2. B) tendon.
3. C) ligament.
4. D) epimysium.
5. E) myofibril

B) tendon

9) Put the following structures in order from superficial to deep.

1. muscle fiber
2. perimysium
3. myofibril
4. fascicle
5. endomysium
6. epimysium
7. A) 1, 5, 4, 3, 2, 6
8. B) 6, 2, 5, 4, 1, 3
9. C) 6, 2, 4, 5, 1, 3
10. D) 1, 3, 5, 6, 4, 2
11. E) 2, 3, 1, 4, 6, 5

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

10) Interactions between actin and myosin filaments of the sarcomere are responsible for

1. A) muscle fatigue.
2. B) the conduction of neural stimulation to the muscle fiber.
3. C) muscle contraction.
4. D) muscle relaxation.
5. E) the striped appearance of skeletal muscle

C) muscle contraction

11) In a sarcomere, the central portion of thick filaments are linked laterally by proteins of the

1. A) Z line.
2. B) M line.
3. C) H band.
4. D) A band.
5. E) I band

B) M line

12) The advantage of having many nuclei in a skeletal muscle fiber is the ability to

1. A) contract much more forcefully.
2. B) produce more ATP with little oxygen.
3. C) store extra DNA for metabolism.
4. D) produce large amounts of muscle proteins.
5. E) produce nutrients for muscle contraction

D) produce large amounts of muscle proteins

13) Skeletal muscle fibers are formed from embryonic cells called

1. A) sarcomeres.
2. B) myofibrils.
3. C) myoblasts.
4. D) fascicles.
5. E) myomeres

C) myoblasts

14) The repeating unit of a skeletal muscle fiber is the

1. A) sarcolemma.
2. B) sarcomere.
3. C) sarcoplasmic reticulum.
4. D) myofibril.
5. E) myofilament

B) sarcomere

15) The plasma membrane of a skeletal muscle fiber is called the

1. A) sarcolemma.
2. B) sarcomere.
3. C) sarcosome.
4. D) sarcoplasmic reticulum.
5. E) sarcoplasm.

A) sarcolemma

16) Which of the following best describes the term sarcomere?

1. A) protein that accounts for elasticity of resting muscle
2. B) repeating unit of striated myofibrils
3. C) storage site for calcium ions
4. D) thin filaments are anchored here
5. E) largely made of myosin molecules

B) repeating unit of striated myofibrils

17) Muscle fibers differ from "typical cells" in that muscle fibers

1. A) lack a plasma membrane.
2. B) have many nuclei.
3. C) are very small.
4. D) lack mitochondria.
5. E) have large gaps in the cell membrane

B) have many nuclei

18) Which of the following best describes the term sarcoplasmic reticulum?

1. A) protein that accounts for elasticity of resting muscle
2. B) repeating unit of striated myofibrils
3. C) storage and release site for calcium ions
4. D) thin filaments are anchored here
5. E) largely made of myosin molecules

C) storage and release site for calcium ions

19) Which of the following best describes the term Z line?

1. A) protein that accounts for elasticity of resting muscle
2. B) repeating unit of striated myofibrils
3. C) storage site for calcium ions
4. D) thin filaments are anchored here
5. E) largely made of myosin molecules

D) thin filaments are anchored here

20) The region of the sarcomere containing the thick filaments is the

1. A) Z line.
2. B) M line.
3. C) H band.
4. D) A band.
5. E) I band.

D) A band

21) The skeletal muscle complex known as the triad consists of

1. A) actin, myosin, and titin filaments.
2. B) a transverse tubule and two terminal cisternae.
3. C) filaments, myofibrils, and sarcomeres.
4. D) A bands, H bands, and I bands.
5. E) actin, myosin, and sarcomeres.

B) a transverse tubule and two terminal cisternae.

22) Cross-bridges are portions of

1. A) actin molecules.
2. B) myosin molecules.
3. C) troponin molecules.
4. D) tropomyosin molecules.
5. E) calcium ions.

B) myosin molecules

23) The area in the center of the A band that contains no thin filaments is the

1. A) Z line.
2. B) M line.
3. C) H band.
4. D) I band.
5. E) zone of overlap

C) H band

24) Each skeletal muscle fiber contains ________ myofibrils.

1. A) 50 to 100
2. B) 100 to 150
3. C) 150 to 200
4. D) 200 to 500
5. E) hundreds to thousands

E) hundreds to thousands

25) At rest, the tropomyosin molecule is held in place by

1. A) actin molecules.
2. B) myosin molecules.
3. C) troponin molecules.
4. D) ATP molecules.
5. E) calcium ions

C) troponin molecules

26) Each thin filament consists of

1. A) two actin protein strands coiled helically around each other.
2. B) chains of myosin molecules.
3. C) six molecules coiled into a helical structure.
4. D) a rod-shaped structure with "heads" projecting from each end.
5. E) a double strand of myosin molecules

A) two actin protein strands coiled helically around each other

27) Which of the following best describes the term titin?

1. A) protein that accounts for elasticity of resting muscle
2. B) repeating unit of striated myofibrils
3. C) storage and release site for calcium ions
4. D) thin filaments are anchored here
5. E) largely made of myosin molecules

A) protein that accounts for elasticity of resting muscle

28) The region of the sarcomere that always contains thin filaments is the

1. A) Z line.
2. B) M line.
3. C) H band.
4. D) A band.
5. E) I band.

E) I band

29) At rest, active sites on the actin are blocked by

1. A) myosin molecules.
2. B) troponin molecules.
3. C) tropomyosin molecules.
4. D) calcium ions.
5. E) ATP molecules.

C) tropomyosin molecules

30) The series of membranous channels that surround each myofibril is the

1. A) sarcoplasmic reticulum.
2. B) sarcoplasm.
3. C) sarcomere.
4. D) sarcolemma.
5. E) endomysium

A) sarcoplasmic reticulum

31) Which of the following statements about the microscopic anatomy of skeletal muscle fibers is false?

1. A) Tubular extensions of the sarcolemma penetrate the fiber transversely.
2. B) Cross striations result from the lateral alignment of thick and thin filaments.
3. C) Each fiber has many nuclei to ensure adequate muscle protein production.
4. D) The net-like sarcoplasmic reticulum surrounds each myofilament.
5. E) All of the answers are true; there are no false answers.

D) The net-like sarcoplasmic reticulum surrounds each myofilament

32) All of the following proteins are part of the thin filaments except

1. A) actin.
2. B) tropomyosin.
3. C) troponin.
4. D) titin.
5. E) None of the answers is correct; there are no exceptions

D) titin

33) When a skeletal muscle fiber contracts, the

1. A) H bands and I bands get larger.
2. B) zones of overlap get larger.
3. C) Z lines move further apart.
4. D) width of the A band increases.
5. E) All of the answers are correct.

B) zones of overlap get larger.

34) Since each myofibril is attached at either end of the muscle fiber, when sarcomeres shorten, the muscle fiber

1. A) lengthens.
2. B) shortens.
3. C) strengthens.
4. D) weakens.
5. E) pulls from the middle.

B) shortens

45) In response to action potentials arriving along the transverse tubules, the sarcoplasmic reticulum releases

1. A) acetylcholine.
2. B) sodium ions.
3. C) potassium ions.
4. D) calcium ions.
5. E) hydrogen ions

D) calcium ions

46) Each skeletal muscle fiber is controlled by a motor neuron at a single

1. A) synaptic knob.
2. B) sarcomere.
3. C) neuromuscular junction.
4. D) synaptic cleft.
5. E) transverse tubule.

C) neuromuscular junction

47) The narrow space between the synaptic terminal and the muscle fiber is the

1. A) synaptic knob.
2. B) motor end plate.
3. C) motor unit.
4. D) synaptic cleft.
5. E) M line.

D) synaptic cleft

48) Active sites on the actin become available for binding after

1. A) actin binds to troponin.
2. B) troponin binds to tropomyosin.
3. C) calcium binds to troponin.
4. D) calcium binds to tropomyosin.
5. E) myosin binds to troponin

C) calcium binds to troponin

49) Receptors for acetylcholine are located on the

1. A) synaptic knob.
2. B) motor end plate.
3. C) sarcomere.
4. D) synaptic cleft.
5. E) transverse tubule.

B) motor end plate.

50) The action potential is conducted into a skeletal muscle fiber by

1. A) motor end plates.
2. B) neuromuscular junctions.
3. C) transverse tubules.
4. D) triads.
5. E) sarcoplasmic reticulum

C) transverse tubules

51) The most important factor in decreasing the intracellular concentration of calcium ion after contraction is

1. A) active transport of calcium across the sarcolemma.
2. B) active transport of calcium into the sarcoplasmic reticulum.
3. C) active transport of calcium into the synaptic cleft.
4. D) diffusion of calcium out of the cell.
5. E) diffusion of calcium into the sarcoplasmic reticulum.

B) active transport of calcium into the sarcoplasmic reticulum

52) Which of the following acts as an ATPase during the contraction cycle of muscle?

1. A) actin molecules
2. B) troponin molecules
3. C) tropomyosin molecules
4. D) the head portion of the myosin molecule
5. E) the tail portion of the myosin molecule

D) the head portion of the myosin molecule

53) When calcium ion binds to troponin,

1. A) tropomyosin rolls away from the active site.
2. B) active sites on the myosin are exposed.
3. C) actin heads will bind to myosin.
4. D) muscle relaxation occurs.
5. E) myosin shortens

A) tropomyosin rolls away from the active site

54) Which of the following become connected by myosin cross-bridges during muscle contraction?

1. A) thin filaments and thick filaments
2. B) thick filaments and titin filaments
3. C) z disks and actin filaments
4. D) thick filaments and t-tubules
5. E) thin filaments and t-tubules

A) thin filaments and thick filaments

55) After death, muscle fibers run out of ATP and calcium begins to leak from the sarcoplasmic reticulum into the sarcoplasm. This results in a condition known as

1. A) tetany.
2. B) treppe.
3. C) depolarization.
4. D) rigor mortis.
5. E) oxygen debt

D) rigor mortis

56) In rigor mortis

1. A) the myosin heads are attached to actin.
2. B) ATP is depleted.
3. C) calcium ions keep binding to troponin.
4. D) sustained contractions occur.
5. E) All of the answers are correct

E) All of the answers are correct

57) In a sarcomere, cross-bridge attachment occurs specifically in the

1. A) zone of overlap.
2. B) A band.
3. C) I band.
4. D) M line.
5. E) H band

A) zone of overlap

58) Physical evidence that supports the sliding filament theory of muscle contraction includes

1. A) constant distance between Z lines during contraction.
2. B) decreased width of the H band during contraction.
3. C) increased width of the I band during contraction.
4. D) decreased width of the A band during contraction.
5. E) the I band + H band distance is constant during contraction

B) decreased width of the H band during contraction

59) Triggering of the muscle action potential occurs after

1. A) acetylcholine binds to chemically-gated channels in the motor end plate.
2. B) acetylcholinesterase is released from synaptic vesicles into the synaptic cleft.
3. C) calcium ion binds to channels on the motor end plate.
4. D) the action potential jumps across the neuromuscular junction.
5. 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.

60) 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.
7. A) 1, 3, 5, 4, 6, 2
8. B) 5, 1, 4, 6, 2, 3
9. C) 3, 5, 1, 2, 4, 6
10. D) 3, 5, 1, 4, 6, 2
11. E) 1, 4, 6, 2, 3, 5

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

61) How would the loss of acetylcholinesterase from the motor end plate affect skeletal muscle?

1. A) It would make the muscles less excitable.
2. B) It would produce muscle weakness.
3. C) It would cause muscles to stay contracted.
4. D) It would cause muscles to stay relaxed.

E) It would have little effect on skeletal muscles

C) It would cause muscles to stay contracted

62) When acetylcholine binds to receptors at the motor end plate, the sarcolemma becomes

1. A) more permeable to sodium ions.
2. B) less permeable to sodium ions.
3. C) more permeable to calcium ions.
4. D) less permeable to potassium ions.
5. E) less permeable to potassium and sodium ions

A) more permeable to sodium ions

63) The cytoplasm of the neuromuscular terminal contains vesicles filled with molecules of the neurotransmitter

1. A) epinephrine.
2. B) norepinephrine.
3. C) acetylcholine.
4. D) antidiuretic hormone.
5. E) adrenaline.

C) acetylcholine

64) At what point during excitation contraction coupling does exocytosis play a role?

1. A) during calcium ion reuptake into the sarcoplasmic reticulum
2. B) when sodium channels open up on the motor end plate
3. C) during acetylcholine release from the synaptic terminal
4. D) when the action potential surges through the T-tubules
5. E) when ATP splits into ADP and P on the free myosin head

C) during acetylcholine release from the synaptic terminal

65) Which of the following statements about excitation-contraction coupling is incorrect?

1. A) Calcium ions travel through the transverse tubule.
2. B) Calcium ion is released from the sarcoplasmic reticulum.
3. C) Tropomyosin moves to expose myosin binding sites on actin.
4. D) Troponin binds calcium ion and signals tropomyosin to move.
5. E) Relaxation requires uptake of calcium ion by the sarcoplasmic reticulum.

A) Calcium ions travel through the transverse tubule

66) Synaptic vesicles contain neurotransmitters that are released by ________ when the action potential arrives.

1. A) endocytosis
2. B) apoptosis
3. C) exocytosis
4. D) hydrolysis
5. E) sodium

C) exocytosis

67) The muscle weakness of myasthenia gravis results from

1. A) insufficient acetylcholine release from presynaptic vesicles.
2. B) loss of acetylcholine receptors in the end-plate membrane.
3. C) the motor neuron action potential being too small to stimulate the muscle fibers.
4. D) excessive acetylcholinesterase that destroys the neurotransmitter.
5. E) inability of the muscle fiber to produce ATP

B) loss of acetylcholine receptors in the end-plate membrane

68) A patient takes a medication that blocks ACh receptors of skeletal muscle fibers. What is this drug's effect on skeletal muscle contraction?

1. A) increases tone in the muscle
2. B) causes a strong contraction similar to a "charlie horse" cramp
3. C) increases the muscle's excitability
4. D) produces a strong, continuous state of contraction
5. E) reduces the muscle's ability for contraction

E) reduces the muscle's ability for contraction

69) The rapid rise and fall in force produced by a muscle fiber after a single action potential is a(n)

1. A) tetanus.
2. B) unfused tetanus.
3. C) twitch.
4. D) motor end plate potential.
5. E) muscle action potential

C) twitch

70) 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

1. A) incomplete tetanus.
2. B) complete tetanus.
3. C) a twitch.
4. D) wave summation.
5. E) recruitment.

B) complete tetanus

71) A muscle producing almost peak tension during rapid cycles of contraction and relaxation is said to be in

1. A) incomplete tetanus.
2. B) complete tetanus.
3. C) treppe.
4. D) wave summation.
5. E) recruitment.

A) incomplete tetanus

72) 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

1. A) incomplete tetanus.
2. B) complete tetanus.
3. C) treppe.
4. D) wave summation.
5. E) recruitment.

D) wave summation

73) A single motor neuron together with all the muscle fibers it innervates is called a(n)

1. A) end foot.
2. B) end plate.
3. C) motor unit.
4. D) dermatome.
5. E) myotome

C) motor unit

74) The contraction of a muscle exerts a pull on a bone because muscles attach to bones by

1. A) ligaments.
2. B) bursae.
3. C) tendons.
4. D) fasciae.
5. E) myofibrils.

C) tendons

75) The increase in muscle tension that is produced by increasing the number of active motor units is called

1. A) incomplete tetanus.
2. B) complete tetanus.
3. C) treppe.
4. D) wave summation.
5. E) recruitment

E) recruitment

76) The type of contraction in which the muscle fibers do not shorten is called

1. A) tetany.
2. B) treppe.
3. C) concentric.
4. D) isotonic.
5. E) isometric.

E) isometric

77) A weight-lifter strains to lift a heavy weight and there is no movement of the person's arms holding on to the weight. This type of contraction is called a(n) ________ contraction.

1. A) isometric
2. B) tetanus
3. C) isotonic
4. D) treppe
5. E) concentric

A) isometric

78) You try to pick up an object and discover that it is much heavier than you expected. Which process must occur in the muscle to increase tension so you can pick up the object?

1. A) wave summation
2. B) isotonic contraction
3. C) complete tetanus
4. D) recruitment
5. E) treppe

D) recruitment

79) In which of the following would the motor units have the fewest muscle fibers?

1. A) muscles of the neck
2. B) postural muscles of the back
3. C) muscles that control the eyes
4. D) thigh muscles
5. E) calf muscles

C) muscles that control the eyes

80) In an isotonic contraction,

1. A) muscle tension exceeds the load and the muscle lifts the load.
2. B) tension rises and falls but the muscle length is constant.
3. C) the peak tension is less than the load.
4. D) many twitches always fuse into one.
5. E) postural muscles stabilize the vertebrae

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

86) In the liver, during the Cori cycle,

1. A) glucose is released from glycogen.
2. B) lactic acid is produced from glucose.
3. C) glucose is produced from lactic acid.
4. D) lactic acid is produced from pyruvic acid.
5. E) lactic acid is shuffled to muscle cells.

C) glucose is produced from lactic acid

87) During the recovery period the body's need for oxygen is increased because

1. A) muscle cells are producing ATP anaerobically.
2. B) creatine phosphate stimulates mitochondrial activity.
3. C) additional oxygen is required to restore energy reserves.
4. D) the liver requires more oxygen to produce lactic acid.
5. E) the muscles produce much less ATP

C) additional oxygen is required to restore energy reserves

88) A resting muscle generates most of its ATP by

1. A) hydrolysis of creatine phosphate.
2. B) anaerobic respiration.
3. C) aerobic metabolism of fatty acids.
4. D) glycogenolysis.
5. E) the tricarboxylic acid cycle

C) aerobic metabolism of fatty acids

89) Creatine phosphate

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

C) acts as an energy reserve in muscle tissue

90) During anaerobic glycolysis,

1. A) ATP is produced.
2. B) pyruvic acid is produced.
3. C) oxygen is not consumed.
4. D) carbohydrate is metabolized.
5. E) All of the answers are correct

E) All of the answers are correct

91) Aerobic metabolism normally provides ________ percent of the ATP demands of a resting muscle cell.

1. A) 25
2. B) 50
3. C) 70
4. D) 95
5. E) 100

D) 95

92) After heavy exercise, if energy reserves in a muscle are depleted, ________ occurs.

1. A) an oxygen debt
2. B) paralysis
3. C) treppe
4. D) tetanus
5. E) atrophy

A) an oxygen debt

93) During the recovery period following exercise, all of the following are true except

1. A) lactic acid is removed from muscle cells.
2. B) the muscle actively produces ATP.
3. C) muscle fibers are unable to contract.
4. D) oxygen is consumed at above the resting rate.
5. E) heat is generated

C) muscle fibers are unable to contract

94) At peak levels of muscle exertion the mitochondria can supply

1. A) all of the energy required by the muscle.
2. B) 80 percent of the energy required by the muscle.
3. C) more than half of the energy required by the muscle.
4. D) only about one-third of the energy required by the muscle.
5. E) only about 10 percent of the energy required by the muscle

D) only about one-third of the energy required by the muscle

95) Which of the following hormones directly stimulates growth of muscle tissue, leading to increased muscle mass?

1. A) epinephrine
2. B) thyroid hormone
3. C) testosterone
4. D) parathyroid hormone
5. E) calcitonin

C) testosterone

96) Which of the following would not lead to increased oxygen consumption?

1. A) increased heat production
2. B) increased conversion of lactic acid to glucose
3. C) increased anaerobic respiration by muscle cells
4. D) increased muscle activity
5. E) All of the answers are correct; none would lead to increased oxygen consumption

C) increased anaerobic respiration by muscle cells

97) Because skeletal muscle contractions demand large quantities of ATP, skeletal muscles have

1. A) a rich nerve supply to ensure a rapid succession of action potentials.
2. B) massive creatine phosphate reserves for long periods of sustained contractions.
3. C) extra calcium reserves which can serve as fuel molecules during ATP synthesis.
4. D) adipose tissue between fibers to supply nutrients for ATP production.
5. E) many mitochondria and a rich blood supply

E) many mitochondria and a rich blood supply

98) Decreased blood flow to a muscle could result in all of the following except

1. A) muscle fatigue.
2. B) an oxygen debt.
3. C) an increase in intracellular glycogen.
4. D) a shift to anaerobic glycolysis.
5. E) an increase in intracellular lactic acid.

C) an increase in intracellular glycogen

99) How would an elevated level of thyroid hormone in the body affect skeletal muscles?

1. A) It would stimulate atrophy.
2. B) It would stimulate hypertrophy.
3. C) It would stimulate energy use and heat production.
4. D) It would decrease heat production by muscle tissue.
5. E) It would cause an increase in muscle mass

C) It would stimulate energy use and heat production

100) Heat energy gained from muscle contraction is released by the ________ system.

1. A) integumentary
2. B) respiratory
3. C) cardiovascular
4. D) urinary
5. E) endocrine

A) integumentary

101) The type of muscle fiber that is most resistant to fatigue is the ________ fiber.

1. A) fast
2. B) slow
3. C) intermediate
4. D) anaerobic
5. E) high-density

B) slow

102) Fast fibers

1. A) have low resistance to fatigue.
2. B) rely on aerobic metabolism.
3. C) have many mitochondria.
4. D) have twitches with a very brief contraction phase.
5. E) have low resistance to fatigue and quick twitches

E) have low resistance to fatigue and quick twitches

103) Muscles that move the eyeball have ________ fibers.

1. A) fast
2. B) slow
3. C) intermediate
4. D) circular
5. E) All of the answers are correct

A) fast

104) During activities requiring aerobic endurance,

1. A) glycogen and glycolysis are the primary sources of reserve energy.
2. B) oxygen debts are common.
3. C) most of the muscle's energy is produced in mitochondria.
4. D) fatigue occurs in a few minutes.
5. E) oxygen is not required

C) most of the muscle's energy is produced in mitochondria

105) Fast muscle fibers can adapt to aerobic metabolism by generating more mitochondria in response to

1. A) repeated, exhaustive stimulation.
2. B) sustained low levels of muscle activity.
3. C) high amounts of oxygen.
4. D) increased levels of testosterone.
5. E) prolonged periods of inactivity

A) repeated, exhaustive stimulation

106) Which of the following statements is/are false regarding human muscles?

1. A) Most have both slow and fast fibers.
2. B) Slow fibers are abundant in the muscles of the hand.
3. C) Eye muscles are composed entirely of fast fibers.
4. D) Slow fibers are abundant in the back muscles.
5. 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

107) When comparing slow muscle fibers to fast muscle fibers, slow fibers

1. A) take about three times as long to reach peak tension.
2. B) have much smaller fiber diameters.
3. C) generate much less tension.
4. D) are rich in the red protein myoglobin.
5. E) All of the answers are correct

E) All of the answers are correct

108) Large-diameter, densely packed myofibrils, large glycogen reserves, and few mitochondria are characteristics of

1. A) slow fibers.
2. B) intermediate fibers.
3. C) fast fibers.
4. D) red muscles.
5. E) fatty muscles

C) fast fibers

109) Which of the following types of muscle fibers are best adapted for prolonged contraction such as standing all day?

1. A) uninucleated fibers
2. B) striated fibers
3. C) fast fibers
4. D) slow fibers
5. E) intermediate fibers

D) slow fibers

110) Muscular force can be adjusted to match different loads by

1. A) varying the frequency of action potentials in motor neurons.
2. B) recruiting larger motor units.
3. C) recruiting more motor units.
4. D) involving more muscle fibers in the contraction.
5. E) All of the answers are correct

E) All of the answers are correct.

111) Which of the following statements is false?

1. A) Cardiac muscle contractions cannot be summated.
2. B) Skeletal muscle contractions may be summated.
3. C) Skeletal muscle and cardiac muscle stimulation is neural.
4. D) Cardiac muscle has a striated appearance.
5. E) Cardiocytes are interconnected through intercalated discs

C) Skeletal muscle and cardiac muscle stimulation is neural

112) The ability of smooth muscle to function over a wide range of lengths is called

1. A) elasticity.
2. B) contractility.
3. C) extensibility.
4. D) plasticity.
5. E) variability

D) plasticity

113) Which of the following is not characteristic of smooth muscle?

1. A) The striations are due to the orderly arrangement of actin and myosin.
2. B) Neurons that innervate smooth muscles are under involuntary control.
3. C) Smooth muscle cells are uninucleate.
4. D) Smooth muscles do not contain sarcomeres.
5. 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

114) Which of the following is not a function of smooth muscle tissue?

1. A) altering the diameter of the respiratory passageways
2. B) elevating hairs on the arm
3. C) forcing blood from the heart into the major arteries
4. D) moving food materials along the digestive tract
5. E) forcing urine out of the urinary tract

C) forcing blood from the heart into the major arteries

1) A(n) ________ can be described as a broad tendinous sheet.

1. A) fasciae
2. B) retinaculum
3. C) aponeurosis
4. D) interstitium
5. E) tympanum

C) aponeurosis

2) The protein that is found in the Z line of a sarcomere is called

1. A) actinin.
2. B) titin.
3. C) nebulin.
4. D) myosin.
5. E) actin.

A) actinin

3) The protein that regulates muscle contraction by controlling the availability of active sites on actin is called

1. A) actin.
2. B) titin.
3. C) myosin.
4. D) tropomyosin.
5. E) nebulin

D) tropomyosin

4) Thin filaments are mostly made of the protein

1. A) actin.
2. B) titin.
3. C) myosin.
4. D) tropomyosin.
5. E) nebulin

A) actin

5) Thick filaments are made of the protein

1. A) actin.
2. B) titin.
3. C) myosin.
4. D) tropomyosin.
5. E) nebulin.

C) myosin

6) Stem cells located between the endomysium and sarcolemma that function in the repair of damaged muscle tissue are called

1. A) myocytes.
2. B) satellite cells.
3. C) endocytes.
4. D) sarcocytes.
5. E) creatinocytes

B) satellite cells

7) The complex of a transverse tubule and two adjacent terminal cisternae is known as a

1. A) trimer.
2. B) triad.
3. C) triptych.
4. D) trisome.
5. E) trilogy

B) triad

8) The structural theory that explains how a muscle fiber contracts is called the ________ theory.

1. A) sliding filament
2. B) excitation-contraction coupling
3. C) neuromuscular
4. D) muscle contraction
5. E) action-myosin interaction

A) sliding filament

9) Communication between axons and muscle fibers occurs at specialized synapses called

1. A) nervous units.
2. B) synaptic terminals.
3. C) motor end plates.
4. D) motor units.
5. E) neuromuscular junctions.

E) neuromuscular junctions

10) Active sites become exposed when calcium ions bind to

1. A) tropomyosin.
2. B) actin.
3. C) myosin.
4. D) troponin.
5. E) calcium channels

D) troponin

11) Cross bridge detachment is caused by ________ binding to the myosin head.

1. A) ATP
2. B) calcium
3. C) magnesium
4. D) acetylcholine
5. E) acetylcholinesterase

A) ATP

12) The sequence of processes that links the action potential to contraction is called

1. A) neuromuscular junction.
2. B) action potential propagation.
3. C) excitation-contraction coupling.
4. D) cross bridge formation.
5. E) sliding filament theory

C) excitation-contraction coupling

13) An infection by the bacterium Clostridium tetani can cause the disease called

1. A) cholera.
2. B) polio.
3. C) botulism.
4. D) tetanus.
5. E) muscular dystrophy.

D) tetanus

14) A single contraction-relaxation cycle in a muscle fiber produces a(n)

1. A) cramp.
2. B) twitch.
3. C) tetanic contraction.
4. D) action potential.
5. E) motor unit.

B) twitch

15) A muscle produces its highest tension when in complete

1. A) recovery.
2. B) treppe.
3. C) wave summation.
4. D) aerobic metabolism.
5. E) tetanus.

E) tetanus