HCS 215 Chapter 12 Test Bank

1) A skeletal muscle is composed of a bundle of ________, each composed of many muscle fibers wrapped by connective tissue.

A) fascicles

B) myofibrils

C) muscle cells

D) myofilaments

E) sarcomeres

A

2) What structure, composed of connective tissue, transmits force from contracting skeletal muscle to bone?

A) myofibril

B) fascicle

C) tendon

D) ligament

E) aponeurosis

C

3) The fundamental repeating unit of the myofibril, called a ________, gives skeletal muscle its striated appearance and is bordered by ________.

A) crossbridge : Z lines

B) sarcomere : M lines

C) sarcomere : I bands

D) sarcomere : Z lines

E) crossbridge : A bands

D

4) What is the region of the striated muscle's banding patterns that contains only the connections between the tails of myosin molecules and is the mid-point of the sarcomere?

A) A band

B) I band

C) H zone

D) Z line

E) M line

E

5) The contractile portion of the thin filament is composed of what protein?

A) myosin

B) tropomyosin

C) troponin

D) actin

E) titin

D

6) What is the regulatory protein component of the thin filament that binds to calcium, thereby initiating skeletal muscle contraction?

A) myosin

B) tropomyosin

C) troponin

D) actin

E) titin

C

7) Which of the following is a structural protein that extends along each thick filament from M line to Z line?

A) titin

B) actin

C) myosin

D) tropomyosin

E) troponin

A

8) The shortening of a skeletal muscle fiber during contraction involves which of the following?

A) the thick filaments shortening

B) the thin filaments shortening

C) the sarcomeres shortening

D) the A bands shortening

E) the Z lines not changing their position

C

9) During skeletal muscle contraction, as the muscle shortens, the thick and thin filaments

A) shorten.

B) slide past one another.

C) do not interact.

D) condense.

E) lengthen.

B

10) When a skeletal muscle is passively stretched, that cell has a tendency to spring back once the force that was stretching the muscle is removed due to

A) the passive interaction between actin and myosin (no energy required).

B) the active interaction between actin and myosin (energy required).

C) titin acting as a spring using the energy stored by the stretching.

D) actin and myosin acting as a spring using the energy stored by the stretching.

E) the elastic connective tissue that surrounds the muscle cells and fascicles.

C

11) The repeated, oscillating interaction between actin and myosin which results in the generation of force by a skeletal muscle cell is called what?

A) crossbridge cycling

B) the sliding-filament model

C) Z line interaction

D) sarcomeric facilitation

E) titin cycling

A

12) What converts the myosin head into the high-energy state?

A) binding to ATP only

B) binding to actin

C) the condensation of ATP

D) the hydrolysis of ATP

E) binding to titin

D

13) The release of an inorganic phosphate from the myosin molecule directly results in which of the following?

A) development of rigor

B) power stroke

C) cocking of the myosin head

D) binding of actin to myosin

E) breaking of the actin myosin complex

B

14) In order for crossbridge cycling to occur, the actin-myosin complex must be broken by which of the following?

A) binding of tropomyosin to myosin

B) binding of ATP to actin

C) binding of the troponin complex to actin

D) conformational change that occurs as the myosin head changes from the high to low energy state

E) binding of ATP to myosin

E

15) The sequence of events that links the muscle's action potential to changes in skeletal muscle force development is called what?

A) the sliding-filament model

B) crossbridge cycling

C) myoaction coupling

D) excitation-contraction coupling

E) oxidative phosphorylation

D

16) During skeletal muscle contraction, multiple crossbridge cycles are occurring between the same thick and thin filament. Which of the following best describes this process?

A) Crossbridge cycling is highly synchronized between a certain thick and thin filament.

B) Crossbridge cycling is asynchronous between a certain thick and thin filament.

C) No more than one myosin head links to the thin filament at the same time.

D) No more than one myosin head detaches from the thin filament at the same time.

E) Tropomyosin only exposes one binding site on actin at a time allowing only one crossbridge to form with actin at a given time.

B

17) Contraction of skeletal muscle fibers is stimulated by what type of neuron?

A) autonomic

B) sympathetic

C) motor

D) parasympathetic

E) afferent

C

18) Which of the following is NOT a specialization observed at the neuromuscular junction?

A) There is a high density of acetylcholine receptors in the motor end plate.

B) Every action potential that reaches the axon terminal of the motor neuron will generate an action potential in the healthy muscle fiber.

C) The motor end plate is relatively large compared with other synapses.

D) The terminal bouton fans out over a wide area of the sarcolemma.

E) Each muscle fiber is innervated by multiple motor neurons.

E

19) Increases in the amount of cytoplasmic calcium required to initiate a muscle contraction are mediated by the coupling between a ________ on the T tubule and a ________ on the membrane of the sarcoplasmic reticulum.

A) dihydropyridine receptor : calcium pump

B) dihydropyridine receptor : ryanodine receptor

C) ryanodine receptor : calcium pump

D) calcium pump : ryanodine receptor

E) calcium-induced calcium release channel : dihydropyridine receptor

B

20) Which of the following is the voltage sensor that initiates an increase in cytoplasmic calcium in response to an action potential?

A) dihydropyridine receptor

B) ryanodine receptor

C) calcium pump

D) calcium-induced calcium release channel

E) sodium channel

A

21) The binding of calcium to troponin will directly allow which of the following?

A) the binding of ATP to myosin

B) the further release of calcium into the cytoplasm

C) the movement of tropomyosin, thereby exposing the myosin-binding site on the actin molecule

D) the movement of tropomyosin, thereby exposing the actin-binding site on the myosin molecule

E) the hydrolysis of ATP

C

22) What area of a sarcomere shows up as light striations when viewed under a microscope?

A) A band

B) I band

C) H zone

D) M line

E) Z line

B

23) Which of the following best describes the interaction between transverse (T) tubules and the sarcoplasmic reticulum in skeletal muscle contraction?

A) Action potentials in T tubules trigger the release of acetylcholine, which binds to receptors on the sarcoplasmic reticulum and triggers calcium release.

B) Action potentials in T tubules trigger the release of norepinephrine, which binds to receptors on the sarcoplasmic reticulum and triggers calcium release.

C) Action potentials in T tubules are detected by DHP receptors, which are coupled to ryanodine receptors in the sarcoplasmic reticulum and open channels for calcium.

D) Action potentials in T tubules are detected by ryanodine receptors, which are coupled to DHP receptors in the sarcoplasmic reticulum and open channels for calcium.

E) Action potentials in T tubules cause a depolarization of the sarcoplasmic reticulum membrane, thereby opening calcium channel

C

24) During the cross-bridge cycle, ATP binding to myosin causes which of the following?

A) the myosin head to attach to actin

B) the myosin head to detach from actin

C) the myosin head to swing forward pulling actin toward the M line

D) the myosin head to interact with calcium channels, triggering calcium release from the sarcoplasmic reticulum

E) the myosin head to be in its high-energy form

B

25) What is the function of T tubules?

A) They store calcium.

B) Actin and myosin are synthesized here.

C) They conduct action potentials from the sarcolemma to the interior of the muscle cell.

D) They provide elasticity to the muscle.

E) They hold the thick filaments to the Z line.

C

26) What is a motor unit?

A) all the muscle fibers in a fascicle

B) all the myofibrils in a muscle fiber

C) a muscle fiber and all the motor neurons that innervate it

D) a motor neuron and all the muscle fibers it innervates

E) a spinal nerve and all the muscle fibers it innervates

D

27) In order to allow discrete contractile events to occur, calcium is rapidly removed from the cytoplasm via

A) calcium pumps (active transport of calcium).

B) dihydropyridine receptors.

C) ryanodine channels.

D) calcium-sequestering proteins in the cytoplasm.

E) calcium-binding proteins on the sarcoplasmic reticulum.

A

28) Which of the following is not part of the process whereby skeletal muscles relax?

A) Sarcolemmal calcium channels open to allow the efflux of calcium.

B) The binding of calcium to a low-affinity site closes sarcoplasmic reticulum calcium channels.

C) A calcium pump actively removes calcium.

D) The amount of calcium bound to troponin decreases.

E) A myosin-binding site on the actin molecule is blocked by tropomyosin.

A

29) What enzyme catalyzes the reaction that creates creatine phosphate?

A) creatine phosphatase

B) creatine hydrolase

C) creatine hydrogenase

D) creatine kinase

E) ATP hydrolase

D

30) Since the creatine phosphorylation reaction is substrate driven, an increase in the concentration of creatine within a skeletal muscle fiber will directly have what effect?

A) increase creatine phosphate concentration

B) decrease creatine phosphate concentration

C) increase ATP generation

D) decrease creatine kinase activity

E) increase glucose metabolism

A

31) During intense (heavy) exercise, the initial ability of oxidative phosphorylation to provide enough ATP for the sudden demand of increased force generation by the skeletal muscle is ________, thereby causing the muscle fiber to quickly and massively boost its energy production from ________ until oxygen delivery and other mechanisms come up to speed.

A) enhanced : substrate-level phosphorylation

B) inadequate : substrate-level phosphorylation

C) enhanced : fatty acids

D) enhanced : glucose

E) inadequate : fatty acids

B

32) As the intensity of exercise increases (and the potential gap between energy demand and creation threatens to widen), the muscles quickly underwrite their escalating energy demands by augmenting oxidative with substrate-level phosphorylation, resulting in the increased generation of which of the following?

A) lactic acid

B) water from the electron transport chain

C) glucose

D) fatty acid

E) ATP

A

33) When an action potential is generated within a motor neuron,

A) the muscle cells of the motor unit will occasionally contract.

B) only select muscle cells within the motor unit are stimulated to contract.

C) every muscle cell of the motor unit is stimulated to contract.

D) the muscle cells from a neighboring motor unit will contract.

E) all of the muscle cells within the motor unit are stimulated to relax.

C

34) Which is the longest phase of a twitch?

A) latent

B) contraction

C) plateau

D) relaxation

E) initial

D

35) Which of the following is NOT part of the explanation for the all-or-nothing property of an isometric twitch contraction of skeletal muscle?

A) equivalent calcium reuptake by the sarcoplasmic reticulum

B) equivalent calcium released by each action potential

C) equivalent activation of calmodulin stimulating myosin light-chain kinase activity

D) equal numbers of crossbridges activated by the calcium released

E) all-or-nothing property of the action potential generated by a skeletal muscle

C

36) Which of the following is a property of isometric skeletal muscle contraction?

A) rapid shortening of the muscle

B) rapid lengthening of the muscle

C) Load is greater than the force generated by the muscle.

D) Load is equal to the force generated by the muscle.

E) Load is less than the force generated by the muscle.

C

37) Which of the following is a property of isotonic skeletal muscle contraction?

A) There is a slow increase in force with no change in muscle length.

B) There is a rapid increase in force with no change in muscle length.

C) Muscle length will be increased by contraction.

D) Load is greater than the force generated by the muscle.

E) Load is less than the force generated by the muscle.

E

38) Which of the following statements about excitation-contraction coupling in skeletal muscle is FALSE?

A) An action potential in the sarcolemma stimulates the opening of voltage-gated calcium channels in the plasma membrane and the sarcoplasmic reticulum.

B) Calcium binds to troponin, causing a shift in tropomyosin, thereby exposing the binding sites on actin for myosin.

C) DHP receptors on the T tubules detect changes in voltage and communicate to ryanodine receptors on the sarcoplasmic reticulum to open calcium channels.

D) An end-plate potential triggers an action potential on the sarcolemma.

E) Calcium ATPases in the sarcoplasmic reticulum are necessary for relaxation of the muscle.

A

39) Which of the following statements about end-plate potentials is FALSE?

A) They are graded potentials.

B) They are always depolarizations.

C) They are almost always of sufficient magnitude to generate an action potential in the sarcolemma.

D) They are a result of acetylcholine binding to muscarinic cholinergic receptors.

E) They are terminated by removal of acetylcholine from the synaptic cleft.

D

40) Which of the following best describes an isotonic contraction?

A) When the contractile elements shorten, they lengthen the elastic elements but do not move the load.

B) When the contractile elements shorten, they create enough force to move the load.

C) When the contractile elements lengthen, they shorten the elastic elements and move the load.

D) When the contractile elements lengthen, they lengthen the elastic elements but do not move the load.

E) The contractile elements stay the same length as the elastic elements shorten and move the load.

B

41) The speed with which the skeletal muscle generates force is determined primarily by

A) the amount of energy available.

B) the type of myosin and its ATPase present.

C) actin.

D) troponin.

E) tropomyosin.

B

42) Which of the following is the property of skeletal muscle whereby an increase in the frequency of action potentials enhances the force developed by the muscle cell?

A) length-tension relationship

B) summation

C) force-velocity relationship

D) external tension

E) internal tension

B

43) The tension produced during skeletal muscle contraction can be increased by all of the following EXCEPT

A) recruiting motor units.

B) increasing the frequency of action potentials in the motor neuron innervating the muscle.

C) increasing the frequency of action potentials in the muscle fiber.

D) initiating the contraction when the muscle is at its optimum length.

E) increasing the load on the muscle.

E

44) Which of the following statements about summation and tetanus is FALSE?

A) Summation and tetanus occur at high frequencies of skeletal muscle stimulation.

B) Summation and tetanus do not occur in cardiac muscle.

C) Summation and tetanus result from increases in cytosolic calcium levels.

D) Summation and tetanus result in greater tension in the muscle.

E) The maximum tension developed during summation and tetanus is treppe.

E

45) Once a skeletal muscle cell begins to shorten during an isotonic twitch contraction,

A) the amount of force generated by the muscle will continue to increase.

B) the amount of force generated by the muscle will start to decrease.

C) the amount of force generated by the muscle will remain constant.

D) the muscle will continue to shorten until the force generated by the muscle stops increasing.

E) the muscle will stop shortening once the force is greater than the load.

C

46) Which of the following conditions will result in a skeletal muscle that produces a greater amount of force?

A) more sarcomeres in series

B) more sarcomeres in parallel

C) fewer myofibrils per muscle cell

D) fewer sarcomeres in parallel

E) fewer sarcomeres in series

B

47) Which of the following is NOT an accurate description of specific muscle fiber types?

A) Fast glycolytic fibers are the largest diameter fibers.

B) Slow oxidative fibers are the smallest diameter fibers.

C) Slow oxidative fibers are quick to fatigue.

D) Fast glycolytic fibers produce their ATP by glycolysis.

E) Fast oxidative fibers have a high mitochondrial density.

C

48) As skeletal muscle is further stretched beyond the length where optimum force is developed,

A) the amount of calcium released by the sarcoplasmic reticulum is reduced as length increases.

B) the thin filaments are pulled away from the thick filaments, thereby reducing actin's ability to interact with myosin.

C) the thick filaments are pulled away from one another, thereby reducing their ability to interact with actin.

D) the thick filaments overlap one another, thereby reducing their ability to interact with actin.

E) the thin filaments overlap one another, thereby reducing their ability to interact with myosin.

B

49) As the sarcomere length of skeletal muscle is reduced beyond the length where optimum force is developed,

A) the amount of calcium released by the sarcoplasmic reticulum is reduced as length increases.

B) the thin filaments are pulled away from one another, thereby reducing their ability to interact with myosin.

C) the thick filaments are pulled away from one another, thereby reducing their ability to interact with actin.

D) the thick filaments overlap one another, thereby reducing their ability to interact with actin.

E) the thin filaments overlap one another with myosin bumping into the Z-line, thereby causing the force generated by crossbridges to be exerted on the sarcomere itself rather than transmitted to the ends of the muscle fiber.

E

50) In the body, the sarcomere length of skeletal muscle cells is usually

A) much less than optimum length.

B) near optimal.

C) much greater than optimum length.

D) quite variable from one muscle to the next.

E) 3 microns.

B

51) Which of the following does NOT influence the force generated by an individual muscle fiber?

A) frequency of stimulation

B) fiber diameter

C) length at onset of contraction

D) recruitment

E) summation

D

52) What is an increase in the number of active motor units that would increase the force developed by a skeletal muscle called?

A) recruitment

B) summation

C) treppe

D) tetanus

E) length-tension relationship

A

53) Contraction of motor units in a(n) ________ manner allows a muscle to maintain a smooth level of force for a duration of time without fatiguing.

A) synchronous

B) asynchronous

C) asymmetrical

D) symmetrical

E) random

B

54) Which of the following BEST describes the relationship between motor neuron size, motor unit size, and order of recruitment?

A) large motor neurons : small motor unit : first to be recruited

B) large motor neurons : small motor unit : last to be recruited

C) large motor neurons : large motor unit : first to be recruited

D) large motor neurons : large motor unit : last to be recruited

E) There is no relationship.

D

55) A muscle is stimulated at a frequency that allows the muscle to relax completely between contractions. However, the amount of tension increases with each contraction. What is this called?

A) twitch

B) summation

C) tetanus

D) recruitment

E) treppe

E

56) The mechanism responsible for the size principle involves

A) larger motor neurons that innervate the greatest number of muscle cells and reach threshold easier than smaller neurons.

B) larger sympathetic neurons that contain the greatest number of muscle cells and reach threshold easier than smaller neurons.

C) smaller sympathetic neurons that contain the least number of muscle cells and reach threshold easier than larger neurons.

D) smaller motor neurons that innervate the least number of muscle cells and reach threshold easier than larger neurons.

E) smaller motor units that contain the greatest number of muscle cells and reach threshold easier than larger neurons.

D

57) Which of the following is NOT a property of glycolytic fibers as compared to oxidative fibers?

A) high capacity for lactic acid production

B) fewer capillaries

C) absence of myoglobin

D) poor ability to produce ATP in the absence of oxygen

E) readily fatigable

D

58) What molecule, present primarily within oxidative skeletal muscle cells, acts as an oxygen buffer due to its ability to bind oxygen?

A) hemoglobin

B) myoglobin

C) lactic acid

D) myosin

E) myosin light chain

B

59) What causes some muscle fibers to appear red and dark?

A) greater blood supply

B) presence of myoglobin

C) presence of lots of mitochondria

D) high concentration of actin and myosin

E) presence of myoglobin and lots of mitochondria

B

60) What is the site where a muscle attaches to a stationary bone called?

A) origin

B) insertion

C) abductor

D) adductor

E) flexor

A

61) What connects muscles to bone?

A) ligaments

B) tendons

C) cartilage

D) capillaries

E) T tubules

B

62) Relative to the triceps muscle, the biceps is its

A) origin.

B) insertion.

C) agonist.

D) antagonist.

E) abductor.

D

63) What type of receptor detects muscle length?

A) DHP

B) ryanodine

C) muscle spindle

D) Golgi tendon organ

E) nociceptor

C

64) What is an annulospiral ending?

A) a structure in the cochlea that contains hair cells

B) sensory endings in the muscle spindle that detect muscle length

C) sensory endings in the Golgi tendon organ that detect muscle tension

D) a structure in the semicircular canals that contains hair cells

E) a structure in the utricle that contains hair cells

B

65) What type of efferent neuron innervates intrafusal muscle fibers?

A) type Ia

B) type Ib

C) type II

D) alpha motor neurons

E) gamma motor neurons

E

66) Which of the following statements is TRUE regarding activation of alpha and gamma motor neurons?

A) Alpha and gamma motor neurons are activated at the same time.

B) Alpha motor neurons are activated before gamma motor neurons.

C) Gamma motor neurons are activated before alpha motor neurons.

D) During light activity, alpha motor neurons are activated first; during heavy activity, gamma motor neurons are activated first.

E) During light activity, gamma motor neurons are activated first; during heavy activity, alpha motor neurons are activated first.

A

67) Which of the following is the correct order of muscle fiber recruitment, from first to last?

A) slow oxidative : fast oxidative : fast glycolytic

B) fast oxidative : fast glycolytic : slow oxidative

C) fast glycolytic : fast oxidative : slow oxidative

D) slow oxidative : fast glycolytic : fast oxidative

E) fast glycolytic : slow oxidative : fast oxidative

A

68) Which of the following muscle types has the slowest contraction time?

A) fast glycolytic skeletal muscle

B) fast oxidative skeletal muscle

C) slow oxidative skeletal muscle

D) smooth muscle

E) cardiac muscle

D

69) Which of the following mechanisms does NOT account for the decrease in force development by muscle cells during sustained force development?

A) Compression of muscle during contraction can reduce blood flow to the muscle.

B) Repeated action potentials along the same neuron can lead to neuromuscular fatigue.

C) The crossbridges can become resistant to ATP.

D) Oxidative fibers can be depleted of glycogen, their primary energy source.

E) Glycolytic fibers produce lactic acid and inhibit enzyme activity with their hydrogen ion.

C

70) Which of the following is NOT an adaptation of skeletal muscle that would be observed in response to aerobic training?

A) an increase in mitochondrial density

B) an increase in capillary density

C) an increase in the number of oxidative fibers

D) an increase in the diameter of the skeletal muscle fibers

E) an increase in the concentration of oxidative enzymes

D

71) Where are gap junctions commonly found?

A) single-unit smooth muscle only

B) multi-unit smooth muscle only

C) cardiac muscle only

D) both single-unit smooth muscle and cardiac muscle

E) both single-unit and multi-unit smooth muscle

D

72) Which of the following is true of ALL muscle types?

A) They contract by using the sliding filament mechanism and crossbridge cycling.

B) They are striated.

C) They contain T tubules.

D) They contain calmodulin.

E) Recruitment increases the strength of contraction.

A

73) In smooth muscle, calcium triggers contraction by binding to what protein?

A) troponin

B) myosin light chain kinase

C) myosin light chain

D) calmodulin

E) DHP receptors

D

74) Calcium binding to calmodulin causes phosphorylation by myosin light chain kinase of what protein in what type of muscle?

A) troponin in skeletal and cardiac muscle only

B) troponin in smooth muscle only

C) actin in cardiac and smooth muscle

D) actin in smooth muscle only

E) myosin in smooth muscle only

E

75) Which of the following adaptations does NOT generally occur with aerobic exercise?

A) an increase in the number of mitochondria per muscle fiber

B) an increase in the number of myofibrils per muscle fiber

C) a conversion of fast glycolytic fibers to fast oxidative fibers

D) an increase in the blood supply to the muscles

E) an increase in the aerobic capacity of muscle

B

76) The interaction between actin and myosin in smooth muscle requires

A) the interaction between calcium and troponin to expose the myosin binding site on the actin molecule.

B) that the calcium-calmodulin complex activates myosin light-chain kinase, which phosphorylates myosin thereby allowing it to bind with actin.

C) the tropomyosin must be moved out of the way by troponin before myosin can bind to actin.

D) the activation of troponin, which stimulates myosin light-chain kinase to phosphorylate myosin light chain, allowing myosin to bind with actin.

E) that the calcium-calmodulin complex directly phosphorylates myosin light chain, allowing myosin to bind to actin.

B

77) What is the source of variability in the response of smooth muscle cells from different organs to autonomic nervous activity (some relax to sympathetic nervous output while others contract)?

A) the amount of neurotransmitter released into the synaptic cleft

B) the duration of neurotransmitter release from the autonomic neurons

C) the neurotransmitter released by the autonomic nervous system

D) the type of receptor present on the effector organ

E) the presynaptic modulation of the autonomic neurons

D

78) Which of the following could cause a pacemaker potential?

A) spontaneous opening of potassium channels

B) spontaneous closing of calcium channels

C) spontaneous opening of sodium channels

D) spontaneous opening of chloride channels

E) All of the answers are correct.

C

79) Which of the following stores calcium to be released for muscle contraction?

A) sarcomeres

B) tendons

C) sarcoplasmic reticulum

D) actin and myosin

E) motor end plate

C

80) Which of the following transmits action potentials to the interior of the muscle cell to trigger calcium release?

A) actin and myosin

B) sarcomeres

C) tendons

D) sarcoplasmic reticulum

E) motor end plate

E

81) Which of the following generates the mechanical force of a muscle through crossbridge cycling?

A) actin and myosin

B) motor end plate

C) sarcomeres

D) tendons

E) sarcoplasmic reticulum

A

82) Which of the following attaches muscle to bone?

A) sarcomeres

B) sarcoplasmic reticulum

C) tendons

D) actin and myosin

E) motor end plate

C

83) What is the functional unit of skeletal muscle?

A) motor end plate

B) sarcomeres

C) actin and myosin

D) tendons

E) sarcoplasmic reticulum

B

84) Which of the following contains ryanodine receptors?

A) tendons

B) sarcoplasmic reticulum

C) motor end plate

D) sarcomeres

E) actin and myosin

B

85) Which of the following contains DHP receptors?

A) motor end plate

B) sarcoplasmic reticulum

C) transverse tubules

D) tendons

E) sarcomeres

C

86) Which of the following contains nicotinic cholinergic receptors?

A) actin and myosin

B) sarcoplasmic reticulum

C) sarcomeres

D) tendons

E) motor end plate

E

87) Which of the following extends the length of the thick filaments?

A) H zone

B) A band

C) M line

D) I band

E) Z line

B

88) What region of thick filaments has no overlap with thin filaments?

A) H zone

B) Z line

C) M line

D) I band

E) A band

A

89) What is the region of thin filaments that has no overlap with thick filaments called?

A) Z line

B) M line

C) H zone

D) A band

E) I band

E

90) What anchors thin filaments together?

A) M line

B) A band

C) H zone

D) I band

E) Z line

E

91) What anchors thick filaments together?

A) H zone

B) M line

C) I band

D) A band

E) Z line

B

92) Which of the following appears as light bands under the microscope?

A) M line

B) I band

C) H zone

D) Z line

E) A band

B

93) Which of the following appears as dark bands under the microscope?

A) M line

B) A band

C) I band

D) Z line

E) H zone

B

94) Which protein binds calcium in smooth muscle cells?

A) troponin

B) myosin light-chain kinase

C) calmodulin

D) tropomyosin

E) titin

C

95) What binds calcium in skeletal muscle cells?

A) tropomyosin

B) myosin light-chain kinase

C) troponin

D) calmodulin

E) titin

C

96) What binds calcium in cardiac muscle cells?

A) troponin

B) tropomyosin

C) calmodulin

D) titin

E) myosin light-chain kinase

C

97) What are the elastic fibers that anchor thick filaments in place?

A) troponin

B) myosin light-chain kinase

C) calmodulin

D) titin

E) tropomyosin

D

98) What is the enzyme that modulates the ability of myosin to bind actin in smooth muscle?

A) troponin

B) tropomyosin

C) myosin light-chain kinase

D) calmodulin

E) titin

C

99) Which type of skeletal muscle fiber contains a high concentration of mitochondria?

A) slow

B) fermentative

C) oxidative

D) glycolytic

E) fast

C

100) Which type of skeletal muscle fiber contains high shortening velocities?

A) slow

B) fast

C) fermentative

D) oxidative

E) glycolytic

B