Deck 9: Skeletal Muscle Tissue

Question 1

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) all of the above

Answer 1

B

Question 2

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) any of the above

Answer 2

B

Question 3

Skeletal muscle fibers are formed from embryonic cells called

A) sarcomeres.
B) myofibrils.
C) myoblasts.
D) fascicles.
E) myomeres.

Answer 3

C

Question 4

Which of the following statements is incorrect?

A) The contractions of skeletal muscles pull on tendons and move bones of the skeleton.
B) Skeletal muscles store nutrient reserves.
C) Skeletal muscles are responsible for the pumping action of the heart.
D) Skeletal muscles support the weight of some internal organs.
E) Skeletal muscle contractions help maintain body temperature.

Question 5

Each skeletal muscle fiber contains ________ myofibrils.

A) 50 to 100
B) 100 to 150
C) 150 to 200
D) 200 to 500
E) hundreds to thousands

Question 6

At each end of the muscle, the collagen fibers of the epimysium, and each perimysium and endomysium, come together to form a

A) tendon.
B) satellite cell.
C) ligament.
D) tenosynovium.
E) sheath.

Question 7

The advantage of having many nuclei in a skeletal muscle fiber is

A) the ability to contract.
B) the ability to produce more ATP with little oxygen.
C) the ability to store extra DNA for metabolism.
D) the ability to produce large amounts of the muscle proteins needed for muscle contraction.
E) all of the above

Question 8

The repeating unit of a skeletal muscle fiber is the

A) sarcolemma.
B) sarcomere.
C) sarcoplasmic reticulum.
D) myofibril.
E) myofilament.

Question 9

The plasma membrane of skeletal muscle is called the

A) sarcolemma.
B) sarcomere.
C) sarcosome.
D) sarcoplasmic reticulum.
E) sarcoplasm.

Question 10

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.

Question 11

Individual muscle cells are surrounded by

A) endomysium.
B) perimysium.
C) sarcolemma.
D) sarcomere.
E) myofibrils.

Question 12

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 above

Question 13

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

Question 14

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.

Question 15

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.

Question 16

Which of the following best describes the 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

Question 17

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.

Question 18

The dense layer of connective tissue that surrounds an entire skeletal muscle is the

A) tendon.
B) epimysium.
C) endomysium.
D) perimysium.
E) fascicle.

Question 19

The types of muscle tissue include all of the following, except

A) striated muscle.
B) cardiac muscle.
C) smooth muscle.
D) skeletal muscle.
E) none of the above

Question 20

Nerves and blood vessels that service the muscle fibers are located in the connective tissues of the

A) endomysium.
B) perimysium.
C) sarcolemma.
D) sarcomere.
E) myofibrils.

Question 21

Figure 9-1 Skeletal Muscle Fiber
Use Figure 9-1 to answer the following questions:
What is released from the structure labeled "9"?

A) sarcoplasm
B) acetylcholine
C) protein
D) calcium ions
E) acetylcholinesterase

Question 22

Each thin filament consists of

A) two protein strands coiled helically around each other.
B) chains of myosin molecules.
C) six molecules in a rod like structure.
D) a rod-shaped structure with "heads" projecting from each end.
E) a double strand of myosin molecules.

Question 23

Compared to a "typical" body cell, skeletal muscle cells are

A) larger than normal cells.
B) multinucleate.
C) filled with cylindrical structures containing contractile proteins.
D) capable of rapid shortening against a load.
E) all of the above

Question 24

Figure 9-1 Skeletal Muscle Fiber
Use Figure 9-1 to answer the following questions:
Which structure contains the motor end plate?

A) 1
B) 2
C) 3
D) 5
E) 8

Question 25

The skeletal muscle complex known as the triad consists of

A) actin, myosin, and 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.

Question 26

Figure 9-1 Skeletal Muscle Fiber
Use Figure 9-1 to answer the following questions:
What physiological process occurs in the structure labeled "7"?

A) release of neurotransmitter
B) conduction of the action potential into the cell interior
C) activity of acetylcholinesterase
D) release of protein into the muscle fiber
E) the sliding filament theory

Question 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.

Question 28

Figure 9-1 Skeletal Muscle Fiber
Use Figure 9-1 to answer the following questions:
Identify the structure where ATP is produced.

A) 6
B) 7
C) 1
D) 3
E) 2

Question 29

Which of the following best describes the term titin?

A) protein that accounts for elasticity of resting muscle
B) repeating unit of striated myofibrils
C) storage site for calcium ions
D) where thin filaments are anchored
E) largely made of myosin molecules

Question 30

Figure 9-1 Skeletal Muscle Fiber
Use Figure 9-1 to answer the following questions:
Where is ATP is consumed?

A) 1
B) 2
C) 3
D) 6
E) 3 and 6

Question 31

In a sarcomere, thick filaments are linked laterally by proteins of the

A) Z line.
B) M line.
C) H band.
D) A band.
E) I band.

Question 32

Figure 9-1 Skeletal Muscle Fiber
Use Figure 9-1 to answer the following questions:
Which of the following are found in the structure labeled "3"?

A) actin
B) myosin
C) titin
D) tropomyosin
E) all of the above

Question 33

Which statement about the microscopic anatomy of skeletal muscle fibers is True ?

A) Tubular extensions of the sarcolemma penetrate the fiber transversely.
B) Cross striations result from the lateral alignment of thick and thin filaments.
C) Each fiber has many nuclei.
D) Muscle fibers are continuous from tendon to tendon.
E) All are True .

Question 34

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.

Question 35

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) where thin filaments are anchored
E) largely made of myosin molecules

Question 36

Figure 9-1 Skeletal Muscle Fiber
Use Figure 9-1 to answer the following questions:
Where would calcium ion be predominately found?

A) 1
B) 2
C) 4
D) 8
E) 9

Question 37

Figure 9-1 Skeletal Muscle Fiber
Use Figure 9-1 to answer the following questions:
Which structure actively pumps calcium ions out of the sarcoplasm to produce relaxation?

A) 6
B) 7
C) 1
D) 3
E) 2

Question 38

Figure 9-1 Skeletal Muscle Fiber
Use Figure 9-1 to answer the following questions:
Where are the myosin molecules located?

A) 4
B) 5
C) 6
D) 7
E) 8

Question 39

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.

Question 40

Figure 9-1 Skeletal Muscle Fiber
Use Figure 9-1 to answer the following questions:
Identify the structures labeled " 1."

A) mitochondria
B) glycogen
C) ATP
D) myofibril
E) synaptic vesicle

Question 41

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.

Question 42

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

A) epinephrine.
B) norepinephrine.
C) acetylcholine.
D) antidiuretic hormone.
E) all of the above

Question 43

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.

Question 44

Triggering of the muscle action potential occurs after

A) acetylcholine binds to chemically gated channels in the motor end plate membrane.
B) acetylcholinesterase binds to receptors on the end plate.
C) calcium ion binds to channels on the end plate.
D) the nerve action potential jumps across the neuromuscular junction.
E) Any of the above can produce an action potential in the muscle cell.

Question 45

Receptors for acetylcholine are located on the

A) synaptic knob.
B) motor end plate.
C) sarcomere.
D) synaptic cleft.
E) transverse tubule.

Question 46

Cross-bridges are portions of

A) actin molecules.
B) myosin molecules.
C) troponin molecules.
D) tropomyosin molecules.
E) calcium ions.

Question 47

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 and H band distance is constant during contraction.

Question 48

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.

Question 49

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.

Question 50

When acetylcholine binds to receptors at the motor end plate, the end plate membrane becomes

A) more permeable to sodium ions.
B) less permeable to sodium ions.
C) more permeable to calcium ions.
D) less permeable to potassium ions.
E) repolarized.

Question 51

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.

Question 52

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

Question 53

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

A) It would make the muscles less excitable.
B) It would produce muscle weakness.
C) It would cause spastic paralysis (muscles are contracted and unable to relax).
D) It would cause flaccid paralysis (muscles are relaxed and unable to contract).
E) It would have little effect on skeletal muscles.

Question 54

The thin filaments of striated muscle are made of which protein(s)?

A) actin
B) tropomyosin
C) troponin
D) nebulin
E) all of the above

Question 55

Synaptic vesicles containing neurotransmitters are released by ________ when the action potential arrives.

A) endocytosis
B) apoptosis
C) exocytosis
D) hydrolysis
E) sodium

Question 56

When calcium ion binds to troponin,

A) tropomyosin moves into the groove between the helical actin strands.
B) active sites on the myosin are exposed.
C) actin heads will bind to myosin.
D) muscle relaxation occurs.
E) myosin shortens.

Question 57

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) not enough information to say

Question 58

When a skeletal muscle fiber contracts,

A) the H bands and I bands get smaller.
B) the zones of overlap get larger.
C) the Z lines get closer together.
D) the width of the A band remains constant.
E) all of the above

Question 59

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.

Question 60

How would a drug that blocks acetylcholine receptors at the motor end plate affect skeletal muscle?

A) It would make the muscles more excitable.
B) It would produce uncontrolled muscle spasms.
C) It would cause spastic paralysis (muscles are contracted and unable to relax).
D) It would cause flaccid paralysis (muscles are relaxed and unable to contract).
E) It would have little effect on skeletal muscles.

Question 61

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.

Question 62

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

A) a tetanus.
B) an unfused tetanus.
C) a twitch.
D) an end plate potential.
E) a muscle action potential.

Question 63

Which of the following muscles would contract more forcefully?

A) a muscle receiving 10 to 15 action potentials per second
B) a muscle receiving 20 to 25 action potentials per second

Question 64

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

A) actin molecules
B) troponin molecules
C) tropomyosin molecules
D) the head portion of the myosin molecule
E) the tail portion of the myosin molecule

Question 65

Which of the following is greater?

A) the concentration of calcium ion in the sarcoplasm of a resting muscle
B) the concentration of calcium ion in the sarcoplasmic reticulum of a resting muscle

Question 66

Figure 9-2 Muscle Contractions
Use Figure 9-2 to answer the following questions:
What is the contraction in graph (d) called?

A) complete tetanus
B) incomplete tetanus
C) twitch
D) wave summation
E) treppe

Question 67

Calcium ions are binding to troponin during the ________ of a muscle twitch.

A) latent period
B) contraction phase
C) recovery phase
D) relaxation phase
E) latent period and the contraction phase

Question 68

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

Question 69

Muscular force can be adjusted to match different loads by

A) varying the frequency of action potentials in motor neurons.
B) recruiting larger motor units.
C) recruiting more motor units.
D) all of the above
E) None of the above.muscle contraction is all-or-none.

Question 70

If a second stimulus arrives before the relaxation phase has ended, a second, more powerful contraction occurs. This is called

A) incomplete tetanus.
B) complete tetanus.
C) treppe.
D) wave summation.
E) recruitment.

Question 71

Which statement about excitation-contraction coupling is incorrect?

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

Question 72

A single motor neuron together with all the muscle fibers it innervates is called

A) an end foot.
B) an end plate.
C) a motor unit.
D) a dermatome.
E) a myotome.

Question 73

Figure 9-2 Muscle Contractions
Use Figure 9-2 to answer the following questions:
To produce a contraction similar to the one in graph (b), the muscle

A) must be stimulated to the point of fatigue.
B) must be stimulated again before it has relaxed from the previous stimulation.
C) is excited by a stimulus of increasing intensity.
D) is caused to produce isolated twitches.
E) gradually warms up.

Question 74

What is thought to happen in a muscle during the response shown in graph (a)?

A) It is getting stronger with exercise.
B) There is a gradual increase in the concentration of calcium ions in the sarcoplasm.
C) It is fatigued and must make repeated efforts to twitch normally.
D) It is aged and has lost contractile proteins.
E) It is producing more ATP as tension increases.

Question 75

A muscle producing tension that peaks and falls at intermediate stimulus rates is said to be in

A) incomplete tetanus.
B) complete tetanus.
C) treppe.
D) wave summation.
E) recruitment.

Question 76

Which of the following motor units would produce the greatest tension?

A) a motor unit in a back muscle
B) a motor unit in a hand muscle
C) a motor unit in an eye muscle

Question 77

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

A) tetany.
B) treppe.
C) concentric.
D) isotonic.
E) isometric.

Question 78

Figure 9-2 Muscle Contractions
Use Figure 9-2 to answer the following questions:
What is the single response to each stimulus of a skeletal muscle called?

A) complete tetanus
B) incomplete tetanus
C) twitch
D) wave summation
E) treppe

Question 79

Figure 9-2 Muscle Contractions
Use Figure 9-2 to answer the following questions:
Why is there partial relaxation in graph (c)?

A) Calcium ion release is slow.
B) The muscle is starting to fatigue.
C) Stimulation intensity is fluctuating.
D) ATP reserves are cycling.
E) Nerve stimulation frequency is below maximum.

Question 80

When a muscle is stimulated repeatedly at a high rate, the amount of tension gradually increases to a steady maximum tension. This is called

A) incomplete tetanus.
B) complete tetanus.
C) a twitch.
D) wave summation.
E) recruitment.