Question 1

What happens when troponin and tropomyosin block the active sites of actin?

Accepted Answer

A)   The muscle produces a weak contraction.
B)   The muscle relaxes.
C)   The muscle contraction reaches peak tension.
D)   The muscle contraction increases tension.E) None of the above
F) A) and D)

Question 2

ATP is required for a power stroke to be repeated during the contraction cycle.

Accepted Answer

A) True 
 B)False

Question 3

The three types of myofilaments are thin, thick and elastic.

Accepted Answer

A) True 
 B)False

Question 4

The plasma membrane of a muscle cell is known as the:

Accepted Answer

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

Question 5

How does hypertrophy change a muscle? Briefly explain.

Accepted Answer

Hypertrophy is an in...

Question 6

Type I fibers lack:

Accepted Answer

A)   a blood supply.
B)   myoglobin.
C)   mitochondria.
D)   speed.E) A) and D)
F) B) and C)

Question 7

What does the depolarization of the transverse tubules (T -tubules)  promote?

Accepted Answer

A)   release of acetylcholine from vesicles in the motor neuron into the synaptic cleft
B)   binding of acetylcholine to ligand -gated sodium ion channels
C)   entry of sodium ions into the muscle fiber through voltage -gated sodium ion channels
D)   release of calcium from the sarcoplasmic reticulumE) A) and B)
F) All of the above

Question 8

When a skeletal muscle fiber contracts:

Accepted Answer

A)   Z discs move farther apart while the A bands shorten.
B)   the H zone and I bands narrow.
C)   the A bands shorten while the I bands lengthen.
D)   the H zone narrows while the I bands widen.E) C) and D)
F) B) and D)

Question 9

Describe the events of the relaxation period of a muscle twitch.

Accepted Answer

During relaxation, tension decreases as ...

Question 10

Which protein does NOT belong in a thin filament?

Accepted Answer

A)   troponin
B)   tropomyosin
C)   myosin
D)   actinE) A) and B)
F) A) and C)

Question 11

What do skeletal muscle tissue and cardiac muscle tissue share in common?

Accepted Answer

A)   Both skeletal and cardiac muscle tissues perform peristalsis.
B)   Both skeletal and cardiac muscle tissues possess intercalated discs.
C)   Both skeletal and cardiac muscle tissues are striated.
D)   Both skeletal and cardiac muscle tissues are voluntary.E) B) and D)
F) A) and B)

Question 12

What part of the myofibril shortens to produce contractions of the muscle fiber?

Accepted Answer

A)   myosin filaments
B)   A band
C)   sarcomere
D)   elastic filamentsE) B) and D)
F) A) and B)

Question 13

A muscle cell experiencing resting membrane potential is:

Accepted Answer

A)   propagating an action potential.
B)   more negatively charged on its exterior than in its interior.
C)   experiencing depolarization.
D)   polarized.E) None of the above
F) A) and B)

Question 14

Latrotoxin, produced by the poisonous black widow spider, increases the release of acetylcholine. How do muscle cells respond?

Accepted Answer

A)   Muscle cells will twitch irregularly when excess acetylcholine exists.
B)   Muscle cells will experience fused or complete tetanus when excess acetylcholine exists.
C)   Muscle cells will become paralyzed when excess acetylcholine exists.
D)   Muscle cells will experience a longer latent period when excess acetylcholine exists.E) B) and C)
F) A) and D)

Question 15

The fastest muscle contraction would be produced by a:

Accepted Answer

A)   type IIc fiber.
B)   type IIb fiber.
C)   type IIx fiber.
D)   type I fiber.E) A) and B)
F) C) and D)

Question 16

Describe the role of calcium in the crossbridge cycle of the sliding filament mechanism.

Accepted Answer

Calcium ions released from the sarcoplas...

Question 17

Define excitability.

Accepted Answer

Excitability is the ...

Question 18

A triad consists of:

Accepted Answer

A)   actin filaments, troponin, and tropomyosin.
B)   myosin filaments, myosin heads, and myosin tails.
C)   a transverse tubule (T -tubule)  and two terminal cisternae.
D)   a fascicle of skeletal muscle cells and its surrounding perimysium.E) C) and D)
F) None of the above

Question 19

Which of the following promotes the depolarization stage?

Accepted Answer

A)   opening of voltage -gated potassium ion channels and potassium ions exit the cell
B)   closure of voltage -gated sodium ion channels
C)   hydrolysis of ATP
D)   opening of voltage -gated sodium ion channels and sodium ions enter the cellE) B) and C)
F) C) and D)

Question 20

During excitation -contraction coupling, calcium ion concentration is highest in the:

Accepted Answer

A)   terminal cisterna.
B)   sarcolemma.
C)   sarcoplasmic reticulum.
D)   cytosol of the muscle fiber.E) C) and D)
F) None of the above

Exam 10: Muscle Tissue Physiology

Describe the events of the relaxation period of a muscle twitch.

Correct AnswerverifiedDuring relaxation, tension decreases as ...View AnswerShow Answer

Latrotoxin, produced by the poisonous black widow spider, increases the release of acetylcholine. How do muscle cells respond?

Correct AnswerverifiedShow Answer

Which of the following promotes the depolarization stage?

Correct AnswerverifiedShow Answer

What does the depolarization of the transverse tubules (T -tubules) promote?

Correct AnswerverifiedShow Answer

When a skeletal muscle fiber contracts:

Correct AnswerverifiedShow Answer

Type I fibers lack:

Correct AnswerverifiedShow Answer

What happens when troponin and tropomyosin block the active sites of actin?

Correct AnswerverifiedShow Answer

A muscle cell experiencing resting membrane potential is:

Correct AnswerverifiedShow Answer

During excitation -contraction coupling, calcium ion concentration is highest in the:

Correct AnswerverifiedShow Answer

Describe the role of calcium in the crossbridge cycle of the sliding filament mechanism.

Correct AnswerverifiedCalcium ions released from the sarcoplas...View AnswerShow Answer

Define excitability.

Correct AnswerverifiedExcitability is the ...View AnswerShow Answer

ATP is required for a power stroke to be repeated during the contraction cycle.

Correct AnswerverifiedShow Answer

What part of the myofibril shortens to produce contractions of the muscle fiber?

Correct AnswerverifiedShow Answer

The three types of myofilaments are thin, thick and elastic.

Correct AnswerverifiedShow Answer

What do skeletal muscle tissue and cardiac muscle tissue share in common?

Correct AnswerverifiedShow Answer

A triad consists of:

Correct AnswerverifiedShow Answer

Which protein does NOT belong in a thin filament?

Correct AnswerverifiedShow Answer

The fastest muscle contraction would be produced by a:

Correct AnswerverifiedShow Answer

How does hypertrophy change a muscle? Briefly explain.

Correct AnswerverifiedHypertrophy is an in...View AnswerShow Answer

The plasma membrane of a muscle cell is known as the:

Correct AnswerverifiedShow Answer

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During relaxation, tension decreases as ...
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What does the depolarization of the transverse tubules (T ^-tubules) promote?

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During excitation ^-contraction coupling, calcium ion concentration is highest in the:

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Calcium ions released from the sarcoplas...
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Excitability is the ...
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Hypertrophy is an in...
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Correct Answer
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