Question 1

Which of the following is NOT true of muscular atrophy?

Accepted Answer

A)   It is irreversible.
B)   It can be caused by disuse.
C)   It can be caused by denervation.
D)   Transcutaneous stimulation can help prevent it.
E)   Muscle fibers are replaced by connective tissue.F) A) and E)
G) C) and D)

Question 2

Myasthenia gravis results from the destruction of acetylcholine receptors at the neuromuscular junction, but treatment involves medications that reduce acetylcholinesterase activity. Which statement best explains the effectiveness of these medications?

Accepted Answer

A)   The antibodies destroy some but not all of the acetylcholine receptors, so reducing acetylcholinesterase activity increases the likelihood that acetylcholine will bind to the remaining receptors.
B)   Acetylcholinesterase is the substance that destroys the receptors as well, so reducing its activity increases the number of acetylcholine receptors.
C)   Acetylcholinesterase breaks down the acetylcholine to a substance that can bind to the damaged receptors.
D)   The antibodies that destroy the acetylcholine receptors are less likely to work if acetylcholinesterase is present.E) A) and C)
F) C) and D)

Question 3

-What does "C" represent on the diagram?

Accepted Answer

A)   Threshold
B)   Depolarization
C)   Depolarization phase of action potential
D)   Repolarization phase of action potentialE) A) and B)
F) None of the above

Question 4

If one nerve stimulus arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch, the most likely result will be ________.

Accepted Answer

A)   fatigue
B)   spasm
C)   incomplete tetanus
D)   complete tetanus
E)   flaccid paralysisF) B) and D)
G) B) and C)

Question 5

A myofibril is the

Accepted Answer

A)   plasma membrane of a muscle fiber.
B)   cytoplasm of a muscle fiber.
C)   structural and functional unit of the skeletal muscle fiber.
D)   contractile thread that extends the length of the muscle fiber.
E)   protein strand composed of actin.F) C) and D)
G) B) and C) D

Question 6

ATPase is found in

Accepted Answer

A)   F-actin strands.
B)   G-actin globular units.
C)   myosin heads.
D)   tropomyosin grooves.
E)   troponin molecules.F) C) and D)
G) C) and E)

Question 7

A lack of glycolytic enzymes within skeletal muscle fibers would impair which type of ATP-yielding process?

Accepted Answer

A)   Anaerobic respiration
B)   Aerobic respiration
C)   Both anaerobic respiration and aerobic respiration are correct.D) A) and C)
E) A) and B)

Question 8

Arrange the following list of biochemical events in the correct sequence.
(1)  An action potential is conducted deep into the muscle fiber by the T tubule.
(2)  Calcium ions bind to troponin.
(3)  The membranes of the sarcoplasmic reticulum become more permeable to calcium ions.
(4)  Calcium ions diffuse into the sarcoplasm around the myofibril.
(5)  The troponin-tropomyosin complex moves exposing active sites.

Accepted Answer

A)   1, 5, 2, 3, 4
B)   1, 3, 4, 2, 5
C)   1, 2, 3, 4, 5
D)   1, 3, 2, 5, 4
E)   1, 4, 3, 2, 5F) A) and C)
G) A) and B)

Question 9

A skeletal muscle generates the greatest tension when it is

Accepted Answer

A)   greatly stretched before being stimulated.
B)   partially stretched before being stimulated.
C)   fully relaxed before being stimulated.
D)   well-rested and low in creatine phosphate.
E)   high in lactate concentration.F) B) and D)
G) A) and E)

Question 10

Which of the following descriptions best represents the appearance of the sarcomere during peak contraction?

Accepted Answer

A)   The H zone is eliminated, and the I bands are very thin.
B)   The width of the A band is slightly less than the width of the I band.
C)   The H zone is equivalent to one-third of the length of the A band.
D)   The I bands and A bands are of equal widths.E) None of the above
F) A) and B)

Question 11

-What does "D" represent on the diagram?

Accepted Answer

A)   Threshold
B)   Depolarization
C)   Depolarization phase of action potential
D)   Repolarization phase of action potentialE) A) and C)
F) B) and D)

Question 12

Skeletal muscle fibers

Accepted Answer

A)   possess striations.
B)   can contract but are not extensible or excitable.
C)   do not require nerve innervation to contract.
D)   increase dramatically in number after birth.
E)   are found in the walls of the stomach.F) A) and B)
G) A) and C)

Question 13

In excitation-contraction coupling,

Accepted Answer

A)   Ca2+ must bind with myosin to expose active sites on actin.
B)   myosin heads bind to exposed active sites on actin.
C)   cross-bridges form between myosin heads and Ca2+.
D)   movement of the troponin-tropomyosin complex causes actin myofilaments to slide.
E)   ATP binds to actin myofilaments.F) D) and E)
G) A) and B)

Question 14

Identify the statement concerning general functional characteristics of muscle that is true.

Accepted Answer

A)   Muscle tissue shortens forcefully but lengthens passively.
B)   Muscle tissue shortens passively but lengthens forcefully.
C)   Muscle tissue can get shorter, but cannot get longer.
D)   Muscle tissue can get longer, but cannot get shorter.
E)   None of these statements are true.F) C) and D)
G) A) and E)

Question 15

The elevated oxygen consumption relative to activity level after exercise has ended is called

Accepted Answer

A)   oxygen deficit.
B)   oxygen debt.
C)   oxygen repayment.
D)   excess post-exercise oxygen consumption.
E)   anaerobic recovery.F) A) and C)
G) B) and D)

Question 16

-The figure illustrates a detailed drawing of the neuromuscular junction. What does "B" represent?

Accepted Answer

A)   Synaptic vesicles
B)   Synaptic cleft
C)   Sarcolemma
D)   Presynaptic terminal
E)   Postsynaptic membraneF) None of the above
G) A) and D) D

Question 17

Curare blocks acetylcholine receptors at the motor end plate. This would result in

Accepted Answer

A)   increased stimulation of the muscle.
B)   more acetylcholinesterase production.
C)   lack of Ca2+ uptake by the muscle fiber.
D)   inability of the muscle fiber to respond to nervous stimulation.
E)   sustained contraction of the muscle.F) C) and D)
G) None of the above

Question 18

One ATP molecule is required for

Accepted Answer

A)   formation of the cross-bridge.
B)   movement of the cross-bridge.
C)   release of the cross-bridge.
D)   formation of the cross-bridge and for movement of the cross-bridge.
E)   formation of the cross-bridge, for movement of the cross-bridge, and for release of the cross-bridge.F) B) and E)
G) A) and D)

Question 19

Skeletal muscle develops from cells called

Accepted Answer

A)   fascicles.
B)   myoblasts.
C)   myofibrils.
D)   myotomes.
E)   fasciculi.F) All of the above
G) C) and E) B

Question 20

Which of the following statements best predicts the effect of a substance that blocks creatine kinase activity?

Accepted Answer

A)   ATP production from creatine phosphate would decrease.
B)   ATP production from creatine phosphate would increase.
C)   ADP production from creatine phosphate would decrease.
D)   ADP production from creatine phosphate would increase.E) All of the above
F) A) and B)

Exam 9: Muscular System: Histology and Physiology

Which of the following is NOT true of muscular atrophy?

Correct Answer
verified

Myasthenia gravis results from the destruction of acetylcholine receptors at the neuromuscular junction, but treatment involves medications that reduce acetylcholinesterase activity. Which statement best explains the effectiveness of these medications?

Correct Answer
verified

-What does "C" represent on the diagram?

Correct Answer
verified

If one nerve stimulus arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch, the most likely result will be ________.

Correct Answer
verified

A myofibril is the

Correct Answer
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D

ATPase is found in

Correct Answer
verified

A lack of glycolytic enzymes within skeletal muscle fibers would impair which type of ATP-yielding process?

Correct Answer
verified

Correct Answer
verified

A skeletal muscle generates the greatest tension when it is

Correct Answer
verified

Which of the following descriptions best represents the appearance of the sarcomere during peak contraction?

Correct Answer
verified

-What does "D" represent on the diagram?

Correct Answer
verified

Skeletal muscle fibers

Correct Answer
verified

In excitation-contraction coupling,

Correct Answer
verified

Identify the statement concerning general functional characteristics of muscle that is true.

Correct Answer
verified

The elevated oxygen consumption relative to activity level after exercise has ended is called

Correct Answer
verified

-The figure illustrates a detailed drawing of the neuromuscular junction. What does "B" represent?

Correct Answer
verified
D

Curare blocks acetylcholine receptors at the motor end plate. This would result in

Correct Answer
verified

One ATP molecule is required for

Correct Answer
verified

Skeletal muscle develops from cells called

Correct Answer
verified
B

Which of the following statements best predicts the effect of a substance that blocks creatine kinase activity?

Correct Answer
verified

Exam 9: Muscular System: Histology and Physiology

Which of the following is NOT true of muscular atrophy?

Correct AnswerverifiedShow Answer

Myasthenia gravis results from the destruction of acetylcholine receptors at the neuromuscular junction, but treatment involves medications that reduce acetylcholinesterase activity. Which statement best explains the effectiveness of these medications?

Correct AnswerverifiedShow Answer

-What does "C" represent on the diagram?

Correct AnswerverifiedShow Answer

If one nerve stimulus arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch, the most likely result will be ________.

Correct AnswerverifiedShow Answer

A myofibril is the

Correct AnswerverifiedD

ATPase is found in

Correct AnswerverifiedShow Answer

A lack of glycolytic enzymes within skeletal muscle fibers would impair which type of ATP-yielding process?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A skeletal muscle generates the greatest tension when it is

Correct AnswerverifiedShow Answer

Which of the following descriptions best represents the appearance of the sarcomere during peak contraction?

Correct AnswerverifiedShow Answer

-What does "D" represent on the diagram?

Correct AnswerverifiedShow Answer

Skeletal muscle fibers

Correct AnswerverifiedShow Answer

In excitation-contraction coupling,

Correct AnswerverifiedShow Answer

Identify the statement concerning general functional characteristics of muscle that is true.

Correct AnswerverifiedShow Answer

The elevated oxygen consumption relative to activity level after exercise has ended is called

Correct AnswerverifiedShow Answer

-The figure illustrates a detailed drawing of the neuromuscular junction. What does "B" represent?

Correct AnswerverifiedD

Curare blocks acetylcholine receptors at the motor end plate. This would result in

Correct AnswerverifiedShow Answer

One ATP molecule is required for

Correct AnswerverifiedShow Answer

Skeletal muscle develops from cells called

Correct AnswerverifiedB

Which of the following statements best predicts the effect of a substance that blocks creatine kinase activity?

Correct AnswerverifiedShow Answer

Correct Answer
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D

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D

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B

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