Question 1

Which of the following is NOT a function of skeletal muscle?

Accepted Answer

A)   body movement
B)   maintenance of posture
C)   respiration
D)   constriction of organs
E)   production of heatF) A) and E)
G) C) and E)

Question 2

Tetanus of a muscle is thought to be caused by

Accepted Answer

A)   high calcium ion concentrations in the sarcoplasm.
B)   the rapid movement of sodium ions back into the sarcoplasmic reticulum.
C)   an increase in stimulus strength.
D)   increased temperature in the active muscle.
E)   decreased amounts of calcium ions in muscle tissue.F) A) and E)
G) B) and C)

Question 3

The condition of painful, spasmodic contractions of muscles is referred to as

Accepted Answer

A)   cramps.
B)   fibrositis.
C)   fibromyalgia.
D)   muscular dystrophy.
E)   paralysis.F) C) and D)
G) C) and E)

Question 4

What are caveolae?

Accepted Answer

A)   can rapidly develop action potentials
B)   shallow invaginations of cell membrane
C)   relatively constant tension maintained for a period of time
D)   intracellular cytoskeleton
E)   enzyme that removes phosphate from myosinF) A) and B)
G) None of the above

Question 5

-What does "A" represent on the diagram?

Accepted Answer

A)   threshold
B)   depolarization
C)   depolarization phase of action potential
D)   repolarization phase of action potentialE) All of the above
F) C) and D)

Question 6

In which type of respiration does lactic acid build up in muscle fibers?

Accepted Answer

A)   anaerobic respiration
B)   aerobic respiration
C)   both anaerobic and aerobic respirationD) B) and C)
E) A) and C)

Question 7

An isometric contraction is described as

Accepted Answer

A)   action potential frequency is high enough that no relaxation of muscle fibers occurs.
B)   a muscle produces constant tension during contraction.
C)   a muscle produces an increasing tension as the length remains constant.
D)   a muscle produces increasing tension as it shortens.
E)   a muscle produces tension, but the length of the muscle is increasing.F) B) and D)
G) A) and D)

Question 8

Multiple wave summation

Accepted Answer

A)   is a time during which the tissue cannot respond again.
B)   results in complete and incomplete tetanus.
C)   is a condition in which the muscle fiber only partially relaxes between contractions.
D)   is a condition in which stimuli occur so rapidly that there are no intervening relaxations.
E)   is a constant tension produced by muscles for long periods of time.F) C) and D)
G) A) and B)

Question 9

The active sites to which cross-bridges attach are found on the

Accepted Answer

A)   sarcoplasmic reticulum.
B)   actin myofilaments.
C)   Z disks.
D)   T tubules.
E)   myosin myofilaments.F) A) and B)
G) A) and C)

Question 10

Multiunit smooth muscle is located in the

Accepted Answer

A)   gastrocnemius.
B)   wall of the GI tract.
C)   wall of blood vessels.
D)   wall of the heart.
E)   reproductive system.F) All of the above
G) D) and E)

Question 11

When the myosin head flexes into a bend, pulling the actin filament along with it, this is called the

Accepted Answer

A)   action reaction.
B)   power stroke.
C)   recovery stroke.
D)   muscle tone.
E)   action potential.F) B) and C)
G) A) and E)

Question 12

Which of the following is part of a thin myofilament?

Accepted Answer

A)   ATP-binding site
B)   globular (G)  actin
C)   calcium
D)   myosin
E)   sarcolemmaF) B) and E)
G) A) and C)

Question 13

Smooth muscle is regulated by all of the following except

Accepted Answer

A)   the autonomic nervous system.
B)   neurotransmitters.
C)   the somatic nervous system.
D)   hormones.
E)   prostaglandins.F) A) and D)
G) C) and E)

Question 14

Complete tetanus

Accepted Answer

A)   is the time during which the tissue cannot respond again.
B)   results in complete and incomplete tetanus.
C)   is the condition in which the muscle fiber only partially relaxes between contractions.
D)   is the condition in which stimuli occur so rapidly that there are no intervening relaxations.
E)   is the constant tension produced by muscles for long periods of time.F) A) and B)
G) A) and C)

Question 15

Which type of respiration produces ATP molecules?

Accepted Answer

A)   anaerobic respiration
B)   aerobic respiration
C)   both anaerobic and aerobic respirationD) B) and C)
E) A) and C)

Question 16

The model that describes the contraction of the muscle is called the

Accepted Answer

A)   contraction cycle.
B)   power stroke.
C)   sliding filament model.
D)   slipping fibril mechanism.
E)   paddle model.F) All of the above
G) B) and E)

Question 17

What is the power stroke?

Accepted Answer

A)   a protein found along the groove of the F-actin double helix
B)   a T tubule and two adjacent terminal cisternae
C)   the combination of myosin heads with active sites on actin molecules
D)   the movement of myosin head while attached to actin myofilament
E)   after exercise, the oxygen taken in that exceeds the oxygen required for resting metabolismF) A) and E)
G) B) and E)

Question 18

Arrange these structures as they participate in excitation-contraction.

Accepted Answer

A)   T tubules, sarcolemma, calcium ions, sarcoplasmic reticulum
B)   calcium ions, T tubules, sarcolemma, sarcoplasmic reticulum
C)   sarcolemma, T tubules, sarcoplasmic reticulum, calcium ions
D)   sarcoplasmic reticulum, calcium ions, T tubules, sarcolemma
E)   sarcolemma, sarcoplasmic reticulum, calcium ions, T tubulesF) All of the above
G) A) and D)

Question 19

Aerobic exercise

Accepted Answer

A)   increases vascularity of muscle.
B)   develops fatigue-resistant fast-twitch fibers.
C)   can increase the efficiency of slow-twitch fibers.
D)   can increase the number of mitochondria in muscle cells.
E)   All of these choices are correct.F) None of the above
G) B) and C)

Question 20

Which of the following statements concerning fast-twitch muscle fibers is true?

Accepted Answer

A)   They split ATP rapidly.
B)   They have large deposits of myoglobin.
C)   They are well adapted to aerobic metabolism.
D)   They have a well-developed blood supply.
E)   They have many mitochondria.F) All of the above
G) None of the above

Exam 9: Muscular System: Histology and Physiology

Which of the following is part of a thin myofilament?

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What is the power stroke?

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What are caveolae?

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In which type of respiration does lactic acid build up in muscle fibers?

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Multiple wave summation

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Smooth muscle is regulated by all of the following except

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Which type of respiration produces ATP molecules?

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Which of the following is NOT a function of skeletal muscle?

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Aerobic exercise

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The active sites to which cross-bridges attach are found on the

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Which of the following statements concerning fast-twitch muscle fibers is true?

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Complete tetanus

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Tetanus of a muscle is thought to be caused by

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When the myosin head flexes into a bend, pulling the actin filament along with it, this is called the

Correct AnswerverifiedShow Answer

Arrange these structures as they participate in excitation-contraction.

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The condition of painful, spasmodic contractions of muscles is referred to as

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-What does "A" represent on the diagram?

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Multiunit smooth muscle is located in the

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The model that describes the contraction of the muscle is called the

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An isometric contraction is described as

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