Question 1

Which muscle type contains actin and myosin?

Accepted Answer

A)   smooth muscle only (single -unit or multi -unit) 
B)   skeletal and smooth muscle only
C)   skeletal, smooth, and cardiac muscle
D)   skeletal muscle only
E)   smooth and cardiac muscle onlyF) A) and D)
G) A) and B)

Question 2

Binding of ATP to myosin increases myosin's affinity for actin.

Accepted Answer

A) True 
 B)False

Question 3

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

Accepted Answer

A)   conformational change that occurs as the myosin head changes from the high to low energy state
B)   binding of tropomyosin to myosin
C)   binding of ATP to myosin
D)   binding of ATP to actin
E)   binding of the troponin complex to actinF) B) and E)
G) A) and E)

Question 4

-What is the structure indicated by the number 3 in Figure 12.1 and what is its functional significance?

Accepted Answer

A)   A band : length of myosin attached to an M line
B)   M line : where the tails of the myosin molecules are bound to one another
C)   Z line : anchors the thin filaments together
D)   sarcomere : the functional unit of muscle contraction whose length is changed as a muscle shortens and lengthens
E)   H zone : area of myosin not overlapped by actinF) C) and D)
G) A) and B)

Question 5

What is the protein component of the thin filament that blocks the myosin -binding site on the actin monomer?

Accepted Answer

A)   sarcoplasmic reticulum
B)   tropomyosin
C)   transverse tubule
D)   troponin
E)   actinF) A) and E)
G) B) and D)

Question 6

Energy in the form of ATP is essential to the contractile process. Describe the cellular sources of energy for skeletal muscle fibers and how those energy sources play a role maintaining muscle activity at low -and high -intensities of activity.

Accepted Answer

Energy in the form of ATP is required fo...

Question 7

In smooth muscle, the structures analogous to Z lines in skeletal muscle are called

Accepted Answer

A)   MLCK.
B)   gap junctions.
C)   intercalated disks.
D)   dense bodies.
E)   S lines.F) None of the above
G) A) and B)

Question 8

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

Accepted Answer

A)   titin cycling
B)   crossbridge cycling
C)   the sliding -filament model
D)   sarcomeric facilitation
E)   Z line interactionF) B) and D)
G) B) and C)

Question 9

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

Accepted Answer

A)   sarcomeres
B)   actin and myosin
C)   motor end plate
D)   sarcoplasmic reticulum
E)   tendonsF) A) and E)
G) All of the above

Question 10

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

Accepted Answer

A)   fewer capillaries
B)   poor ability to produce ATP in the absence of oxygen
C)   high capacity for lactic acid production
D)   readily fatigable
E)   absence of myoglobinF) A) and B)
G) A) and C)

Question 11

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

Accepted Answer

A)   Z line
B)   A band
C)   M line
D)   H zone
E)   I bandF) C) and E)
G) A) and D)

Question 12

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

Accepted Answer

A)   fast oxidative skeletal muscle
B)   cardiac muscle
C)   slow oxidative skeletal muscle
D)   smooth muscle
E)   fast glycolytic skeletal muscleF) C) and D)
G) A) and E)

Question 13

-What is the structure indicated by the number 1 in Figure 12.1 and what is its functional significance

Accepted Answer

A)   A band : length of myosin attached to an M line
B)   H zone : area of myosin not overlapped by actin
C)   Z line : anchors the thin filaments together
D)   M line : where the tails of the myosin molecules are bound to one another
E)   sarcomere : the functional unit of muscle contraction whose length is changed as a muscle shortens and lengthensF) A) and B)
G) All of the above

Question 14

Spontaneous depolarization of smooth muscle cells is mediated by pacemaker cells.

Accepted Answer

A) True 
 B)False

Question 15

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.

Accepted Answer

A)   random
B)   asynchronous
C)   asymmetrical
D)   symmetrical
E)   synchronousF) B) and D)
G) B) and C)

Question 16

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

Accepted Answer

A)   The amount of calcium bound to troponin decreases.
B)   A myosin -binding site on the actin molecule is blocked by tropomyosin.
C)   The binding of calcium to a low -affinity site closes sarcoplasmic reticulum calcium channels.
D)   Sarcolemmal calcium channels open to allow the efflux of calcium.
E)   A calcium pump actively removes calcium.F) A) and D)
G) All of the above

Question 17

Which protein binds calcium in smooth muscle cells?

Accepted Answer

A)   tropomyosin
B)   myosin light -chain kinase
C)   troponin
D)   calmodulin
E)   titinF) A) and D)
G) A) and C)

Question 18

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

Accepted Answer

A)   breaking of the actin myosin complex
B)   binding of actin to myosin
C)   power stroke
D)   cocking of the myosin head
E)   development of rigorF) C) and D)
G) A) and E)

Question 19

What is the antagonistic muscle to the triceps?

Accepted Answer

A)   brachialis
B)   coracobrachialis
C)   quadriceps
D)   biceps
E)   posterior deltoidF) B) and E)
G) A) and E)

Question 20

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

Accepted Answer

A)   Repeated action potentials along the same neuron can lead to neuromuscular fatigue.
B)   Compression of muscle during contraction can reduce blood flow to the muscle.
C)   The crossbridges can become resistant to ATP.
D)   Glycolytic fibers produce lactic acid and inhibit enzyme activity with their hydrogen ion.
E)   Oxidative fibers can be depleted of glycogen, their primary energy source.F) None of the above
G) A) and E)

Exam 12: Muscle Physiology

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which protein binds calcium in smooth muscle cells?

Correct AnswerverifiedShow Answer

In smooth muscle, the structures analogous to Z lines in skeletal muscle are called

Correct AnswerverifiedShow Answer

-What is the structure indicated by the number 1 in Figure 12.1 and what is its functional significance

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

What is the antagonistic muscle to the triceps?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which muscle type contains actin and myosin?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Spontaneous depolarization of smooth muscle cells is mediated by pacemaker cells.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Binding of ATP to myosin increases myosin's affinity for actin.

Correct AnswerverifiedShow Answer

Energy in the form of ATP is essential to the contractile process. Describe the cellular sources of energy for skeletal muscle fibers and how those energy sources play a role maintaining muscle activity at low -and high -intensities of activity.

Correct AnswerverifiedEnergy in the form of ATP is required fo...View AnswerShow Answer

What is the protein component of the thin filament that blocks the myosin -binding site on the actin monomer?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

-What is the structure indicated by the number 3 in Figure 12.1 and what is its functional significance?

Correct AnswerverifiedShow Answer

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Energy in the form of ATP is required fo...
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