Question 1

The time between application of the stimulus to a motor neuron and the beginning of contraction is called the ________ phase.

Accepted Answer

A)   contraction
B)   relaxation
C)   latent or lag
D)   refractory
E)   thresholdF) A) and B)
G) A) and C)

Question 2

-What does "E" represent on the diagram?

Accepted Answer

A)   Myosin myofilament
B)   Actin myofilament
C)   Sarcomere
D)   Z disk
E)   Cross-bridgeF) All of the above
G) A) and B)

Question 3

-What does "D" represent on the diagram?

Accepted Answer

A)   Myosin myofilament
B)   Actin myofilament
C)   Sarcomere
D)   Z disk
E)   Cross-bridgeF) A) and E)
G) A) and B)

Question 4

Which type of muscle tissue causes contraction of the heart?

Accepted Answer

A)   Skeletal muscle
B)   Smooth muscle
C)   Cardiac muscleD) B) and C)
E) None of the above

Question 5

Which of the following conditions in muscle fibers would contribute to muscle fatigue?

Accepted Answer

A)   The emotional state of an individual
B)   Depletion of ATP reserves
C)   Inability of the motor neuron to produce sufficient quantities of acetylcholine
D)   Depletion of neurotransmitter
E)   Blocked receptors in the postsynaptic membraneF) D) and E)
G) A) and B)

Question 6

Physiological contracture

Accepted Answer

A)   occurs when muscles are resting.
B)   is a condition in which cross-bridges cannot release.
C)   is caused by an abundance of ATP in muscle fibers.
D)   results when muscles are well exercised.
E)   results when the neurotransmitter remains in the receptor.F) B) and C)
G) A) and E)

Question 7

As you are lifting a box, someone places extra weight on top of it. For your muscle to continue contracting and lifting the box, the muscle must

Accepted Answer

A)   recruit more muscle fibers.
B)   lower its threshold.
C)   reduce its wave summation.
D)   shift from isometric to isotonic contraction.
E)   shift from slow-twitch to fast-twitch mode.F) D) and E)
G) A) and B)

Question 8

A sarcomere 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 or myosin.F) C) and E)
G) B) and D)

Question 9

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) All of the above
G) B) and D)

Question 10

-What does "B" represent on the diagram?

Accepted Answer

A)   Myosin myofilament
B)   Actin myofilament
C)   Sarcomere
D)   Z disk
E)   Cross-bridgeF) B) and C)
G) C) and D)

Question 11

List the following structures in order from smallest to largest.
(1)  Muscle fiber
(2)  Myofilament
(3)  Myofibril
(4)  Muscle fascicle

Accepted Answer

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

Question 12

Which of the following structures contains the other four items listed?

Accepted Answer

A)   Postsynaptic membrane
B)   Presynaptic terminal
C)   Synaptic cleft
D)   Neuromuscular junction
E)   Receptors on postsynaptic membraneF) C) and D)
G) A) and C)

Question 13

Rigor mortis occurs after death because

Accepted Answer

A)   cross-bridges form but can't release.
B)   Ca2+ is actively transported back to the sarcoplasmic reticulum.
C)   anaerobic respiration is occurring.
D)   myosin levels decline at death.
E)   cross-bridges never form.F) C) and D)
G) B) and C)

Question 14

The training regimen of a competitive weight lifter is designed partly to

Accepted Answer

A)   convert certain muscles with parallel muscle fascicles into muscles with non-parallel muscle fascicles.
B)   increase the average number of myofibrils per muscle fiber.
C)   convert fast muscle fibers to slow muscle fibers.
D)   increase the size of his motor units.
E)   lower the threshold for muscle stimulation.F) C) and D)
G) B) and C)

Question 15

A concentric 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 during contraction.
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 C)
G) B) and E)

Question 16

In order for muscle relaxation to occur,

Accepted Answer

A)   Ca2+ must be transported to troponin.
B)   power strokes slow down.
C)   the active sites on actin must be blocked.
D)   Na+ must be actively transported to troponin.
E)   the active sites on myosin must be uncovered.F) None of the above
G) B) and D)

Question 17

Smooth muscle and cardiac muscle are similar in that they both

Accepted Answer

A)   are under involuntary control.
B)   are striated.
C)   are widely distributed in the body.
D)   have multiple nuclei.
E)   are under voluntary control.F) B) and D)
G) B) and E)

Question 18

T tubules are invaginations of the

Accepted Answer

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

Question 19

Each ________ includes a Z disc and extends from each side of the Z disc to the ends of the myosin myofilaments.

Accepted Answer

A)   anisotropic band or A band
B)   isotropic band or I band
C)   muscle fiber
D)   sarcomereE) B) and C)
F) All of the above

Question 20

Lack of acetylcholinesterase in the synaptic cleft would result in

Accepted Answer

A)   a decrease in acetylcholine production by the motor neuron.
B)   continuous stimulation of the postsynaptic membrane.
C)   rapid degradation of acetylcholine.
D)   relaxation of the muscle.
E)   continuous stimulation of the presynaptic membrane.F) B) and E)
G) A) and B)

Exam 9: Muscular System: Histology and Physiology

-What does "D" represent on the diagram?

Correct AnswerverifiedShow Answer

The training regimen of a competitive weight lifter is designed partly to

Correct AnswerverifiedShow Answer

Lack of acetylcholinesterase in the synaptic cleft would result in

Correct AnswerverifiedShow Answer

-What does "E" represent on the diagram?

Correct AnswerverifiedShow Answer

Which type of muscle tissue causes contraction of the heart?

Correct AnswerverifiedShow Answer

An isometric contraction is described as

Correct AnswerverifiedShow Answer

Which of the following conditions in muscle fibers would contribute to muscle fatigue?

Correct AnswerverifiedShow Answer

Rigor mortis occurs after death because

Correct AnswerverifiedShow Answer

Each ________ includes a Z disc and extends from each side of the Z disc to the ends of the myosin myofilaments.

Correct AnswerverifiedShow Answer

Which of the following structures contains the other four items listed?

Correct AnswerverifiedShow Answer

Physiological contracture

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Smooth muscle and cardiac muscle are similar in that they both

Correct AnswerverifiedShow Answer

A concentric contraction is described as

Correct AnswerverifiedShow Answer

List the following structures in order from smallest to largest. (1) Muscle fiber (2) Myofilament (3) Myofibril (4) Muscle fascicle

Correct AnswerverifiedShow Answer

T tubules are invaginations of the

Correct AnswerverifiedShow Answer

As you are lifting a box, someone places extra weight on top of it. For your muscle to continue contracting and lifting the box, the muscle must

Correct AnswerverifiedShow Answer

The time between application of the stimulus to a motor neuron and the beginning of contraction is called the ________ phase.

Correct AnswerverifiedShow Answer

In order for muscle relaxation to occur,

Correct AnswerverifiedShow Answer

-What does "B" represent on the diagram?

Correct AnswerverifiedShow Answer

A sarcomere is the

Correct AnswerverifiedShow Answer

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