Question 1

What is an annulospiral ending?

Accepted Answer

A)   sensory endings in the Golgi tendon organ that detect muscle tension
B)   a structure in the utricle that contains hair cells
C)   a structure in the semicircular canals that contains hair cells
D)   sensory endings in the muscle spindle that detect muscle length
E)   a structure in the cochlea that contains hair cellsF) C) and D)
G) B) and D)

Question 2

Once a skeletal muscle cell begins to shorten during an isotonic twitch contraction,

Accepted Answer

A)   the muscle will stop shortening once the force is greater than the load.
B)   the muscle will continue to shorten until the force generated by the muscle stops increasing.
C)   the amount of force generated by the muscle will continue to increase.
D)   the amount of force generated by the muscle will start to decrease.
E)   the amount of force generated by the muscle will remain constant.F) A) and B)
G) B) and C)

Question 3

What is an increase in the number of active motor units that would increase the force developed by a skeletal muscle called?

Accepted Answer

A)   tetanus
B)   recruitment
C)   length -tension relationship
D)   treppe
E)   summationF) A) and E)
G) B) and C)

Question 4

Increases in the amount of cytoplasmic calcium required to initiate a muscle contraction are mediated by the coupling between a _______on the T tubule and a__________ on the membrane of the sarcoplasmic reticulum.

Accepted Answer

A)   calcium pump : ryanodine receptor 
B)   dihydropyridine receptor : calcium pump
C)   ryanodine receptor : calcium pump
D)   dihydropyridine receptor : ryanodine receptor
E)   calcium -induced calcium release channel : dihydropyridine receptorF) None of the above
G) D) and E)

Question 5

Which of the following appears as light bands under the microscope?

Accepted Answer

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

Question 6

Which of the following is NOT a specialization observed at the neuromuscular junction?

Accepted Answer

A)   The motor end plate is relatively large compared with other synapses.
B)   The terminal bouton fans out over a wide area of the sarcolemma.
C)   There is a high density of acetylcholine receptors in the motor end plate.
D)   Each muscle fiber is innervated by multiple motor neurons.
E)   Every action potential that reaches the axon terminal of the motor neuron will generate an action potential in the healthy muscle fiber.F) All of the above
G) A) and B)

Question 7

Receptor types at the motor end plate are (muscarinic / nicotinic) cholinergic receptors.

Accepted Answer

The answer of Receptor types at the motor end plate...

Question 8

During skeletal muscle contraction, multiple crossbridge cycles are occurring between the same thick and thin filament. Which of the following best describes this process?

Accepted Answer

A)   No more than one myosin head detaches from the thin filament at the same time.
B)   Tropomyosin only exposes one binding site on actin at a time allowing only one crossbridge to form with actin at a given time.
C)   No more than one myosin head links to the thin filament at the same time.
D)   Crossbridge cycling is highly synchronized between a certain thick and thin filament.
E)   Crossbridge cycling is asynchronous between a certain thick and thin filament.F) C) and E)
G) None of the above

Question 9

What is the region of thin filaments that has no overlap with thick filaments called?

Accepted Answer

A)   Z line
B)   A band
C)   I band
D)   M line
E)   H zoneF) All of the above
G) B) and C)

Question 10

The binding of calcium to troponin will directly allow which of the following?

Accepted Answer

A)   the hydrolysis of ATP
B)   the binding of ATP to myosin
C)   the movement of tropomyosin, thereby exposing the myosin -binding site on the actin molecule
D)   the further release of calcium into the cytoplasm
E)   the movement of tropomyosin, thereby exposing the actin -binding site on the myosin moleculeF) A) and C)
G) A) and E)

Question 11

Action potentials in cardiac muscle last longer than action potentials in skeletal muscle.

Accepted Answer

A) True 
 B)False

Question 12

Which of the following is a property of isotonic skeletal muscle contraction?

Accepted Answer

A)   There is a slow increase in force with no change in muscle length.
B)   Load is less than the force generated by the muscle.
C)   There is a rapid increase in force with no change in muscle length.
D)   Load is greater than the force generated by the muscle.
E)   Muscle length will be increased by contraction.F) A) and B)
G) All of the above

Question 13

The mechanism responsible for the size principle involves

Accepted Answer

A)   larger motor neurons that innervate the greatest number of muscle cells and reach threshold easier than smaller neurons.
B)   smaller motor units that contain the greatest number of muscle cells and reach threshold easier than larger neurons.
C)   smaller sympathetic neurons that contain the least number of muscle cells and reach threshold easier than larger neurons.
D)   larger sympathetic neurons that contain the greatest number of muscle cells and reach threshold easier than smaller neurons.
E)   smaller motor neurons that innervate the least number of muscle cells and reach threshold easier than larger neurons.F) None of the above
G) A) and B)

Question 14

The fundamental repeating unit of the myofibril, called a ___________, gives skeletal muscle its striated appearance and is bordered by ________.

Accepted Answer

A)   crossbridge : Z lines
B)   sarcomere : I bands
C)   sarcomere : Z lines
D)   crossbridge : A bands
E)   sarcomere : M linesF) A) and C)
G) A) and B)

Question 15

Which of the following generates the mechanical force of a muscle through crossbridge cycling?

Accepted Answer

A)   motor end plate
B)   sarcoplasmic reticulum
C)   sarcomeres
D)   tendons
E)   actin and myosinF) C) and E)
G) B) and D)

Question 16

Which of the following does NOT influence the force generated by an individual muscle fiber?

Accepted Answer

A)   frequency of stimulation
B)   summation
C)   length at onset of contraction
D)   recruitment
E)   fiber diameterF) B) and E)
G) A) and B)

Question 17

Ryanodine receptors are calcium channels in the sarcoplasmic reticulum.

Accepted Answer

A) True 
 B)False

Question 18

What are the elastic fibers that anchor thick filaments in place?

Accepted Answer

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

Question 19

Relative to the triceps muscle, the biceps is its

Accepted Answer

A)   agonist.
B)   antagonist.
C)   insertion.
D)   origin.
E)   abductor.F) A) and D)
G) A) and C)

Question 20

Troponin is a complex of three proteins that bind to tropomyosin, calcium, and

Accepted Answer

A)   troponin.
B)   transverse tubule.
C)   sarcoplasmic reticulum.
D)   tropomyosin.
E)   actin.F) A) and B)
G) B) and E)

Exam 12: Muscle Physiology

Which of the following generates the mechanical force of a muscle through crossbridge cycling?

Correct AnswerverifiedShow Answer

Relative to the triceps muscle, the biceps is its

Correct AnswerverifiedShow Answer

What is an increase in the number of active motor units that would increase the force developed by a skeletal muscle called?

Correct AnswerverifiedShow Answer

The fundamental repeating unit of the myofibril, called a ___________, gives skeletal muscle its striated appearance and is bordered by ________.

Correct AnswerverifiedShow Answer

Which of the following is a property of isotonic skeletal muscle contraction?

Correct AnswerverifiedShow Answer

Which of the following does NOT influence the force generated by an individual muscle fiber?

Correct AnswerverifiedShow Answer

Action potentials in cardiac muscle last longer than action potentials in skeletal muscle.

Correct AnswerverifiedShow Answer

Ryanodine receptors are calcium channels in the sarcoplasmic reticulum.

Correct AnswerverifiedShow Answer

Which of the following appears as light bands under the microscope?

Correct AnswerverifiedShow Answer

Which of the following is NOT a specialization observed at the neuromuscular junction?

Correct AnswerverifiedShow Answer

During skeletal muscle contraction, multiple crossbridge cycles are occurring between the same thick and thin filament. Which of the following best describes this process?

Correct AnswerverifiedShow Answer

The mechanism responsible for the size principle involves

Correct AnswerverifiedShow Answer

Receptor types at the motor end plate are (muscarinic / nicotinic) cholinergic receptors.

Correct AnswerverifiedShow Answer

What is an annulospiral ending?

Correct AnswerverifiedShow Answer

The binding of calcium to troponin will directly allow which of the following?

Correct AnswerverifiedShow Answer

Once a skeletal muscle cell begins to shorten during an isotonic twitch contraction,

Correct AnswerverifiedShow Answer

What are the elastic fibers that anchor thick filaments in place?

Correct AnswerverifiedShow Answer

Increases in the amount of cytoplasmic calcium required to initiate a muscle contraction are mediated by the coupling between a _______on the T tubule and a__________ on the membrane of the sarcoplasmic reticulum.

Correct AnswerverifiedShow Answer

What is the region of thin filaments that has no overlap with thick filaments called?

Correct AnswerverifiedShow Answer

Troponin is a complex of three proteins that bind to tropomyosin, calcium, and

Correct AnswerverifiedShow Answer

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The fundamental repeating unit of the myofibril, called a ___, gives skeletal muscle its striated appearance and is bordered by .

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Increases in the amount of cytoplasmic calcium required to initiate a muscle contraction are mediated by the coupling between a _on the T tubule and a____ on the membrane of the sarcoplasmic reticulum.

Correct Answer
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