Question 1

(Single- unit / Multi- unit)smooth muscle contains pacemaker cells.

Accepted Answer

The answer of (Single- unit / Multi- unit)smooth muscle contains...

Question 2

The mechanism responsible for the size principle involves

Accepted Answer

A)  larger sympathetic neurons that contain the greatest number of muscle cells and reach threshold easier than smaller neurons.
B)  smaller motor neurons that innervate the least number of muscle cells and reach threshold easier than larger neurons.
C)  larger motor neurons that innervate the greatest number of muscle cells and reach threshold easier than smaller neurons.
D)  smaller motor units that contain the greatest number of muscle cells and reach threshold easier than larger neurons.
E)  smaller sympathetic neurons that contain the least number of muscle cells and reach threshold easier than larger neurons.F) A) and D)
G) A) and E)

Question 3

Which of the following is the voltage sensor that initiates an increase in cytoplasmic calcium in response to an action potential?

Accepted Answer

A)  dihydropyridine receptor
B)  sodium channel
C)  calcium pump
D)  calcium- induced calcium release channel
E)  ryanodine receptorF) B) and C)
G) B) and E)

Question 4

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

Accepted Answer

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

Question 5

The two types of sensory endings found in muscle spindles are the annulospiral endings and

Accepted Answer

A)  free endings.
B)  Ruffini's corpuscle.
C)  Pacinian corpuscle.
D)  Merkel's disks.
E)  flower- spray endings.F) B) and E)
G) A) and B)

Question 6

The tension produced during skeletal muscle contraction can be increased by all of the following EXCEPT

Accepted Answer

A)  initiating the contraction when the muscle is at its optimum length.
B)  increasing the frequency of action potentials in the muscle fiber.
C)  increasing the frequency of action potentials in the motor neuron innervating the muscle.
D)  increasing the load on the muscle.
E)  recruiting motor units.F) A) and E)
G) C) and D)

Question 7

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

Accepted Answer

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

Question 8

Some muscle cells have pacemaker activity. These include

Accepted Answer

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

Question 9

Oxidative phosphorylation is the primary energy source for cardiac muscle.

Accepted Answer

A) True 
 B)False

Question 10

The decreased ability of a muscle to maintain a constant force of contraction during repetitive stimulation is called what?

Accepted Answer

A)  fatigue
B)  wasting
C)  treppe
D)  tetanus
E)  O2 depletionF) B) and C)
G) A) and E)

Question 11

Which type of skeletal muscle fiber fatigues rapidly?

Accepted Answer

A)  fast
B)  glycolytic
C)  oxidative
D)  slow
E)  isotonicF) All of the above
G) None of the above

Question 12

In which muscle type do thick and thin filaments organize into sarcomeres?

Accepted Answer

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

Question 13

Which muscle type contracts by the sliding- filament mechanism?

Accepted Answer

A)  skeletal, smooth, and cardiac muscle
B)  smooth muscle only (single- unit or multi- unit) 
C)  skeletal and smooth muscle only
D)  skeletal muscle only
E)  smooth and cardiac muscle onlyF) None of the above
G) A) and C)

Question 14

What anchors thin filaments together?

Accepted Answer

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

Question 15

The interaction between actin and myosin in smooth muscle requires

Accepted Answer

A)  the tropomyosin must be moved out of the way by troponin before myosin can bind to actin.
B)  the interaction between calcium and troponin to expose the myosin binding site on the actin molecule.
C)  that the calcium- calmodulin complex directly phosphorylates myosin light chain, allowing myosin to bind to actin.
D)  that the calcium- calmodulin complex activates myosin light- chain kinase, which phosphorylates myosin thereby allowing it to bind with actin.
E)  the activation of troponin, which stimulates myosin light- chain kinase to phosphorylate myosin light chain, allowing myosin to bind with actin.F) A) and B)
G) A) and E)

Question 16

Intrafusal muscle fibers contribute directly to the tension produced during muscle contraction.

Accepted Answer

A) True 
 B)False

Question 17

What is the functional unit of skeletal muscle?

Accepted Answer

A)  tendons
B)  actin and myosin
C)  sarcomeres
D)  motor end plate
E)  sarcoplasmic reticulumF) C) and D)
G) A) and B)

Question 18

A skeletal muscle cell produces force for only a small portion of its contractile cycle because only a small portion of the crossbridge cycle involves force generation.

Accepted Answer

A) True 
 B)False

Question 19

The speed with which smooth muscle cells contract is similar to fast glycolytic skeletal muscle cells.

Accepted Answer

A) True 
 B)False

Question 20

Which of the following attaches muscle to bone?

Accepted Answer

A)  motor end plate
B)  actin and myosin
C)  tendons
D)  sarcoplasmic reticulum
E)  sarcomeresF) A) and B)
G) A) and E)

Exam 12: Muscle Physiology

Which of the following is the voltage sensor that initiates an increase in cytoplasmic calcium in response to an action potential?

Correct AnswerverifiedShow Answer

(Single- unit / Multi- unit)smooth muscle contains pacemaker cells.

Correct AnswerverifiedShow Answer

Which muscle type contracts by the sliding- filament mechanism?

Correct AnswerverifiedShow Answer

Intrafusal muscle fibers contribute directly to the tension produced during muscle contraction.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

The decreased ability of a muscle to maintain a constant force of contraction during repetitive stimulation is called what?

Correct AnswerverifiedShow Answer

The tension produced during skeletal muscle contraction can be increased by all of the following EXCEPT

Correct AnswerverifiedShow Answer

The interaction between actin and myosin in smooth muscle requires

Correct AnswerverifiedShow Answer

Oxidative phosphorylation is the primary energy source for cardiac muscle.

Correct AnswerverifiedShow Answer

The mechanism responsible for the size principle involves

Correct AnswerverifiedShow Answer

Which type of skeletal muscle fiber fatigues rapidly?

Correct AnswerverifiedShow Answer

The speed with which smooth muscle cells contract is similar to fast glycolytic skeletal muscle cells.

Correct AnswerverifiedShow Answer

Some muscle cells have pacemaker activity. These include

Correct AnswerverifiedShow Answer

Which of the following attaches muscle to bone?

Correct AnswerverifiedShow Answer

In which muscle type do thick and thin filaments organize into sarcomeres?

Correct AnswerverifiedShow Answer

What is the functional unit of skeletal muscle?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A skeletal muscle cell produces force for only a small portion of its contractile cycle because only a small portion of the crossbridge cycle involves force generation.

Correct AnswerverifiedShow Answer

What anchors thin filaments together?

Correct AnswerverifiedShow Answer

The two types of sensory endings found in muscle spindles are the annulospiral endings and

Correct AnswerverifiedShow Answer

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