Question 1

Which of the following choices lists a correct sequence of events following the depolarization of transverse tubules in excitation-contraction coupling in cardiac muscle?

Accepted Answer

A)  Calcium release into cytosol,calcium ion influx through sarcolemma,actin and myosin attach,thin filaments slide toward the middle of sarcomeres
B)  Actin and myosin attach,thin filaments slide toward the middle of sarcomeres,calcium release into cytosol
C)  Calcium release into cytosol,actin and myosin attach,calcium ion influx through sarcolemma,thin myofilaments slide toward the middle of sarcomeres
D)  Calcium release into cytosol,actin and myosin attach,thin filaments slide toward the middle of sarcomeres,calcium ion influx through sarcolemma
E)  Calcium ion influx through sarcolemma,calcium release into cytosol,actin and myosin attach,thin myofilaments slide toward the middle of sarcomeresF) A) and C)
G) None of the above

Question 2

The difference in color between white muscle and red muscle is accounted for by the greater abundance of glycogen in white muscle.

Accepted Answer

A) True 
 B)False  False

Question 3

If a muscle cell expressed muscarinic ACh channels,which are only permeable to Na⁺ instead of nicotinic ACh channels,which are permeable to both Na⁺ and K⁺,which portion of a muscle cell would be inhibited?

Accepted Answer

A)  Neurotransmitter release from the motor neuron
B)  Muscle cell depolarization
C)  Cross-bridge cycling
D)  Relaxation
E)  None of the answer choices are correctF) All of the above
G) A) and D)

Question 4

The shortening velocity of a skeletal muscle fiber increases with decreasing load because the rate at which the cross-bridge cycle can occur increases with decreasing load.

Accepted Answer

A) True 
 B)False

Question 5

Which of the following does NOT correctly describe cardiac muscle cells?

Accepted Answer

A)  They are arranged in layers surrounding hollow cavities in the heart.
B)  They are much shorter than skeletal muscle fibers,and generally have a single nucleus.
C)  Their membranes are depolarized initially by the influx of sodium ions.
D)  They depolarize prior to contraction.
E)  They can contract in the absence of external calcium.F) A) and D)
G) A) and C)

Question 6

Unlike humans,cows eat all day.They spend hours and hours chewing with very little rest from the task in a 24-hour period.The food they eat (grass) is difficult to break down,requiring a lot of chewing.Understanding the endurance required for these chewing muscles,what fiber type would you expect to be predominant in their chewing muscles?

Accepted Answer

A)  Type 1
B)  Type 2A
C)  Type 2X
D)  Type 3
E)  There is not enough information to predict a dominant muscle fiber typeF) None of the above
G) A) and D)

Question 7

Type 2X skeletal muscle fibers have fast myosin ATPase activity.

Accepted Answer

A) True 
 B)False

Question 8

Myasthenia gravis is an autoimmune disease in which the immune system gradually destroys the receptors for acetylcholine at the neuromuscular junction.Which of the following drugs might initially be useful in treating the symptoms of this disease?

Accepted Answer

A)  A drug that inhibits acetylcholinesterase
B)  A drug that inhibits release of acetylcholine
C)  Curare
D)  Atropine (a muscarinic acetylcholine receptor antagonist) 
E)  A nicotinic acetylcholine receptor antagonistF) A) and B)
G) D) and E)

Question 9

The name given to the repeating functional units that cause striations in a skeletal muscle myofibril is "sarcomere."

Accepted Answer

A) True 
 B)False

Question 10

As a muscle gets stronger the diameter of its individual muscle cells becomes larger.Which of the following structures ensures that the membrane potential change is translated into the depth of the cell?

Accepted Answer

A)  Z lines
B)  Sarcoplasmic reticulum
C)  H zone
D)  Transverse tubules
E)  Pores in the plasma membraneF) A) and B)
G) D) and E)

Question 11

Which dietary supplement is most likely to contribute to greater skeletal muscle ATP availability in the first few seconds of skeletal muscle contraction?

Accepted Answer

A)  Fatty acids
B)  Sports drinks with electrolytes
C)  Sugar
D)  Protein
E)  CreatineF) C) and E)
G) A) and E)

Question 12

Neuronal stimulation of skeletal muscle is always excitatory,whereas neuronal stimulation of smooth muscle may be excitatory or inhibitory.

Accepted Answer

A) True 
 B)False  True

Question 13

Being able to generate more force with a muscle could include variations in motor unit recruitment or muscle cell hypertrophy.

Accepted Answer

A) True 
 B)False

Question 14

More myoglobin is typically found in type 2X skeletal muscle fibers.

Accepted Answer

A) True 
 B)False

Question 15

Which of these would increase the tension generated in a skeletal muscle?

Accepted Answer

A)  Increasing the frequency of firing in alpha motor neurons innervating the muscle
B)  Stretching the muscle to very long lengths
C)  Resting the muscle for several weeks
D)  Switching off fast-glycolytic motor units and activating an equal number of slow-oxidative motor units
E)  Increasing the amplitude of action potentials in the alpha motor neurons that innervate the muscleF) A) and E)
G) B) and D)

Question 16

With athletic conditioning,type 2 muscle fibers can gain myoglobin.

Accepted Answer

A) True 
 B)False

Question 17

Curare blocks neuromuscular transmission by preventing the release of neurotransmitters from the motor neuron.

Accepted Answer

A) True 
 B)False

Question 18

The larger the diameter of a skeletal muscle fiber,the greater the tension it can generate.

Accepted Answer

A) True 
 B)False

Question 19

A scientist labels ACh with fluorescent dye to be able to visualize under the microscope where ACh travels and binds.She takes an image of the motor end plate and see that ACh is

Accepted Answer

A)  bound to muscarinic receptors at the end plate.
B)  inside the muscle cell sarcoplasm.
C)  bound to acetylcholinesterase in the end plate membrane.
D)  bound to receptors on the sarcoplasmic reticulum.
E)  bound to Ca²⁺ ions.F) None of the above
G) A) and E)

Question 20

Sarah is a sprinter who specializes in quick and powerful bursts of speed followed by periods of rest.Priya is a marathon runner who specializes in long,steady runs.Compared to Sarah's muscles,how are Priya's most likely to differ?

Accepted Answer

A)  Priya muscles will have more glycogen stored in her type 2X muscle fibers.
B)  Priya's muscles will have more mitochondria in her type 1 and 2A muscle fibers.
C)  Priya's muscles will have less myoglobin in her type 1 muscle fibers.
D)  Priya's type 2X fibers will be larger in diameter.
E)  Priya will have a greater proportion of type 2 muscle fibers and a lower proportion of type 1 fibers than Sarah.F) A) and C)
G) B) and E) B

Exam 9: Muscle

Which of the following choices lists a correct sequence of events following the depolarization of transverse tubules in excitation-contraction coupling in cardiac muscle?

Correct Answer
verified

The difference in color between white muscle and red muscle is accounted for by the greater abundance of glycogen in white muscle.

Correct Answer
verified
False

If a muscle cell expressed muscarinic ACh channels,which are only permeable to Na⁺ instead of nicotinic ACh channels,which are permeable to both Na⁺ and K⁺,which portion of a muscle cell would be inhibited?

Correct Answer
verified

The shortening velocity of a skeletal muscle fiber increases with decreasing load because the rate at which the cross-bridge cycle can occur increases with decreasing load.

Correct Answer
verified

Which of the following does NOT correctly describe cardiac muscle cells?

Correct Answer
verified

Correct Answer
verified

Type 2X skeletal muscle fibers have fast myosin ATPase activity.

Correct Answer
verified

Myasthenia gravis is an autoimmune disease in which the immune system gradually destroys the receptors for acetylcholine at the neuromuscular junction.Which of the following drugs might initially be useful in treating the symptoms of this disease?

Correct Answer
verified

The name given to the repeating functional units that cause striations in a skeletal muscle myofibril is "sarcomere."

Correct Answer
verified

As a muscle gets stronger the diameter of its individual muscle cells becomes larger.Which of the following structures ensures that the membrane potential change is translated into the depth of the cell?

Correct Answer
verified

Which dietary supplement is most likely to contribute to greater skeletal muscle ATP availability in the first few seconds of skeletal muscle contraction?

Correct Answer
verified

Neuronal stimulation of skeletal muscle is always excitatory,whereas neuronal stimulation of smooth muscle may be excitatory or inhibitory.

Correct Answer
verified
True

Being able to generate more force with a muscle could include variations in motor unit recruitment or muscle cell hypertrophy.

Correct Answer
verified

More myoglobin is typically found in type 2X skeletal muscle fibers.

Correct Answer
verified

Which of these would increase the tension generated in a skeletal muscle?

Correct Answer
verified

With athletic conditioning,type 2 muscle fibers can gain myoglobin.

Correct Answer
verified

Curare blocks neuromuscular transmission by preventing the release of neurotransmitters from the motor neuron.

Correct Answer
verified

The larger the diameter of a skeletal muscle fiber,the greater the tension it can generate.

Correct Answer
verified

A scientist labels ACh with fluorescent dye to be able to visualize under the microscope where ACh travels and binds.She takes an image of the motor end plate and see that ACh is

Correct Answer
verified

Sarah is a sprinter who specializes in quick and powerful bursts of speed followed by periods of rest.Priya is a marathon runner who specializes in long,steady runs.Compared to Sarah's muscles,how are Priya's most likely to differ?

Correct Answer
verified
B

Exam 9: Muscle

Which of the following choices lists a correct sequence of events following the depolarization of transverse tubules in excitation-contraction coupling in cardiac muscle?

Correct AnswerverifiedShow Answer

The difference in color between white muscle and red muscle is accounted for by the greater abundance of glycogen in white muscle.

Correct AnswerverifiedFalse

If a muscle cell expressed muscarinic ACh channels,which are only permeable to Na⁺ instead of nicotinic ACh channels,which are permeable to both Na⁺ and K⁺,which portion of a muscle cell would be inhibited?

Correct AnswerverifiedShow Answer

The shortening velocity of a skeletal muscle fiber increases with decreasing load because the rate at which the cross-bridge cycle can occur increases with decreasing load.

Correct AnswerverifiedShow Answer

Which of the following does NOT correctly describe cardiac muscle cells?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Type 2X skeletal muscle fibers have fast myosin ATPase activity.

Correct AnswerverifiedShow Answer

Myasthenia gravis is an autoimmune disease in which the immune system gradually destroys the receptors for acetylcholine at the neuromuscular junction.Which of the following drugs might initially be useful in treating the symptoms of this disease?

Correct AnswerverifiedShow Answer

The name given to the repeating functional units that cause striations in a skeletal muscle myofibril is "sarcomere."

Correct AnswerverifiedShow Answer

As a muscle gets stronger the diameter of its individual muscle cells becomes larger.Which of the following structures ensures that the membrane potential change is translated into the depth of the cell?

Correct AnswerverifiedShow Answer

Which dietary supplement is most likely to contribute to greater skeletal muscle ATP availability in the first few seconds of skeletal muscle contraction?

Correct AnswerverifiedShow Answer

Neuronal stimulation of skeletal muscle is always excitatory,whereas neuronal stimulation of smooth muscle may be excitatory or inhibitory.

Correct AnswerverifiedTrue

Being able to generate more force with a muscle could include variations in motor unit recruitment or muscle cell hypertrophy.

Correct AnswerverifiedShow Answer

More myoglobin is typically found in type 2X skeletal muscle fibers.

Correct AnswerverifiedShow Answer

Which of these would increase the tension generated in a skeletal muscle?

Correct AnswerverifiedShow Answer

With athletic conditioning,type 2 muscle fibers can gain myoglobin.

Correct AnswerverifiedShow Answer

Curare blocks neuromuscular transmission by preventing the release of neurotransmitters from the motor neuron.

Correct AnswerverifiedShow Answer

The larger the diameter of a skeletal muscle fiber,the greater the tension it can generate.

Correct AnswerverifiedShow Answer

A scientist labels ACh with fluorescent dye to be able to visualize under the microscope where ACh travels and binds.She takes an image of the motor end plate and see that ACh is

Correct AnswerverifiedShow Answer

Sarah is a sprinter who specializes in quick and powerful bursts of speed followed by periods of rest.Priya is a marathon runner who specializes in long,steady runs.Compared to Sarah's muscles,how are Priya's most likely to differ?

Correct AnswerverifiedB

Correct Answer
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False

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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
verified
True

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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B