Question 1

What would result from a lack of extracellular Ca2+ at the neuromuscular junction?

Accepted Answer

A)   Excessive synaptic vesicles would fuse and release too much ACh, overstimulating the myofiber.
B)   Synaptic vesicles would fail to fuse and ACh would not be released.
C)   Nothing would happen because extracellular Ca2+ does not play a role in muscle stimulation.
D)   The neuron must use its intracellular Ca2+ to make the vesicles fuse.
E)   Potassium ions are used in place of Ca2+ to ensure the vesicles fuse.F) C) and D)
G) A) and C)

Question 2

Which of the following is true concerning isotonic concentric contraction?

Accepted Answer

A)   The muscle shortens, but tension remains constant.
B)   The muscle lengthens, but tension remains constant.
C)   The muscle tenses and shortens.
D)   The muscle tenses, but length remains unchanged.
E)   The muscle lengthens, and tension declines.F) C) and D)
G) B) and D)

Question 3

A stimulus either causes an action potential or it doesn't. This is called

Accepted Answer

A)   an all-or-none response.
B)   a graded response.
C)   a latent period response.
D)   a relative refractory response.
E)   an arbitrary response.F) B) and E)
G) A) and E)

Question 4

Which of the following is true during the resting membrane potential?

Accepted Answer

A)   Sodium ion concentration is greater inside cells.
B)   Negatively charged proteins are more concentrated outside the cell.
C)   A greater concentration of calcium ions is found inside the cell.
D)   Potassium is concentrated primarily inside the cell.
E)   None of these choices reflect what occurs during the resting membrane potential.F) B) and D)
G) All of the above

Question 5

When an action potential reaches the presynaptic terminal,

Accepted Answer

A)   calcium ions diffuse into the presynaptic terminal through voltage-gated ion channels.
B)   acetylcholine moves into the presynaptic terminal.
C)   a local potential is generated in the presynaptic terminal.
D)   ligand-gated ion channels in the presynaptic terminal are opened.
E)   nothing else happens.F) A) and D)
G) C) and E)

Question 6

The model that describes the contraction of the muscle is called the

Accepted Answer

A)   contraction cycle.
B)   power stroke.
C)   sliding filament model.
D)   slipping fibril mechanism.
E)   paddle model.F) C) and D)
G) A) and B)

Question 7

Which of the following is true?

Accepted Answer

A)   Muscle fatigue has no influence on the force of contractions.
B)   A threshold stimulus will cause contraction of a muscle fiber.
C)   A subthreshold stimulus causes a muscle contraction.
D)   Motor units do not obey the "all or none" law.
E)   A threshold stimulus will not affect motor units.F) A) and B)
G) B) and C)

Question 8

The type of neurotransmitter or hormone that binds to receptors on smooth muscle plasma membranes determines the response of the muscle.

Accepted Answer

A) True 
 B)False

Question 9

Which of the following is true about skeletal muscle?

Accepted Answer

A)   Sensory neurons stimulate muscles to contract.
B)   There are very few blood vessels in skeletal muscle.
C)   Every muscle fiber receives a branch of an axon from the nerve.
D)   There are very few nerve fibers in a muscle.
E)   All of the choices are true.F) C) and E)
G) B) and C)

Question 10

The condition of painful, spasmodic contractions of muscles is referred to as

Accepted Answer

A)   cramps.
B)   fibrositis.
C)   fibromyalgia.
D)   muscular dystrophy.
E)   paralysis.F) A) and C)
G) D) and E)

Question 11

Which of the following changes have the potential to dramatically affect the potential difference across the plasma membrane?

Accepted Answer

A)   Increased permeability of the membrane to Na+
B)   Increased intracellular concentration of K+
C)   Any change in the rate at which the sodium-potassium pump works
D)   Increased permeability of the membrane to Na+ and increased intracellular concentration of K+
E)   Increased permeability of the membrane to Na+, increased intracellular concentration of K+, and any change in the rate at which the sodium-potassium pump worksF) A) and E)
G) C) and E)

Exam 9: Muscular System: Histology and Physiology

What would result from a lack of extracellular Ca²⁺ at the neuromuscular junction?

Correct Answer
verified

When an action potential reaches the presynaptic terminal,

Correct Answer
verified

Which of the following is true concerning isotonic concentric contraction?

Correct Answer
verified

Which of the following changes have the potential to dramatically affect the potential difference across the plasma membrane?

Correct Answer
verified

Which of the following is true about skeletal muscle?

Correct Answer
verified

The type of neurotransmitter or hormone that binds to receptors on smooth muscle plasma membranes determines the response of the muscle.

Correct Answer
verified

The model that describes the contraction of the muscle is called the

Correct Answer
verified

The condition of painful, spasmodic contractions of muscles is referred to as

Correct Answer
verified

Which of the following is true?

Correct Answer
verified

Which of the following is true during the resting membrane potential?

Correct Answer
verified

A stimulus either causes an action potential or it doesn't. This is called

Correct Answer
verified

Exam 9: Muscular System: Histology and Physiology

What would result from a lack of extracellular Ca2+ at the neuromuscular junction?

Correct AnswerverifiedShow Answer

When an action potential reaches the presynaptic terminal,

Correct AnswerverifiedShow Answer

Which of the following is true concerning isotonic concentric contraction?

Correct AnswerverifiedShow Answer

Which of the following changes have the potential to dramatically affect the potential difference across the plasma membrane?

Correct AnswerverifiedShow Answer

Which of the following is true about skeletal muscle?

Correct AnswerverifiedShow Answer

The type of neurotransmitter or hormone that binds to receptors on smooth muscle plasma membranes determines the response of the muscle.

Correct AnswerverifiedShow Answer

The model that describes the contraction of the muscle is called the

Correct AnswerverifiedShow Answer

The condition of painful, spasmodic contractions of muscles is referred to as

Correct AnswerverifiedShow Answer

Which of the following is true?

Correct AnswerverifiedShow Answer

Which of the following is true during the resting membrane potential?

Correct AnswerverifiedShow Answer

A stimulus either causes an action potential or it doesn't. This is called

Correct AnswerverifiedShow Answer

What would result from a lack of extracellular Ca²⁺ at the neuromuscular junction?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
verified

Correct Answer
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