Question 1

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 works 
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 works

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. 
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.

Question 3

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. 
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.

Question 4

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. 
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.

Question 5

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

Question 6

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

Question 7

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. 
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.

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

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

Question 10

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. 
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.

Question 11

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. 
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.

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

Which of the following is true concerning isotonic concentric contraction?

Which of the following is true?

Which of the following is true about skeletal muscle?

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

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

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

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

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

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

When an action potential reaches the presynaptic terminal,

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Exam 9: Muscular System: Histology and Physiology

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

Which of the following is true concerning isotonic concentric contraction?

Which of the following is true?

Which of the following is true about skeletal muscle?

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

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

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

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

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

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

When an action potential reaches the presynaptic terminal,

The Human Organism

The Chemical Basis of Life

Cell Biology

Tissues

Integumentary System

Skeletal System: Bones and Bone Tissue

Skeletal System: Gross Anatomy

Joint and Movement

Muscular System: Gross Anatomy

Functional Organization of Nervous Tissue

Spinal Cord and Spinal Nerves

Brain and Cranial Nerves

Integration of Nervous System Functions

The Special Senses

Autonomic Nervous System

Functional Organization of the Endocrine System

Endocrine Glands

Cardiovascular System: Blood

Cardiovascular System: the Heart

Cardiovascular System: Blood Vessels and Circulation

Lymphatic System and Immunity

Respiratory System

Digestive System

Nutrition, Metabolism, and Temperature Regulation

Urinary System

Water, Electrolyte, and Acid-Base Balance

Reproductive System

Development, Growth, Aging, and Genetics

Filters

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