Question 1

The electrical properties of cells are the result of

Accepted Answer

A)   ion concentration differences across the plasma membrane.
B)   receptor sites that are present on the plasma membrane.
C)   phosphorylation reactions within the cytoplasm.
D)   phospholipids in the plasma membrane.
E)   None of these choices are correct.F) C) and D)
G) D) and E)

Question 2

Consider a chemical that blocks the action of acetylcholinesterase. What effect does this have on muscles?

Accepted Answer

A)   It would cause paralysis.
B)   It would cause action potentials to be inhibited, thereby rendering the muscle useless.
C)   The body would increase its production of acetylcholine to compensate.
D)   The axons of the motor neurons would atrophy, and the muscle would weaken.
E)   The muscle would have no way to relax, and spastic contractions would result.F) D) and E)
G) A) and E)

Question 3

Which of the following is not an important function of calcium ions in skeletal muscle activity?

Accepted Answer

A)   Depolarization of the sarcolemma
B)   Release of acetylcholine from the presynaptic terminal
C)   Exposure of the active sites on G actin
D)   All of these are important functions of calcium ions in skeletal muscle contraction.E) None of the above
F) A) and C)

Question 4

During the contraction phase of a muscle twitch,

Accepted Answer

A)   acetylcholine stimulates the pre-synaptic terminal.
B)   Na+ diffuse into the muscle fiber.
C)   actin-myosin cross-bridges form.
D)   Ca2+ are transported back to the sarcoplasmic reticulum.
E)   the action potential travels down the T tubule.F) None of the above
G) A) and D)

Question 5

Michael Jordan was arguably the best player in professional basketball history. Scientifically, one would expect him to have highly developed ________ fibers.

Accepted Answer

A)   red
B)   white
C)   intermediate
D)   fast twitch
E)   slow oxidativeF) A) and D)
G) D) and E)

Question 6

Anabolic steroids can do all of the following except

Accepted Answer

A)   increase muscle size and strength.
B)   cause testicular atrophy.
C)   cause cardiovascular disease.
D)   increase the number of muscle fibers.
E)   increase total muscle mass.F) A) and E)
G) A) and D)

Question 7

In which of the following situations does a resting membrane potential exist?

Accepted Answer

A)   A relaxed muscle fiber
B)   A conducting neuron
C)   A stimulated sensory receptor in the skin
D)   A contracting cardiac muscle cell
E)   The eye seeing an imageF) D) and E)
G) A) and B)

Question 8

Which of the following causes an unequal ion concentration across the resting plasma membrane?

Accepted Answer

A)   The functioning of the sodium-chloride pump
B)   Negatively charged proteins not readily diffusing across the plasma membrane
C)   The attraction of chloride ions to other intracellular anions
D)   The repulsion of potassium ions by the intracellular anions
E)   The attraction of sodium ions to chloride ionsF) A) and D)
G) A) and B)

Question 9

Whales are air-breathing aquatic mammals, and some species can remain underwater for long periods of time. Which type of skeletal muscle fibers are most likely dominant in these deep diving whales?

Accepted Answer

A)   Slow fibers
B)   Fast (type IIa)  fibers
C)   Fast (IIb)  fibers
D)   White fibersE) A) and D)
F) A) and C)

Question 10

-The figure illustrates a detailed drawing of the neuromuscular junction. What does "D" represent?

Accepted Answer

A)   Synaptic vesicles
B)   Synaptic cleft
C)   Sarcolemma
D)   Presynaptic terminal
E)   Postsynaptic membraneF) A) and E)
G) B) and E)

Question 11

Whole muscles can respond in a graded fashion to stimuli by varying

Accepted Answer

A)   the force of contraction of individual muscle fibers.
B)   the number of motor units recruited.
C)   the amplitude of the action potential.
D)   the frequency of stimulus.
E)   thresholds.F) A) and C)
G) A) and D)

Question 12

An antibody test on smooth muscle reveals fewer dense bodies and intermediate filaments in a patient with a colon disorder. What is the purpose of these structures?

Accepted Answer

A)   They allow for rapidly developing action potentials in smooth muscle cells.
B)   They are shallow invaginations of plasma membrane.
C)   They maintain relatively constant tension in smooth muscle for a period of time.
D)   They are part of the intracellular cytoskeleton.
E)   They act as enzymes that remove phosphate from myosin.F) A) and B)
G) D) and E)

Question 13

Which type of muscle tissue causes vasoconstriction?

Accepted Answer

A)   Skeletal muscle
B)   Smooth muscle
C)   Cardiac muscleD) B) and C)
E) All of the above

Question 14

Which of the following statements does not accurately describe factors that determine the amount of force generated during a muscle contraction?

Accepted Answer

A)   The number of cross-bridges that can form is higher in a short muscle fiber compared to longer fibers.
B)   Muscle fibers that have larger diameters have more myofibrils and therefore can form more cross-bridges.
C)   Increasing stimulation of a muscle fiber results in increased formation of cross-bridges.
D)   Muscle fibers that are stretched to the optimal length will provide higher numbers of cross-bridges.E) C) and D)
F) A) and B)

Question 15

Muscles exhibit the property of excitability. This means that the muscle

Accepted Answer

A)   shortens its length.
B)   recoils to its original resting length.
C)   stretches beyond its normal length.
D)   responds to stimulation by the nervous system.
E)   excites itself.F) A) and B)
G) B) and C)

Question 16

Which fibers are primarily responsible for producing lactate?

Accepted Answer

A)   Slow fibers
B)   Type IIA fast fibers
C)   Type IIB fast fibers
D)   Type I slow-twitch fibers
E)   Red fibersF) B) and C)
G) B) and D)

Question 17

A toxin released by the anaerobic bacterium Clostridium botulinum causes the food-borne illness known as botulism, which inhibits the release of ACh at the neuromuscular junction. What effect does this have on a person infected with the bacterium?

Accepted Answer

A)   It causes flaccid paralysis, and if it affects the respiratory muscles, can result in death.
B)   It disrupts the balance between ACh and acetylcholinesterase, leading to spastic contractions.
C)   The brain compensates by producing more ACh, limiting the illness to only a few hours.
D)   The jaws are most affected, and it results in "lockjaw."
E)   Problems only result when the individual has low immunity.F) A) and D)
G) C) and D)

Question 18

Randy is participating in a strong man competition and is required to pull a yacht as far as he can. Which type of chemical process will his skeletal muscles rely on during this competition?

Accepted Answer

A)   Anaerobic respiration
B)   Aerobic respiration
C)   Both anaerobic respiration and aerobic respiration are correct.D) A) and B)
E) A) and C)

Question 19

Inflammation of the fibrous connective tissue resulting in stiffness and soreness is

Accepted Answer

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

Question 20

The H zone

Accepted Answer

A)   contains only myosin myofilaments.
B)   contains only actin myofilaments.
C)   contains both myosin and actin myofilaments.D) None of the above
E) All of the above

Exam 9: Muscular System: Histology and Physiology

Which of the following statements does not accurately describe factors that determine the amount of force generated during a muscle contraction?

Correct AnswerverifiedShow Answer

A toxin released by the anaerobic bacterium Clostridium botulinum causes the food-borne illness known as botulism, which inhibits the release of ACh at the neuromuscular junction. What effect does this have on a person infected with the bacterium?

Correct AnswerverifiedShow Answer

Whales are air-breathing aquatic mammals, and some species can remain underwater for long periods of time. Which type of skeletal muscle fibers are most likely dominant in these deep diving whales?

Correct AnswerverifiedShow Answer

-The figure illustrates a detailed drawing of the neuromuscular junction. What does "D" represent?

Correct AnswerverifiedShow Answer

Anabolic steroids can do all of the following except

Correct AnswerverifiedShow Answer

In which of the following situations does a resting membrane potential exist?

Correct AnswerverifiedShow Answer

Which type of muscle tissue causes vasoconstriction?

Correct AnswerverifiedShow Answer

Which of the following causes an unequal ion concentration across the resting plasma membrane?

Correct AnswerverifiedShow Answer

Muscles exhibit the property of excitability. This means that the muscle

Correct AnswerverifiedShow Answer

During the contraction phase of a muscle twitch,

Correct AnswerverifiedShow Answer

Which fibers are primarily responsible for producing lactate?

Correct AnswerverifiedShow Answer

The electrical properties of cells are the result of

Correct AnswerverifiedShow Answer

The H zone

Correct AnswerverifiedShow Answer

An antibody test on smooth muscle reveals fewer dense bodies and intermediate filaments in a patient with a colon disorder. What is the purpose of these structures?

Correct AnswerverifiedShow Answer

Michael Jordan was arguably the best player in professional basketball history. Scientifically, one would expect him to have highly developed ________ fibers.

Correct AnswerverifiedShow Answer

Randy is participating in a strong man competition and is required to pull a yacht as far as he can. Which type of chemical process will his skeletal muscles rely on during this competition?

Correct AnswerverifiedShow Answer

Which of the following is not an important function of calcium ions in skeletal muscle activity?

Correct AnswerverifiedShow Answer

Whole muscles can respond in a graded fashion to stimuli by varying

Correct AnswerverifiedShow Answer

Inflammation of the fibrous connective tissue resulting in stiffness and soreness is

Correct AnswerverifiedShow Answer

Consider a chemical that blocks the action of acetylcholinesterase. What effect does this have on muscles?

Correct AnswerverifiedShow Answer

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