Question 1

Drugs called calcium channel blockers may be used to lower blood pressure by causing arteries to vasodilate. How do you suppose these drugs work?

Accepted Answer

A)   They prevent calcium from entering the sarcoplasmic reticulum of smooth muscle.
B)   They stimulate the calcium pump in smooth muscle, thus removing calcium from the calmodulin.
C)   They prevent calcium from exiting the sarcoplasmic reticulum in skeletal muscle.
D)   They prevent calcium from entering cardiac muscle, thus slowing down the heart rate.
E)   They prevent calcium from entering smooth muscle, thus allowing the muscle to relax.F) A) and B)
G) All of the above

Question 2

An eccentric contraction is described as

Accepted Answer

A)   action potential frequency is high enough that no relaxation of muscle fibers occurs.
B)   a muscle produces constant tension during contraction.
C)   a muscle produces an increasing tension during contraction.
D)   a muscle produces increasing tension as it shortens.
E)   a muscle produces tension, but the length of the muscle is increasing.F) A) and C)
G) B) and E)

Question 3

The sites where a chemical substance is transmitted from the presynaptic terminal of an axon to the postsynaptic membrane of a muscle fiber are called

Accepted Answer

A)   neuromuscular junctions.
B)   sarcomeres.
C)   myofilaments.
D)   Z disks.
E)   cell bodies of neurons.F) B) and C)
G) A) and E)

Question 4

Complete tetanus

Accepted Answer

A)   is the time during which the tissue cannot respond again.
B)   results in complete and incomplete tetanus.
C)   is the condition in which the muscle fiber only partially relaxes between contractions.
D)   is the condition in which stimuli occur so rapidly that there are no intervening relaxations.
E)   is the constant tension produced by muscles for long periods of time.F) A) and B)
G) A) and C)

Question 5

Muscle myofibrils

Accepted Answer

A)   are found in the sarcolemma.
B)   extend from the sarcolemma to the T-tubule.
C)   contain myosin and actin myofilaments.
D)   hold muscle fibers together.
E)   do not appear striated.F) A) and E)
G) A) and C)

Question 6

Which of the following is mismatched?

Accepted Answer

A)   I band - contains only actin
B)   M line - middle of the H zone
C)   Z disk - structure between adjacent sarcomeres
D)   Myosin myofilaments - thin myofilaments
E)   Actin myofilaments - thin myofilamentsF) B) and C)
G) A) and B)

Question 7

A drug that interferes with the active transport of Ca2+ from the sarcoplasm back into the sarcoplasmic reticulum would result in

Accepted Answer

A)   relaxation of the muscle fiber.
B)   contraction with no relaxation.
C)   muscle hypertrophy.
D)   fibrosis of the muscle.
E)   an imbalance of blood calcium.F) A) and E)
G) None of the above

Question 8

Synaptic vesicles in the neuromuscular junction contain

Accepted Answer

A)   calcium.
B)   ATP.
C)   acetylcholine.
D)   acetylcholinesterase.
E)   sodium.F) B) and C)
G) A) and D)

Question 9

Which type of muscle tissue causes peristalsis?

Accepted Answer

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

Question 10

If one nerve stimulus arrives at a muscle fiber so soon that the fiber does NOT relax at all from the previous twitch, the most likely result will be ________.

Accepted Answer

A)   fatigue
B)   spasm
C)   incomplete tetanus
D)   complete tetanus
E)   wave summationF) A) and B)
G) D) and E)

Question 11

Which muscle(s)  can contract without the need for nervous stimulation?

Accepted Answer

A)   Skeletal muscle only
B)   Smooth muscle only
C)   Cardiac muscle only
D)   Smooth and cardiac muscle
E)   Skeletal, smooth, and cardiac muscleF) All of the above
G) A) and B)

Question 12

Athletes who train at high altitudes increase their red blood cell count, which increases their oxygen supply during exercise. Increased oxygen supply results in

Accepted Answer

A)   increased glycolysis.
B)   increased use of myokinase.
C)   longer aerobic respiration.
D)   longer anaerobic respiration.
E)   reduced ATP consumption.F) C) and E)
G) B) and D)

Question 13

The plasma membrane of an excitable cell is more permeable to K+ because

Accepted Answer

A)   of its positive electrical charge.
B)   there are more leak ion channels for K+ than Na+.
C)   protein molecules cannot exit through the plasma membrane.
D)   calcium ions block Na+ and Cl- channels.
E)   there are more gated channels for K+.F) B) and D)
G) C) and D)

Question 14

Which of the following are reasons that shivering raises body temperature? (Check all that apply.)

Accepted Answer

A)   Shivering decreases warm blood flow to the core while increasing flow to the muscles.
B)   Shivering depresses metabolism.
C)   Shivering increases heat production up to 18 times that of resting levels.
D)   The process of muscle contraction produces heat.E) A) and D)
F) B) and C)

Question 15

Epimysium

Accepted Answer

A)   surrounds individual muscles.
B)   separates muscle fibers.
C)   connects muscles to bone.
D)   is a type of muscle tissue.
E)   is a type of nerve tissue.F) A) and E)
G) B) and E)

Question 16

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

Accepted Answer

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

Question 17

Which type of muscle tissue would cause flexion and extension of the arm?

Accepted Answer

A)   Skeletal muscle
B)   Smooth muscle
C)   Cardiac muscleD) A) and B)
E) A) and C)

Question 18

Which of the following helps explain the increased tension seen in multiple wave summation?

Accepted Answer

A)   Increased motor unit recruitment
B)   Increased concentration of Ca2+ around the myofibrils
C)   Exposure of more active sites on myosin myofilaments
D)   The breakdown of elastic elements in the cell
E)   Decreased stimulus frequencyF) A) and C)
G) B) and E)

Question 19

Oxygen deficit represents

Accepted Answer

A)   the amount anaerobic metabolism must increase after exercise.
B)   the amount of O2 converted to lactate during exercise.
C)   the amount of CO2 that cells need to eliminate.
D)   conversion of pyruvate to lactate.
E)   the amount of O2 that cells need to replenish ATP supplies after exercise.F) B) and D)
G) None of the above

Question 20

After contraction has occurred, the Ca2+ are

Accepted Answer

A)   destroyed by cholinesterase.
B)   chemically bound to the cross bridges.
C)   secreted by the Golgi apparatus to the outside of the cell.
D)   released from troponin.
E)   returned to the sarcolemma.F) All of the above
G) D) and E)

Exam 9: Muscular System: Histology and Physiology

A drug that interferes with the active transport of Ca2+ from the sarcoplasm back into the sarcoplasmic reticulum would result in

Correct AnswerverifiedShow Answer

The plasma membrane of an excitable cell is more permeable to K+ because

Correct AnswerverifiedShow Answer

Oxygen deficit represents

Correct AnswerverifiedShow Answer

Which of the following helps explain the increased tension seen in multiple wave summation?

Correct AnswerverifiedShow Answer

Which of the following is mismatched?

Correct AnswerverifiedShow Answer

Which of the following are reasons that shivering raises body temperature? (Check all that apply.)

Correct AnswerverifiedShow Answer

Drugs called calcium channel blockers may be used to lower blood pressure by causing arteries to vasodilate. How do you suppose these drugs work?

Correct AnswerverifiedShow Answer

Which muscle(s) can contract without the need for nervous stimulation?

Correct AnswerverifiedShow Answer

Which type of muscle tissue would cause flexion and extension of the arm?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

The sites where a chemical substance is transmitted from the presynaptic terminal of an axon to the postsynaptic membrane of a muscle fiber are called

Correct AnswerverifiedShow Answer

If one nerve stimulus arrives at a muscle fiber so soon that the fiber does NOT relax at all from the previous twitch, the most likely result will be ________.

Correct AnswerverifiedShow Answer

Which type of muscle tissue causes peristalsis?

Correct AnswerverifiedShow Answer

An eccentric contraction is described as

Correct AnswerverifiedShow Answer

Muscle myofibrils

Correct AnswerverifiedShow Answer

Synaptic vesicles in the neuromuscular junction contain

Correct AnswerverifiedShow Answer

Athletes who train at high altitudes increase their red blood cell count, which increases their oxygen supply during exercise. Increased oxygen supply results in

Correct AnswerverifiedShow Answer

Epimysium

Correct AnswerverifiedShow Answer

Complete tetanus

Correct AnswerverifiedShow Answer

After contraction has occurred, the Ca2+ are

Correct AnswerverifiedShow Answer

A drug that interferes with the active transport of Ca²⁺ from the sarcoplasm back into the sarcoplasmic reticulum would result in

Correct Answer
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The plasma membrane of an excitable cell is more permeable to K⁺ because

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After contraction has occurred, the Ca²⁺ are

Correct Answer
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