Question 1

Skeletal muscle develops from cells called

Accepted Answer

A)  fascicles. 
B)  myoblasts. 
C)  myofibrils. 
D)  myotomes. 
E)  fasciculi. 
A)  fascicles. 
B)  myoblasts. 
C)  myofibrils. 
D)  myotomes. 
E)  fasciculi. B

Question 2

A myofibril is the

Accepted Answer

A)  plasma membrane of a muscle fiber. 
B)  cytoplasm of a muscle fiber. 
C)  structural and functional unit of the skeletal muscle fiber. 
D)  contractile thread that extends the length of the muscle fiber. 
E)  protein strand composed of actin. 
A)  plasma membrane of a muscle fiber. 
B)  cytoplasm of a muscle fiber. 
C)  structural and functional unit of the skeletal muscle fiber. 
D)  contractile thread that extends the length of the muscle fiber. 
E)  protein strand composed of actin. D

Question 3

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

Accepted Answer

A)  Synaptic vesicles 
B)  Synaptic cleft 
C)  Sarcolemma 
D)  Presynaptic terminal 
E)  Postsynaptic membrane 
A)  Synaptic vesicles 
B)  Synaptic cleft 
C)  Sarcolemma 
D)  Presynaptic terminal 
E)  Postsynaptic membrane D

Question 4

-What does "D" represent on the diagram?

Accepted Answer

A)  Threshold 
B)  Depolarization 
C)  Depolarization phase of action potential 
D)  Repolarization phase of action potential 
A)  Threshold 
B)  Depolarization 
C)  Depolarization phase of action potential 
D)  Repolarization phase of action potential

Question 5

In excitation-contraction coupling,

Accepted Answer

A)  Ca2+ must bind with myosin to expose active sites on actin. 
B)  myosin heads bind to exposed active sites on actin. 
C)  cross-bridges form between myosin heads and Ca2+. 
D)  movement of the troponin-tropomyosin complex causes actin myofilaments to slide. 
E)  ATP binds to actin myofilaments. 
A)  Ca2+ must bind with myosin to expose active sites on actin. 
B)  myosin heads bind to exposed active sites on actin. 
C)  cross-bridges form between myosin heads and Ca2+. 
D)  movement of the troponin-tropomyosin complex causes actin myofilaments to slide. 
E)  ATP binds to actin myofilaments.

Question 6

The elevated oxygen consumption relative to activity level after exercise has ended is called

Accepted Answer

A)  oxygen deficit. 
B)  oxygen debt. 
C)  oxygen repayment. 
D)  excess post-exercise oxygen consumption. 
E)  anaerobic recovery. 
A)  oxygen deficit. 
B)  oxygen debt. 
C)  oxygen repayment. 
D)  excess post-exercise oxygen consumption. 
E)  anaerobic recovery.

Question 7

Arrange the following list of biochemical events in the correct sequence.
(1) An action potential is conducted deep into the muscle fiber by the T tubule.
(2) Calcium ions bind to troponin.
(3) The membranes of the sarcoplasmic reticulum become more permeable to calcium ions.
(4) Calcium ions diffuse into the sarcoplasm around the myofibril.
(5) The troponin-tropomyosin complex moves exposing active sites.

Accepted Answer

A)  1, 5, 2, 3, 4 
B)  1, 3, 4, 2, 5 
C)  1, 2, 3, 4, 5 
D)  1, 3, 2, 5, 4 
E)  1, 4, 3, 2, 5 
A)  1, 5, 2, 3, 4 
B)  1, 3, 4, 2, 5 
C)  1, 2, 3, 4, 5 
D)  1, 3, 2, 5, 4 
E)  1, 4, 3, 2, 5

Question 8

Curare blocks acetylcholine receptors at the motor end plate. This would result in

Accepted Answer

A)  increased stimulation of the muscle. 
B)  more acetylcholinesterase production. 
C)  lack of Ca2+ uptake by the muscle fiber. 
D)  inability of the muscle fiber to respond to nervous stimulation. 
E)  sustained contraction of the muscle. 
A)  increased stimulation of the muscle. 
B)  more acetylcholinesterase production. 
C)  lack of Ca2+ uptake by the muscle fiber. 
D)  inability of the muscle fiber to respond to nervous stimulation. 
E)  sustained contraction of the muscle.

Question 9

Which of the following statements best predicts the effect of a substance that blocks creatine kinase activity?

Accepted Answer

A)  ATP production from creatine phosphate would decrease. 
B)  ATP production from creatine phosphate would increase. 
C)  ADP production from creatine phosphate would decrease. 
D)  ADP production from creatine phosphate would increase. 
A)  ATP production from creatine phosphate would decrease. 
B)  ATP production from creatine phosphate would increase. 
C)  ADP production from creatine phosphate would decrease. 
D)  ADP production from creatine phosphate would increase.

Question 10

-What does "C" represent on the diagram?

Accepted Answer

A)  Threshold 
B)  Depolarization 
C)  Depolarization phase of action potential 
D)  Repolarization phase of action potential 
A)  Threshold 
B)  Depolarization 
C)  Depolarization phase of action potential 
D)  Repolarization phase of action potential

Question 11

If one nerve stimulus arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch, the most likely result will be ________.

Accepted Answer

A)  fatigue 
B)  spasm 
C)  incomplete tetanus 
D)  complete tetanus 
E)  flaccid paralysis 
A)  fatigue 
B)  spasm 
C)  incomplete tetanus 
D)  complete tetanus 
E)  flaccid paralysis

Question 12

A skeletal muscle generates the greatest tension when it is

Accepted Answer

A)  greatly stretched before being stimulated. 
B)  partially stretched before being stimulated. 
C)  fully relaxed before being stimulated. 
D)  well-rested and low in creatine phosphate. 
E)  high in lactate concentration. 
A)  greatly stretched before being stimulated. 
B)  partially stretched before being stimulated. 
C)  fully relaxed before being stimulated. 
D)  well-rested and low in creatine phosphate. 
E)  high in lactate concentration.

Question 13

One ATP molecule is required for

Accepted Answer

A)  formation of the cross-bridge. 
B)  movement of the cross-bridge. 
C)  release of the cross-bridge. 
D)  formation of the cross-bridge and for movement of the cross-bridge. 
E)  formation of the cross-bridge, for movement of the cross-bridge, and for release of the cross-bridge. 
A)  formation of the cross-bridge. 
B)  movement of the cross-bridge. 
C)  release of the cross-bridge. 
D)  formation of the cross-bridge and for movement of the cross-bridge. 
E)  formation of the cross-bridge, for movement of the cross-bridge, and for release of the cross-bridge.

Question 14

Which of the following descriptions best represents the appearance of the sarcomere during peak contraction?

Accepted Answer

A)  The H zone is eliminated, and the I bands are very thin. 
B)  The width of the A band is slightly less than the width of the I band. 
C)  The H zone is equivalent to one-third of the length of the A band. 
D)  The I bands and A bands are of equal widths. 
A)  The H zone is eliminated, and the I bands are very thin. 
B)  The width of the A band is slightly less than the width of the I band. 
C)  The H zone is equivalent to one-third of the length of the A band. 
D)  The I bands and A bands are of equal widths.

Question 15

Myasthenia gravis results from the destruction of acetylcholine receptors at the neuromuscular junction, but treatment involves medications that reduce acetylcholinesterase activity. Which statement best explains the effectiveness of these medications?

Accepted Answer

A)  The antibodies destroy some but not all of the acetylcholine receptors, so reducing acetylcholinesterase activity increases the likelihood that acetylcholine will bind to the remaining receptors. 
B)  Acetylcholinesterase is the substance that destroys the receptors as well, so reducing its activity increases the number of acetylcholine receptors. 
C)  Acetylcholinesterase breaks down the acetylcholine to a substance that can bind to the damaged receptors. 
D)  The antibodies that destroy the acetylcholine receptors are less likely to work if acetylcholinesterase is present. 
A)  The antibodies destroy some but not all of the acetylcholine receptors, so reducing acetylcholinesterase activity increases the likelihood that acetylcholine will bind to the remaining receptors. 
B)  Acetylcholinesterase is the substance that destroys the receptors as well, so reducing its activity increases the number of acetylcholine receptors. 
C)  Acetylcholinesterase breaks down the acetylcholine to a substance that can bind to the damaged receptors. 
D)  The antibodies that destroy the acetylcholine receptors are less likely to work if acetylcholinesterase is present.

Question 16

ATPase is found in

Accepted Answer

A)  F-actin strands. 
B)  G-actin globular units. 
C)  myosin heads. 
D)  tropomyosin grooves. 
E)  troponin molecules. 
A)  F-actin strands. 
B)  G-actin globular units. 
C)  myosin heads. 
D)  tropomyosin grooves. 
E)  troponin molecules.

Question 17

Which of the following is NOT true of muscular atrophy?

Accepted Answer

A)  It is irreversible. 
B)  It can be caused by disuse. 
C)  It can be caused by denervation. 
D)  Transcutaneous stimulation can help prevent it. 
E)  Muscle fibers are replaced by connective tissue. 
A)  It is irreversible. 
B)  It can be caused by disuse. 
C)  It can be caused by denervation. 
D)  Transcutaneous stimulation can help prevent it. 
E)  Muscle fibers are replaced by connective tissue.

Question 18

A lack of glycolytic enzymes within skeletal muscle fibers would impair which type of ATP-yielding process?

Accepted Answer

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

Question 19

Identify the statement concerning general functional characteristics of muscle that is true.

Accepted Answer

A)  Muscle tissue shortens forcefully but lengthens passively. 
B)  Muscle tissue shortens passively but lengthens forcefully. 
C)  Muscle tissue can get shorter, but cannot get longer. 
D)  Muscle tissue can get longer, but cannot get shorter. 
E)  None of these statements are true. 
A)  Muscle tissue shortens forcefully but lengthens passively. 
B)  Muscle tissue shortens passively but lengthens forcefully. 
C)  Muscle tissue can get shorter, but cannot get longer. 
D)  Muscle tissue can get longer, but cannot get shorter. 
E)  None of these statements are true.

Question 20

Skeletal muscle fibers

Accepted Answer

A)  possess striations. 
B)  can contract but are not extensible or excitable. 
C)  do not require nerve innervation to contract. 
D)  increase dramatically in number after birth. 
E)  are found in the walls of the stomach. 
A)  possess striations. 
B)  can contract but are not extensible or excitable. 
C)  do not require nerve innervation to contract. 
D)  increase dramatically in number after birth. 
E)  are found in the walls of the stomach.

Exam 9: Muscular System: Histology and Physiology

Skeletal muscle develops from cells called

A myofibril is the

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

-What does "D" represent on the diagram?

In excitation-contraction coupling,

The elevated oxygen consumption relative to activity level after exercise has ended is called

Curare blocks acetylcholine receptors at the motor end plate. This would result in

Which of the following statements best predicts the effect of a substance that blocks creatine kinase activity?

-What does "C" represent on the diagram?

If one nerve stimulus arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch, the most likely result will be ________.

A skeletal muscle generates the greatest tension when it is

One ATP molecule is required for

Which of the following descriptions best represents the appearance of the sarcomere during peak contraction?

Myasthenia gravis results from the destruction of acetylcholine receptors at the neuromuscular junction, but treatment involves medications that reduce acetylcholinesterase activity. Which statement best explains the effectiveness of these medications?

ATPase is found in

Which of the following is NOT true of muscular atrophy?

A lack of glycolytic enzymes within skeletal muscle fibers would impair which type of ATP-yielding process?

Identify the statement concerning general functional characteristics of muscle that is true.

Skeletal muscle fibers

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