Question 1

Endomysium is a delicate network of loose connective tissue that

Accepted Answer

A)  surrounds each muscle fiber. 
B)  forms a sheath around a fascicle. 
C)  is composed of elastic fibers. 
D)  separates individual muscles. 
E)  penetrates muscle fibers. 
A)  surrounds each muscle fiber. 
B)  forms a sheath around a fascicle. 
C)  is composed of elastic fibers. 
D)  separates individual muscles. 
E)  penetrates muscle fibers.

Question 2

Concentric contractions occur when

Accepted Answer

A)  the muscle produces increasing tension as it shortens. 
B)  the tension and length of the muscle remain constant during a contraction. 
C)  tension in a muscle is maintained while the muscle increases in length. 
D)  the muscle produces tension while the length of the muscle increases. 
E)  isometric contractions occur. 
A)  the muscle produces increasing tension as it shortens. 
B)  the tension and length of the muscle remain constant during a contraction. 
C)  tension in a muscle is maintained while the muscle increases in length. 
D)  the muscle produces tension while the length of the muscle increases. 
E)  isometric contractions occur.

Question 3

Which of the following is NOT a property of the myosin head?

Accepted Answer

A)  They form cross-bridges with the active sites of actin. 
B)  They have a hinge region to bend and straighten. 
C)  They bind to troponin. 
D)  They have ATPase activity. 
E)  They bind to ATP. 
A)  They form cross-bridges with the active sites of actin. 
B)  They have a hinge region to bend and straighten. 
C)  They bind to troponin. 
D)  They have ATPase activity. 
E)  They bind to ATP.

Question 4

As muscle activity increases, the body temperature ________.

Accepted Answer

A)  decreases 
B)  increases 
A)  decreases 
B)  increases

Question 5

Which of the following is NOT a function of skeletal muscle?

Accepted Answer

A)  Body movement 
B)  Maintenance of posture 
C)  Respiration 
D)  Constriction of organs 
E)  Production of heat 
A)  Body movement 
B)  Maintenance of posture 
C)  Respiration 
D)  Constriction of organs 
E)  Production of heat

Question 6

Atrophy at the neuromuscular junction that naturally occurs with age would have what effect on muscles?

Accepted Answer

A)  It would stimulate the nervous system to increase the speed in which it sends action potentials to the muscle fiber. 
B)  It would stimulate muscle cramps. 
C)  It would decrease the number of action potentials sent to the muscle fiber. 
D)  It would cause an increase in the amount of ACh released by the neurons to compensate. 
E)  It would have no effect on the muscles. 
A)  It would stimulate the nervous system to increase the speed in which it sends action potentials to the muscle fiber. 
B)  It would stimulate muscle cramps. 
C)  It would decrease the number of action potentials sent to the muscle fiber. 
D)  It would cause an increase in the amount of ACh released by the neurons to compensate. 
E)  It would have no effect on the muscles.

Question 7

Substance A is found to be a competitor with acetylcholine. Which step of muscle contraction physiology would be directly affected by this substance?

Accepted Answer

A)  Exposure of the active sites on G actin 
B)  Release of acetylcholine from the presynaptic terminal 
C)  Generation of an action potential at the sarcolemma 
D)  Release of the myosin head following the power stroke 
A)  Exposure of the active sites on G actin 
B)  Release of acetylcholine from the presynaptic terminal 
C)  Generation of an action potential at the sarcolemma 
D)  Release of the myosin head following the power stroke

Question 8

If Na+ cannot enter a muscle fiber in response to a stimulus,

Accepted Answer

A)  contraction cannot occur. 
B)  relaxation cannot occur. 
C)  Na+ will be released from the sarcoplasmic reticulum instead. 
D)  the active sites are left exposed. 
E)  the action potential travels into the muscle anyway. 
A)  contraction cannot occur. 
B)  relaxation cannot occur. 
C)  Na+ will be released from the sarcoplasmic reticulum instead. 
D)  the active sites are left exposed. 
E)  the action potential travels into the muscle anyway.

Question 9

What is tropomyosin?

Accepted Answer

A)  A protein found along the groove of the F-actin double helix 
B)  A T tubule and two adjacent terminal cisternae 
C)  The combination of myosin heads with active sites on actin molecules 
D)  The movement of myosin head while attached to actin myofilament 
E)  After exercise, the O2 taken in that exceeds the O2 required for resting metabolism 
A)  A protein found along the groove of the F-actin double helix 
B)  A T tubule and two adjacent terminal cisternae 
C)  The combination of myosin heads with active sites on actin molecules 
D)  The movement of myosin head while attached to actin myofilament 
E)  After exercise, the O2 taken in that exceeds the O2 required for resting metabolism

Question 10

Which of the following is part of a thin myofilament?

Accepted Answer

A)  ATP-binding site 
B)  Globular (G) actin 
C)  Calcium 
D)  Myosin 
E)  Sarcolemma 
A)  ATP-binding site 
B)  Globular (G) actin 
C)  Calcium 
D)  Myosin 
E)  Sarcolemma

Question 11

Actin myofilaments

Accepted Answer

A)  resemble bundles of minute golf clubs. 
B)  contain both myosin and tropomyosin. 
C)  are held in place by the M line. 
D)  contain strands of fibrous actin. 
E)  are the thickest proteins in muscle. 
A)  resemble bundles of minute golf clubs. 
B)  contain both myosin and tropomyosin. 
C)  are held in place by the M line. 
D)  contain strands of fibrous actin. 
E)  are the thickest proteins in muscle.

Question 12

Why does muscle activity affect the temperature of the body?

Accepted Answer

A)  The rate of chemical reactions increases in muscle fibers during contraction, so the rate of heat production also increases. 
B)  Muscle contraction generates pyrogens which reset the body's internal thermostat to a higher temperature. 
C)  Muscle activity directs more warm blood to the muscles away from the central core causing a cooling effect on your internal organs. 
D)  Increased muscle activity causes a rise in adipose stores which increases the insulation value of the body. 
A)  The rate of chemical reactions increases in muscle fibers during contraction, so the rate of heat production also increases. 
B)  Muscle contraction generates pyrogens which reset the body's internal thermostat to a higher temperature. 
C)  Muscle activity directs more warm blood to the muscles away from the central core causing a cooling effect on your internal organs. 
D)  Increased muscle activity causes a rise in adipose stores which increases the insulation value of the body.

Question 13

Which of the following is composed of myosin molecules?

Accepted Answer

A)  Thick myofilaments 
B)  I bands 
C)  Z disks 
D)  Sarcolemma 
E)  Tropomyosin 
A)  Thick myofilaments 
B)  I bands 
C)  Z disks 
D)  Sarcolemma 
E)  Tropomyosin

Question 14

When repolarization of the plasma membrane is complete, the

Accepted Answer

A)  cell dies. 
B)  cell regenerates. 
C)  cell no longer has a potential difference across its membrane. 
D)  cell is no longer responsive. 
E)  original polarity of the cell is restored. 
A)  cell dies. 
B)  cell regenerates. 
C)  cell no longer has a potential difference across its membrane. 
D)  cell is no longer responsive. 
E)  original polarity of the cell is restored.

Question 15

Myosin phosphatase

Accepted Answer

A)  activates myosin kinase. 
B)  forms the cross-bridge. 
C)  removes phosphate from myosin. 
D)  binds to calcium-calmodulin complex. 
E)  opens Ca2+-channels. 
A)  activates myosin kinase. 
B)  forms the cross-bridge. 
C)  removes phosphate from myosin. 
D)  binds to calcium-calmodulin complex. 
E)  opens Ca2+-channels.

Question 16

The type of muscle fatigue known as "psychological fatigue" is the result of

Accepted Answer

A)  depleted ATP reserves. 
B)  increased Ca2+ concentration in the sarcoplasm. 
C)  decreased levels of acetylcholine. 
D)  the emotional state of an individual. 
E)  None of these choices are correct. 
A)  depleted ATP reserves. 
B)  increased Ca2+ concentration in the sarcoplasm. 
C)  decreased levels of acetylcholine. 
D)  the emotional state of an individual. 
E)  None of these choices are correct.

Question 17

When the myosin head flexes into a bend, pulling the actin filament along with it, this is called the

Accepted Answer

A)  action reaction. 
B)  power stroke. 
C)  recovery stroke. 
D)  muscle tone. 
E)  action potential. 
A)  action reaction. 
B)  power stroke. 
C)  recovery stroke. 
D)  muscle tone. 
E)  action potential.

Question 18

-What does "A" 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 19

Channels that open or close in response to changes in the electrical charge or voltage across the plasma membrane are called

Accepted Answer

A)  ligand-gated ion channels. 
B)  leak ion channels. 
C)  relegated ion channels. 
D)  voltage-gated ion channels. 
E)  obligated ion channels. 
A)  ligand-gated ion channels. 
B)  leak ion channels. 
C)  relegated ion channels. 
D)  voltage-gated ion channels. 
E)  obligated ion channels.

Question 20

Which of the following will respond to a threshold stimulus with an all-or-none contraction?

Accepted Answer

A)  A single muscle fiber 
B)  A single motor unit 
C)  A whole muscle 
D)  Both a single muscle fiber and a single motor unit are correct. 
E)  A single muscle fiber, a single motor unit, and a whole muscle are all correct. 
A)  A single muscle fiber 
B)  A single motor unit 
C)  A whole muscle 
D)  Both a single muscle fiber and a single motor unit are correct. 
E)  A single muscle fiber, a single motor unit, and a whole muscle are all correct.

Exam 9: Muscular System: Histology and Physiology

Endomysium is a delicate network of loose connective tissue that

Concentric contractions occur when

Which of the following is NOT a property of the myosin head?

As muscle activity increases, the body temperature ________.

Which of the following is NOT a function of skeletal muscle?

Atrophy at the neuromuscular junction that naturally occurs with age would have what effect on muscles?

Substance A is found to be a competitor with acetylcholine. Which step of muscle contraction physiology would be directly affected by this substance?

If Na+ cannot enter a muscle fiber in response to a stimulus,

What is tropomyosin?

Which of the following is part of a thin myofilament?

Actin myofilaments

Why does muscle activity affect the temperature of the body?

Which of the following is composed of myosin molecules?

When repolarization of the plasma membrane is complete, the

Myosin phosphatase

The type of muscle fatigue known as "psychological fatigue" is the result of

When the myosin head flexes into a bend, pulling the actin filament along with it, this is called the

-What does "A" represent on the diagram?

Channels that open or close in response to changes in the electrical charge or voltage across the plasma membrane are called

Which of the following will respond to a threshold stimulus with an all-or-none contraction?

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

If Na⁺ cannot enter a muscle fiber in response to a stimulus,