Question 1

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 body of neuron. 
A)  neuromuscular junctions. 
B)  sarcomeres. 
C)  myofilaments. 
D)  Z disks. 
E)  cell body of neuron.

Question 2

What is a cross-bridge?

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 oxygen taken in that exceeds the oxygen 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 oxygen taken in that exceeds the oxygen required for resting metabolism

Question 3

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 these 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 these are true.

Question 4

-What does "D" represent on the diagram?

Accepted Answer

A)  myosin myofilament 
B)  actin myofilament 
C)  sarcomere 
D)  Z disk 
E)  cross-bridge 
A)  myosin myofilament 
B)  actin myofilament 
C)  sarcomere 
D)  Z disk 
E)  cross-bridge

Question 5

The sarcoplasmic reticulum

Accepted Answer

A)  stores calcium ions. 
B)  shortens during muscle contraction. 
C)  transmits nerve impulses to the myofibrils. 
D)  connects adjacent sarcomeres. 
E)  covers the muscle fiber. 
A)  stores calcium ions. 
B)  shortens during muscle contraction. 
C)  transmits nerve impulses to the myofibrils. 
D)  connects adjacent sarcomeres. 
E)  covers the muscle fiber.

Question 6

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

Accepted Answer

A)  skeletal muscle 
B)  smooth muscle 
C)  cardiac muscle 
A)  skeletal muscle 
B)  smooth muscle 
C)  cardiac muscle

Question 7

A drug that interferes with the active transport of calcium ions 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. 
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.

Question 8

-The figure illustrates the neuromuscular junction. What does "B" represent?

Accepted Answer

A)  presynaptic terminal 
B)  muscle fiber 
C)  neuromuscular junction 
D)  axon branch 
E)  myofibrils 
A)  presynaptic terminal 
B)  muscle fiber 
C)  neuromuscular junction 
D)  axon branch 
E)  myofibrils

Question 9

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 10

Which of the following is true?

Accepted Answer

A)  The greater the overlap of actin and myosin, the stronger the contraction. 
B)  Overstretching a muscle will increase its tension. 
C)  Optimal actin and myosin overlap will produce maximal contraction. 
D)  The greatest amount of tension is achieved when actin and myosin do not overlap. 
E)  Tension is great when actin and myosin overlap as much as they can. 
A)  The greater the overlap of actin and myosin, the stronger the contraction. 
B)  Overstretching a muscle will increase its tension. 
C)  Optimal actin and myosin overlap will produce maximal contraction. 
D)  The greatest amount of tension is achieved when actin and myosin do not overlap. 
E)  Tension is great when actin and myosin overlap as much as they can.

Question 11

In smooth muscle, most of the calcium needed for muscle contraction

Accepted Answer

A)  is in the dense bodies. 
B)  enters from extracellular fluid. 
C)  is attached to the intermediate filaments. 
D)  must be activated by myosin kinase. 
E)  is stored in the sarcoplasmic reticulum. 
A)  is in the dense bodies. 
B)  enters from extracellular fluid. 
C)  is attached to the intermediate filaments. 
D)  must be activated by myosin kinase. 
E)  is stored in the sarcoplasmic reticulum.

Question 12

Functionally, smooth muscle

Accepted Answer

A)  is well adapted to anaerobic metabolism. 
B)  exhibits autorhythmic contractions. 
C)  contracts in response to slow increases in length. 
D)  is unable to maintain tone. 
E)  rapidly develops an oxygen debt. 
A)  is well adapted to anaerobic metabolism. 
B)  exhibits autorhythmic contractions. 
C)  contracts in response to slow increases in length. 
D)  is unable to maintain tone. 
E)  rapidly develops an oxygen debt.

Question 13

Lack of acetylcholinesterase in the synaptic cleft would result in

Accepted Answer

A)  a decrease in acetylcholine production by the motor neuron. 
B)  continuous stimulation of the postsynaptic membrane. 
C)  rapid degradation of acetylcholine. 
D)  relaxation of the muscle. 
E)  continuous stimulation of the presynaptic membrane. 
A)  a decrease in acetylcholine production by the motor neuron. 
B)  continuous stimulation of the postsynaptic membrane. 
C)  rapid degradation of acetylcholine. 
D)  relaxation of the muscle. 
E)  continuous stimulation of the presynaptic membrane.

Question 14

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. 
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.

Question 15

Rigor mortis occurs after death because

Accepted Answer

A)  cross-bridges form but can't release. 
B)  calcium is actively transported back to the sarcoplasmic reticulum. 
C)  anaerobic respiration is occurring. 
D)  myosin levels decline at death. 
E)  cross-bridges never form. 
A)  cross-bridges form but can't release. 
B)  calcium is actively transported back to the sarcoplasmic reticulum. 
C)  anaerobic respiration is occurring. 
D)  myosin levels decline at death. 
E)  cross-bridges never form.

Question 16

The time between application of the stimulus to a motor neuron and the beginning of contraction is called the _____ phase.

Accepted Answer

A)  contraction 
B)  relaxation 
C)  latent or lag 
D)  refractory 
E)  threshold 
A)  contraction 
B)  relaxation 
C)  latent or lag 
D)  refractory 
E)  threshold

Question 17

A condition in which stimuli occur so rapidly that there are no intervening relaxations between contractions is called

Accepted Answer

A)  complete tetanus. 
B)  incomplete tetanus. 
C)  involuntary paralysis. 
D)  all or none tetanus. 
E)  treppe. 
A)  complete tetanus. 
B)  incomplete tetanus. 
C)  involuntary paralysis. 
D)  all or none tetanus. 
E)  treppe.

Question 18

What are dense bodies and intermediate filaments in smooth muscle?

Accepted Answer

A)  can rapidly develop action potentials 
B)  shallow invaginations of cell membrane 
C)  relatively constant tension maintained for a period of time 
D)  intracellular cytoskeleton 
E)  enzyme that removes phosphate from myosin 
A)  can rapidly develop action potentials 
B)  shallow invaginations of cell membrane 
C)  relatively constant tension maintained for a period of time 
D)  intracellular cytoskeleton 
E)  enzyme that removes phosphate from myosin

Question 19

Which type of muscle tissue causes contraction of the heart?

Accepted Answer

A)  skeletal muscle 
B)  smooth muscle 
C)  cardiac muscle 
A)  skeletal muscle 
B)  smooth muscle 
C)  cardiac muscle

Question 20

-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

Exam 9: Muscular System: Histology and Physiology

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

What is a cross-bridge?

Which of the following is true about skeletal muscle?

-What does "D" represent on the diagram?

The sarcoplasmic reticulum

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

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

-The figure illustrates the neuromuscular junction. What does "B" represent?

Which of the following is true?

Which of the following is true?

In smooth muscle, most of the calcium needed for muscle contraction

Functionally, smooth muscle

Lack of acetylcholinesterase in the synaptic cleft would result in

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

Rigor mortis occurs after death because

The time between application of the stimulus to a motor neuron and the beginning of contraction is called the _____ phase.

A condition in which stimuli occur so rapidly that there are no intervening relaxations between contractions is called

What are dense bodies and intermediate filaments in smooth muscle?

Which type of muscle tissue causes contraction of the heart?

-What does "C" represent on the diagram?

The Human Organism

The Chemical Basis of Life

Cell Biology

Tissues

Integumentary System

Skeletal System: Bones and Bone Tissue

Skeletal System: Gross Anatomy

Joints 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, Electrolytes, and Acidbase Balance

Reproductive System

Development, Growth, Aging, and Genetics

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