Deck 8: Muscular System

Question 1

ATP is necessary for muscle relaxation.

Answer 1

True

Question 2

Troponin, tropomyosin and actin are all parts of the thin filaments.

Answer 2

True

Question 3

In the initiation ofmuscle contraction, calcium ions bind totropomyosin, exposing active sites on actin for cross-bridge formation.

Answer 3

False

Question 4

An isotonic contraction is one that involves a change in length but not a change in tension.

Question 5

The enzyme ATPase is located in the heads of myosin molecules.

Question 6

During the process of glycolysis, the breakdown of one glucose molecules results in production of two ATP molecules.

Question 7

Acetylcholine released by a motor neuron crosses the synaptic cleft and reaches the motor end plate by diffusion.

Question 8

Acetylcholinesterase breaks down the cross-bridge linkages between myosin to actin.

Question 9

Recruitment refers to increasing the number of motor units involved in a muscle contraction.

Question 10

Muscle fatigue results from a combination of insufficient calcium and an excessof acetylcholine.

Question 11

The enzyme ATPase is located in the heads of myosin molecules.

Question 12

Intercalated discs are found in skeletal muscle and cardiac muscle, but are not present in smooth muscle.

Question 13

The muscle most responsible for a particular movement is called the prime mover or antagonist.

Question 14

Cardiac muscle is located in the walls of blood vessels.

Question 15

If frequency of stimulation to a muscle fiber is increased, the force of contraction will increase.

Question 16

Endomysium separates individual muscle fibers from each other.

Question 17

An isotonic contraction is one that involves a change in length but not a change in tension.

Question 18

Endomysium separates individual muscle fibers from each other.

Question 19

Acetylcholine released by a motor neuron crosses the synaptic cleft and reaches the motor end plate by diffusion.

Question 20

In the initiation ofmuscle contraction, calcium ions bind totropomyosin, exposing active sites on actin for cross-bridge formation.

Question 21

How is creatine phosphate used by muscle cells?

A) It causes the decomposition of ATP.
B) It forms part of the thin filaments.
C) It is used to regenerate ATP.
D) It supplies energy for the breakdown ofATP to ADP.
E) It breaks down acetylcholine, allowing relaxation to occur.

Question 22

What is an example of a partial but sustained contraction of a whole muscle?

A) Blinking an eyelid
B) Tetanic contraction
C) Muscle twitch
D) Maintenance of posture
E) Motor unit fatigue

Question 23

ATP is necessary for muscle relaxation.

Question 24

Muscle fatigue results from a combination of insufficient calcium and an excessof acetylcholine.

Question 25

Intercalated discs are found in skeletal muscle and cardiac muscle, but are not present in smooth muscle.

Question 26

Troponin, tropomyosin and actin are all parts of the thin filaments.

Question 27

Acetylcholinesterase breaks down the cross-bridge linkages between myosin to actin.

Question 28

What forms the myofibrils of skeletal muscle cells?

A) Actin and myosin
B) ATP and ADP
C) Troponin and tropomyosin
D) Fascia and tendons
E) Perimysium and endomysium

Question 29

During the process of glycolysis, the breakdown of one glucose molecules results in production of two ATP molecules.

Question 30

What is the action of the enzyme acetylcholinesterase?

A) Needed for acetylcholine bind to troponin
B) Causes secretion of acetylcholine into synaptic cleft
C) Breaks down acetylcholine
D) Forms cross-bridge between acetylcholine molecules and acetylcholine receptors
E) Stimulates production of acetylcholine within synaptic vesicles

Question 31

If frequency of stimulation to a muscle fiber is increased, the force of contraction will increase.

Question 32

Cardiac muscle is located in the walls of blood vessels.

Question 33

Where are the vesicles that contain neurotransmitter molecules located?

A) Within sarcoplasmic reticulum
B) In synaptic cleft
C) On motor end plate membranes
D) In cytoplasm of motor neuron axon
E) At boundaries of sarcomeres

Question 34

The characteristic reddish color of skeletal muscle is due to the presence of what substance?

A) Actin
B) Myosin
C) Myoglobin
D) Calcium
E) Glycogen

Question 35

What binds to actin at its binding sites, allowing the formation of cross-bridges?

A) ATP
B) Myosin
C) Troponin
D) Tropomyosin
E) Creatine

Question 36

The muscle most responsible for a particular movement is called the prime mover or antagonist.

Question 37

Recruitment refers to increasing the number of motor units involved in a muscle contraction.

Question 38

By what means does an electrical impulse travel deep into a skeletal muscle fiber in order to trigger a contraction?

A) Via the sarcoplasmic reticulum
B) Via transverse tubules
C) Via mitochondria
D) Via motor end plates
E) Via gap junctions

Question 39

What structures form a motor unit?

A) Several motor neurons and one muscle fiber
B) One motor neuronand several muscle fibers
C) Several motor neurons and several muscle fibers

Question 40

What is oxygen debt?

A) The oxygen needed to oxidize one molecule of glucose during aerobic cellular respiration
B) The oxygen needed after strenuous exercise to restore ATP and oxygen levels, and for liver cells to convert lactate to glucose
C) The oxygen needed to begin a bout of strenuous exercise, starting from rest
D) The oxygen needed to drive glycolysis in muscle and liver cells
E) The oxygen needed to convert pyruvic acid to lactic acid to lactate

Question 41

What causes the rigor mortis that occurs in skeletal muscles after death?

A) Increase in available ATP, and decreased membrane permeability to calcium ions
B) Decrease in available ATP, and increased membrane permeability to calcium ions
C) Persistent stimulation by motor neuron
D) Decrease in the number of muscle fibers
E) Increase in membrane leakiness to sodium, resulting in continuing action potentials

Question 42

What is an alternate name for a skeletal muscle cell?

A) Myofibril
B) Myofilament
C) Myosin
D) Muscle fiber

Question 43

Layers of dense connective tissue called __________ separate and support individual muscles.

A) fascia
B) tendons
C) cartilage
D) aponeuroses

Question 44

What term refers to the increase in the number of motor units activated as a result ofmore intensestimulation?

A) Twitch
B) Recruitment
C) Threshold stimulation
D) All-or-none response
E) Summation

Question 45

What happens to a muscle that has lost its innervation?

A) It undergoes hypertrophy.
B) It stimulates the formation of new motor neurons.
C) It undergoes atrophy.
D) The muscle fibers enlarge in order to still undergo contraction.

Question 46

What is a threshold stimulus?

A) Minimum strength of stimulus required to cause muscle fiber contraction to occur
B) Maximal amount of force a muscle can exert
C) Amount of oxygen needed for repeated contractions
D) Minimal amount of force a muscle can exert
E) Maximal amount of stimulation a muscle can withstand

Question 47

Where would an antagonist to the sternocleidomastoidmuscles be located?

A) On the posterior side of the body
B) On the anterior side of the body
C) Inferior to the clavicle

Question 48

What term refers to the attachment point for the movable end of the muscle?

A) Origin
B) Fulcrum
C) Insertion
D) Motor end plate
E) Source

Question 49

In skeletal muscle, the thick filaments are mainly composed of ___________.

A) myosin
B) actin
C) myofibrils
D) sarcoplasm
E) Z lines

Question 50

What term describes the muscle that is primarily responsible for opposing a particular action?

A) Antagonist
B) Prime mover
C) Synergist
D) Agonist

Question 51

The muscles of the back that help maintain upright posture while standing still are undergoing what type of contractions?

A) Isotonic contractions
B) Isometric contractions

Question 52

What statement describes the zygomaticusmuscle?

A) It inserts on the coronoidprocess of the mandible.
B) It elevates the corner of the mouth.
C) It brings the head into an upright position.
D) It closes the lips.

Question 53

Activities such as distance swimming and distance running are most likely to stimulate the development of what type of muscle fiber?

A) Slow fibers
B) Fast fibers

Question 54

What is an action of the rectus femoris muscle?

A) Extends leg at knee
B) Plantar flexes the foot
C) Extends the thigh at the hip
D) Adducts the thigh

Question 55

Which statement describes multiunit smooth muscle?

A) Composed of sheets of muscle cells
B) Displays rhythmicity
C) Found within the walls of the stomach and intestines
D) Responds to stimulation by neurons and certain hormones

Question 56

Compared to skeletal muscle, smooth muscle contracts __________ and relaxes __________.

A) more slowly; more slowly
B) more slowly; more rapidly
C) more rapidly; more slowly
D) more rapidly; more rapidly

Question 57

What are fascicles?

A) Bundles of muscle fibers
B) Bundles of collagen fibers
C) Bundles of myofibrils
D) Bundles of thick and thin filaments
E) Bundles of smooth muscle cells

Question 58

In muscle anatomy, what is an origin?

A) The less movable end of a muscle
B) The more movable end of the muscle
C) The point of attachment of a tendon to a muscle
D) The location of a neuromuscular junction
E) The boundary between neighboring sarcomeres

Question 59

What structures consist of actin and myosin filaments?

A) Myofibrils
B) T tubules
C) Aponeuroses
D) Fascicles
E) Thick filaments

Question 60

A(n) __________ is a bundle of dense connective tissue that connects a skeletal muscle to a bone.

A) origin
B) insertion
C) tendon
D) ligament
E) epimysium

Question 61

What is the product of the anaerobic breakdown of glucose?

A) Creatine phosphate
B) Pyruvic acid
C) Carbon dioxide
D) Water and ATP

Question 62

What molecule, only present in muscle cells, is used to temporarily store oxygen for use in aerobic respiration?

A) Myoglobin
B) Acetylcholine
C) Creatine phosphate
D) Lactic acid
E) Pyruvic acid

Question 63

What is a description of the region known as the motor end plate?

A) It has many openings leading into transverse tubules.
B) Mitochondria are abundant.
C) Synaptic vesicles are abundant.
D) It functions to release neurotransmitter molecules.

Question 64

In skeletal muscle cells, what molecule can be used to transfer energy to ADP in order to form ATP?

A) Acetylcholine
B) Troponin
C) Actin
D) Creatinephosphate
E) Glucose

Question 65

Motor neurons communicate with muscle cells by releasing chemicals called ____________.

A) neurotransmitters
B) proteins
C) myosin
D) troponin
E) tropomyosin

Question 66

What type of neurons function to control effectors?

A) Aerobic neurons
B) Sensory neurons
C) Axon terminals
D) Motor neurons
E) Motor units

Question 67

What neurotransmitter is used to stimulate skeletal muscle contraction?

A) Norepinephrine
B) Actin
C) Acetylcholine
D) Tropomyosin
E) ATP

Question 68

The __________ is the gap that separates a muscle cell membrane from the neuron cell membrane in a neuromuscular junction.

A) synaptic cleft
B) T tubule
C) motor end plate
D) synaptic vesicle
E) sarcoplasm

Question 69

When acetylcholine binds to its receptors at the motor end plate, the muscle fiber membrane becomes more permeable to __________.

A) potassium
B) sodium
C) calcium
D) acetylcholine
E) acetylcholinesterase

Question 70

Following stenuous exercise, levels of ATP, creatine phosphate, oxygen, and glucose must be returned to normal levels. This situation, called __________, may take several hours to complete.

A) oxygen debt
B) muscle atrophy
C) aerobic respiration
D) tetany

Question 71

What enzyme catalyzes the breakdown of the neurotransmitter used to stimulate skeletal muscle?

A) Tropomyosin
B) ATPase
C) Acetylcholinesterase
D) Norephinephrine

Question 72

What is the product of the aerobic breakdown of glucose?

A) Creatine phosphate
B) Pyruvic acid
C) Lactic acid
D) Carbon dioxide, water, and ATP

Question 73

Enlarged portions of the sarcoplasmic reticulum are called __________.

A) synaptic clefts
B) cisternae
C) H zones
D) T tubules
E) motor end plates

Question 74

What structure within a skeletal muscle cell extends from Z line to Z line?

A) Sarcolemma
B) Sarcomere
C) Sarcoplasmic reticulum
D) A band
E) I band

Question 75

Name the membranouschannels or tunnels that extend inward from

A) Sarcomeres
B) Myofibrils
C) Transverse tubules
D) Cisternae
E) Motor end plates

Question 76

Skeletal muscle cells appear striated because of the presence of what parallel bundles?

A) Sarcomeres
B) Z lines
C) Myosin
D) Myofibrils
E) Transverse tubules

Question 77

What is the name of the functional connection between a motor neuron and a muscle cell?

A) Motor end plate
B) Synaptic cleft
C) Synaptic vesicle
D) Junctional plate
E) Neuromuscular junction

Question 78

In the absence of oxygen, what process is used by muscle cells to generate small amounts of ATP?

A) Electron transport chain
B) Glycolysis
C) Aerobic respiration
D) Hydrolysis of myoglobin

Question 79

What is the effect of an increased concentration of calcium ion in the sarcoplasm?

A) Actin binding sites become exposed.
B) Myosin binding sites become exposed.
C) Troponin binding sites become exposed.
D) Actin and myosin become unable to accomplish contraction.

Question 80

What is the main component of thin filaments?

A) Myofibrils
B) Acetylcholine
C) Actin
D) Myosin
E) Collagen