Deck 9: Muscular System

Question 1

Binding sites on the surface of actin allow the formation of cross-bridges with molecules of

A)ATP.
B)myosin.
C)troponin.
D)tropomyosin.

Answer 1

B

Question 2

The striated appearance of skeletal muscle fibers results from the

A)transverse tubule pattern.
B)sarcoplasmic reticulum network.
C)sarcomere organization.
D)cisternae placement.

Answer 2

C

Question 3

Organize the following muscular connective tissues from smallest to largest: epimysium, perimysium, fascia, endomysium.

A)Perimysium, epimysium, endomysium, fascia
B)Fascia, endomysium, perimysium, epimysium
C)Fascia, epimysium, perimysium, endomysium
D)Endomysium, perimysium, epimysium, fascia

Answer 3

D

Question 4

Muscle fibers are basically a collection of

A)muscles.
B)sarcomeres.
C)connective tissue fibers.
D)synapses.

Question 5

Myofibrils are composed primarily of

A)actin and myosin.
B)perimysium and endomysium.
C)troponin and tropomyosin.
D)fascia and tendons.

Question 6

Transverse tubules and sarcoplasmic reticulum are well developed in

A)smooth muscle fibers.
B)skeletal muscle fibers.
C)cardiac muscle fibers.
D)skeletal and cardiac muscle fibers.

Question 7

The discoloration and swelling that occurs with a muscle strain is due to

A)excess myofibrils.
B)separated tendons.
C)severed nerves.
D)ruptured blood vessels.

Question 8

Creatine phosphate

A)causes the decomposition of ATP.
B)causes the decomposition of ADP.
C)supplies energy for the synthesis of ATP.
D)supplies energy for the breakdown of ATP to ADP.

Question 9

The enzyme acetylecholinesterase causes acetylcholine to

A)bind to actin.
B)be secreted from the motor end plate.
C)decompose.
D)form cross-bridges.

Question 10

A sarcomere is best described as

A)a part of the sarcoplasmic reticulum.
B)a group of fascicles.
C)a group of muscle fibers.
D)a unit within a muscle fiber.

Question 11

The functional unit of muscle contraction is

A)the muscle.
B)the muscle fiber.
C)the myosin cross-bridge.
D)the sarcomere.

Question 12

The amount of oxygen liver cells require to support the conversion of lactic acid to produce glucose or glycogen is the

A)refractory quantity.
B)oxygen debt.
C)anaerobic concentration.
D)aerobic conversion.

Question 13

Functions of muscles include

A)pumping blood.
B)generating electrical impulses.
C)storage of minerals.
D)cushioning tissues from blunt force.

Question 14

Organize the following parts of a muscle from smallest to largest: muscle fiber, fascicle, myofibril, filament, muscle.

A)Myofibril, filament, muscle, fascicle, muscle fiber
B)Fascicle, filament, muscle fiber, myofibril, muscle
C)Filament, myofibril, muscle fiber, fascicle, muscle
D)Filament, muscle fiber, myofibril, fascicle, muscle

Question 15

A tendon is ________, whereas an aponeurosis is ________.

A)cordlike and connects bones to bones; a broad sheet of dense connective tissue that connects muscles to muscles
B)a broad sheet of dense connective tissue that connects muscles to muscles; cordlike and connects bones to bones
C)cordlike and connects muscles to bones; a broad sheet of dense connective tissue that connects muscles to muscles
D)a broad sheet of dense connective tissue that connects bones to bones; cordlike and connects muscles to muscles

Question 16

Neurotransmitters are stored in vesicles in

A)myofibrils.
B)motor units.
C)motor end plates.
D)motor neuron endings.

Question 17

The outermost layer of connective tissue surrounding a skeletal muscle is the

A)epimysium.
B)perimysium.
C)endomysium.
D)sarcomysium.

Question 18

Transverse tubules

A)store sodium ions for the action potential at the cell surface.
B)transmit muscle impulses into the cell interior.
C)store calcium ions.
D)connect actin and myosin.

Question 19

Certain natural plant poisons and animal venoms contain substances that inhibit the function of acetylcholinesterase. If a person is poisoned by one of these substances, which of the following will be the cause of their symptoms?

A)Their muscles won't be able to contract because no acetylcholine will be released from the neuronal membrane.
B)Their muscles will be in a constant state of contraction because acetylcholine won't be broken down and cleared from the neuromuscular junction.
C)Their muscles won't be able to contract because acetylcholine will be attacked and degraded immediately after release from the neuron.
D)Their muscles won't be able to contract because acetylcholine won't be properly synthesized by acetylcholinesterase.

Question 20

Tawanda finishes a sprint and suffers great pain in her calf muscles. Her muscle cramps are most likely due to a temporary deficit of

A)actin.
B)myosin.
C)ATP.
D)ADP.

Question 21

During strenuous exercise, muscles may not be supplied with enough oxygen, causing a shift in metabolism resulting in the breakdown of pyruvic acid to lactic acid. This change in metabolism is called the

A)aerobic threshold.
B)lactic acid threshold.
C)pyruvic acid threshold.
D)glycogenic threshold.

Question 22

What enzyme degrades acetylcholine, keeping it from accumulating in the synapse?

A)ATPase
B)Myosinase
C)Actinase
D)Acetylcholinesterase

Question 23

Oxygen debt in muscles may develop because of

A)the inability of respiratory and circulatory systems to supply enough oxygen to skeletal muscles when used strenuously for a minute or two.
B)the inability of myoglobin molecules to store enough oxygen when skeletal muscles are used strenuously for a minute or two.
C)too much oxygen used in forming pyruvic acid when skeletal muscles are contracted strenuously for a minute or two.
D)too high a concentration of oxygen in the atmosphere.

Question 24

Rigor mortis affects skeletal muscles a few hours after death, due to

A)an increase in ATP and decreased permeability to calcium.
B)a decrease in ATP and increased permeability to calcium.
C)an increase in ATP.
D)impulses that produce sustained contractions.

Question 25

As a person is vigorously rowing a boat, they suddenly experience extreme pain in their upper arm and no longer can extend at the elbow joint. Which of the following is probably the injured muscle?

A)Biceps brachii
B)Brachioradialis
C)Triceps brachii
D)Supinator

Question 26

Athletes usually experience muscle fatigue less quickly than nonathletes because they

A)convert glucose to lactic acid.
B)tolerate high concentrations of carbon dioxide.
C)make more efficient use of ATP.
D)produce less lactic acid.

Question 27

At a neuromuscular junction, the muscle fiber membrane folds, forming a

A)motor neuron.
B)neurotransmitter.
C)motor unit.
D)motor end plate.

Question 28

A runner collapses during a race and is examined by a doctor. They have lost the ability to plantar flex at the ankle. Which of the following is probably the injured muscle?

A)Gastrocnemius
B)Biceps femoris
C)Semimembranosus
D)Tibialis anterior

Question 29

Arrange the following steps of muscle fiber contraction in the correct sequence. 1. The muscle impulse reaches the sarcoplasmic reticulum and calcium is released.
2) Thin filaments are pulled over the thick filaments.
3) Calcium floods the sarcoplasm and binds to troponin molecules leaving active sites.
4) The impulse arrives at the synapse and travels through the transverse tubules.
5) The muscle fiber shortens and contracts.
6) Myosin heads bind to exposed active sites on actin, forming cross-bridges.

A)4, 1, 3, 5, 6, 2
B)4, 1, 3, 2, 6, 5
C)4, 1, 3, 6, 2, 5
D)4, 3, 6, 2, 5, 1

Question 30

A group of rats are bred in a laboratory to study muscle function. This group possesses a genetic defect that causes troponin to be incorrectly synthesized, making it non-functional. Because of this, the rats are entirely paralyzed. Which of the following correctly explains the impact of the defect on the muscle?

A)Troponin can't bind Ca⁺², which stops tropomyosin from pulling away to reveal actin binding spots on the thin filament.
B)Troponin, when revealed by tropomyosin, won't be able to bind to the myosin heads of the thick filament.
C)Troponin won't pull away to reveal the actin binding spots of the thin filament after tropomyosin binds Ca⁺².
D)Troponin, when revealed by actin, won't be able to bind to the myosin heads of the thick filament.

Question 31

The toxin that causes botulism

A)prevents release of acetylcholine.
B)promotes release of acetylcholine.
C)decomposes acetylcholine.
D)prevents decomposition of acetylcholine.

Question 32

When ATP levels are low, the relationship between ATP and creatine phosphate is that

A)ATP supplies energy to synthesize creatine phosphate from creatine and phosphate.
B)creatine phosphate supplies energy to regenerate ATP from ADP and phosphate.
C)both have three phosphate groups.
D)both are required to stimulate a muscle to contract.

Question 33

The characteristic reddish brown color of skeletal muscle comes from which substance?

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

Question 34

Many muscles are named for their location (origin and insertion)in the body, particularly in relation to bones. In what body region would you expect the frontalis muscle to originate?

A)The thoracic region
B)The abdominal region
C)The pelvic region
D)The cranium

Question 35

At a neuromuscular junction

A)actin and myosin filaments slide past one another.
B)troponin and tropomyosin exchange places.
C)neurotransmitters are released.
D)intercalated discs are synthesized.

Question 36

The functional connection between a neuron and a skeletal muscle fiber is a

A)synapse.
B)fascia.
C)neuroma.
D)dendrite.

Question 37

A group of rats are bred in a laboratory to study muscle function. This group possesses a genetic defect that causes the myosin heads to bind ADP irreversibly. The rats are entirely paralyzed. Which of the following correctly explains the impact of the defect on the muscle?

A)ATP won't bind to the myosin heads, preventing the actin binding site of the thick filament from being revealed.
B)Because ADP is permanently bound, the myosin heads can never bind to the actin binding sites of the thin filament.
C)Because ADP is permanently bound, the myosin heads will be irreversibly cross-bridged with the actin binding sites of the thin filament.
D)ATP won't bind to the myosin heads, causing the thin filament to be constantly pulled in the power stroke of contraction.

Question 38

Choose the correct statement about muscle contraction.

A)Tropomyosin molecules move and expose specific sites on myosin filaments.
B)Actin filaments slide along myosin filaments.
C)Cross-bridges form between actin and the sarcolemma.
D)Filaments of troponin and tropomyosin slide past one another.

Question 39

Muscle fibers generally only have one motor end plate, but motor neurons innervate many different muscle fibers in a group. Choose the statement that correctly explains how this affects muscle contraction.

A)While muscle fibers only have one motor end plate, they can recruit each other to contract once a fiber receives a signal.
B)When a motor neuron transmits a signal, only one fiber will contract with strong force.
C)A signal traveling through one motor neuron can potentially make multiple fibers in a group contract, generating more force.
D)The force of a contraction does not at all depend on the strength of the signal sent via the motor neuron.

Question 40

What is the first event in muscle fiber contraction?

A)The muscle fiber membrane is stimulated and a muscle impulse travels deep into the fiber through transverse tubules.
B)Acetylcholine diffuses across a gap at a neuromuscular junction.
C)Acetylcholine is released from the end of the motor neuron.
D)Calcium ions diffuse from sarcoplasmic reticulum into the sarcoplasm and bind to troponin molecules.

Question 41

A plank position is part of a yoga/Pilates workout. The person supports the body on the floor in a prone position with the arms and feet supporting the body. It is little similar to the "up" position of a push-up, held for 30 to 60 seconds. Contraction of the abdominal muscles in a plank is most likely

A)isotonic.
B)eccentric.
C)isometric.
D)concentric.

Question 42

A motor unit is

A)many myofibrils in a sarcolemma.
B)many motor end plates at a neuromuscular junction.
C)a motor neuron and the muscle fibers it innervates.
D)the functional unit of a muscle fiber.

Question 43

Activities such as distance swimming and distance running will most likely stimulate development of

A)slow fatigable muscle fibers.
B)fast fatigable muscle fibers.
C)slow fatigue-resistant fibers.
D)fast fatigue-resistant fibers.

Question 44

Short muscle cells with centrally located nuclei are

A)smooth muscle fibers.
B)skeletal muscle fibers.
C)cardiac muscle fibers.
D)striated muscle fibers.

Question 45

Compared to skeletal muscle, smooth muscle

A)contracts more slowly and relaxes more slowly.
B)contracts more slowly and relaxes more rapidly.
C)contracts more rapidly and relaxes more slowly.
D)contracts more rapidly and relaxes more rapidly.

Question 46

A muscle fiber exposed to a series of stimuli of increasing frequency combines individual twitches (summation)which results in

A)complete sustained contraction.
B)muscle tone.
C)a latent period.
D)flaccid muscles.

Question 47

Threshold stimulus is the

A)maximum stimulus required to release acetylcholine.
B)minimum stimulus required to produce ATP.
C)maximum stimulus required to contract a muscle.
D)minimum strength of stimulation required to contract a muscle fiber.

Question 48

The type of muscle cell that lacks transverse tubules, has a single nucleus, and is under involuntary control is

A)skeletal muscle.
B)smooth muscle.
C)cardiac muscle.
D)striated muscle.

Question 49

In a recording of a muscle twitch, the delay between the time a stimulus is applied and the time the muscle responds is called the

A)refractory period.
B)relaxation period.
C)latent period.
D)contraction period.

Question 50

Smooth muscle lacks

A)actin and myosin.
B)transverse tubules and striations.
C)myofibrils.
D)nuclei and mitochondria.

Question 51

A myogram is

A)a chart that shows how many muscle cells a neuron synapses with.
B)a recording of the events of a twitch.
C)a measurement of muscle tone.
D)a depiction of the results of a stress test.

Question 52

While examining a sample of muscle tissue under a microscope, you notice that the cells have a single nucleus. The fibers are striated and heavily branched. Which muscle type does this sample contain?

A)Skeletal muscle
B)Smooth muscle
C)Cardiac muscle
D)Striated muscle

Question 53

During muscle contraction, ATP supplies energy for

A)creatine phosphate synthesis.
B)glycogen synthesis.
C)myofilament movement.
D)enzyme activity.

Question 54

Which of the following is not true?

A)Red fibers contract more slowly than white.
B)Red fibers contain more myoglobin than white.
C)Red fibers have fewer mitochondria than white.
D)Red fibers fatigue more slowly than white.

Question 55

Smooth muscle has ________ and not troponin.

A)calmodulin
B)fibronectin
C)norepinephrine
D)titin

Question 56

The increase in the number of motor units activated as a result of more intense stimulation is called

A)latency.
B)recruitment.
C)threshold stimulation.
D)sustained contraction.

Question 57

When a muscle undergoes atrophy in response to disuse

A)motor neurons grow and invade abnormally.
B)the size of actin and myosin filaments decreases.
C)capillaries and vessels rupture.
D)the muscle swells.

Question 58

An example of a partial but sustained contraction is

A)knee jerking.
B)muscle tone.
C)a twitch.
D)eye blinking.

Question 59

Skeletal muscles help maintain body temperature in that

A)the more active they are, the more heat is used up.
B)the more active they are, the more heat is released.
C)excess myosin is quickly metabolized to yield heat.
D)they conserve actin and myosin in cold weather.

Question 60

While examining a sample of muscle tissue under a microscope, you notice that the cells are multinucleated. They are long, unbranched, striated, and contain a developed transverse tubule system. Which muscle type does this sample contain?

A)Skeletal muscle
B)Smooth muscle
C)Cardiac muscle
D)Striated muscle

Question 61

The more movable end of a muscle is its

A)origin.
B)fulcrum.
C)insertion.
D)source.

Question 62

The linea alba is

A)a muscle extending from the ischial spine to the coccyx and sacrum.
B)a curved, broad muscle on the side of the chest.
C)a muscle beneath the skull.
D)a band of tough connective tissue to which abdominal wall muscles attach.

Question 63

The soleus is a muscle that forms part of the

A)calf.
B)buttocks.
C)thigh.
D)shoulder.

Question 64

The muscle that adducts and flexes the arm is the

A)coracobrachialis.
B)pectoralis minor.
C)levator scapulae.
D)teres major.

Question 65

A gluteal gait, in which a person walks with a waddling limp, is usually caused by a disorder of the

A)gluteus maximus and gluteus medius.
B)gluteus maximus and gluteus minimus.
C)gluteus medius and gluteus minimus.
D)gluteus maximus and tensor fasciae latae.

Question 66

Muscle atrophy that progresses with aging is caused by reduction in 

A)muscle strength, but not motor neuron activity.
B)motor neuron activity, but not muscle strength.
C)connective tissues.
D)the sizes of muscle fibers.

Question 67

The triangle of auscultation, commonly used to hear sounds of respiratory organs, is located near the border of the

A)pectoralis major and pectoralis minor.
B)trapezius and latissimus dorsi.
C)latissimus dorsi and serratus anterior.
D)pectoralis major and serratus anterior.

Question 68

Cardiac muscle

A)is multinucleated.
B)excites itself.
C)contains only a few mitochondria.
D)partially lines the intestines.

Question 69

A muscle that assists the agonist is a(n)

A)antagonist.
B)prime mover.
C)mediator.
D)synergist.

Question 70

Both acetylcholine and norepinephrine can affect

A)smooth muscle contraction.
B)skeletal muscle contraction.
C)synthesis of actin and myosin.
D)exercise tolerance.

Question 71

Which of the following is unique in that its insertion is to fascia and not bone?

A)Palmaris longus
B)Extensor carpi ulnaris
C)Flexor digitorum profundus
D)Extensor digitorum

Question 72

A sign of aging of the muscular system is

A)expansion of muscle fiber diameters.
B)decreased supplies of myoglobin.
C)excess ATP.
D)increased creatine phosphate.

Question 73

The muscle that opposes a particular action is called the

A)synergist.
B)antagonist.
C)agonist.
D)prime mover.

Question 74

The buccinator muscle is in the

A)buttocks.
B)chest.
C)bladder.
D)cheek.

Question 75

Regina began an exercise program six months ago, and the muscles of her upper limbs and lower limbs are more prominent. Exercise can lead to formation of new muscle by

A)stimulating synthesis of myoglobin.
B)stimulating skeletal muscle cells to release IL-6, which stimulates satellite cells to divide, producing more muscle cells.
C)stimulating connective tissue to differentiate as muscle tissue.
D)stimulating motor neurons to divide and innervate more muscle cells.

Question 76

Which of the following is not a muscle of mastication?

A)Medial and lateral pterygoid
B)Masseter
C)Temporalis
D)Zygomaticus

Question 77

The muscle that causes an action is the

A)synergist.
B)antagonist.
C)agonist.
D)mediator.

Question 78

A mutation affecting cytokine development, particularly the interleukin-6 cytokine, will affect

A)bloodflow through muscles.
B)contraction force in muscles.
C)formation of new muscle from satellite cells.
D)muscle flexibility.

Question 79

Bones and muscles function as mechanical devices called

A)lifts.
B)levers.
C)syncytia.
D)ladders.

Question 80

The structures that connect cardiac muscle cells are

A)intervertebral discs.
B)neuromuscular junctions.
C)intercalated discs.
D)motor end plates.