Deck 7: Muscular System

Question 1

Which of the following characteristics would establish conclusively that muscle tissue being examined was skeletal muscle tissue?

A) several nuclei per cell
B) striations present
C) contracts spontaneously
D) intercalated disks present
E) under involuntary control

Answer 1

A

Question 2

The letter B in this figure represents

A) action potential.
B) synaptic vesicles.
C) acetylcholine molecules.
D) synaptic cleft.
E) sodium ions.

Answer 2

E

Question 3

A muscle fiber will not respond to a stimulus until that stimulus reaches the

A) tetany.
B) relaxation level.
C) rigor mortis level.
D) threshold level.
E) recruitment level.

Answer 3

D

Question 4

The __________ is attached to bones via tendons.

A) myofilament
B) myofibril
C) muscle fiber
D) muscle fasciculus
E) whole skeletal muscle

Question 5

The letter A in this figure represents

A) the A band.
B) the M line.
C) a sarcomere.
D) the I band.
E) a Z disk.

Question 6

The ___________ is a group of muscle cells surrounded by perimysium.

A) myofilament
B) myofibril
C) muscle fiber
D) muscle fasciculus
E) whole skeletal muscle

Question 7

The letter A in this figure represents the

A) action potential.
B) synaptic vesicles.
C) acetylcholine molecules.
D) synaptic cleft.
E) sodium ions.

Question 8

Actin myofilaments

A) resemble bundles of minute golf clubs.
B) are attached to Z lines at one end.
C) form the I band where actin overlaps with myosin myofilaments.
D) form the epimysium.
E) have all of these characteristics.

Question 9

A _________ is a single muscle cell.

A) myofilament
B) myofibril
C) muscle fiber
D) muscle fasciculus
E) whole skeletal muscle

Question 10

Connective tissue that surrounds the fasciculi is called

A) perimysium.
B) endomysium.
C) fascia.
D) fasciculi.
E) microfibrils.

Question 11

The myosin myofilaments are anchored into the cytoskeleton of the cell by the __________.

A) Z disks
B) A band
C) M line
D) I band
E) H zone

Question 12

The ____________ consists of only actin myofilaments.

A) A band
B) I band
C) H zone
D) M line
E) Z disk

Question 13

Muscle fibers

A) have a relatively high metabolic rate
B) depend upon large amounts of O₂
C) contain large numbers of mitochondria
D) preferentially use aerobic respiration
E) all of these are true of muscle fibers

Question 14

The letter B in this figure points to

A) the A band.
B) the M line.
C) a sarcomere.
D) the I band.
E) a Z disk.

Question 15

The ________ is the functional unit of skeletal muscle because it is the smallest portion of the skeletal muscle capable of ___________.

A) muscle fiber, receiving a stimulus
B) muscle fiber, contracting
C) sarcomere, contracting
D) sarcomere, receiving a stimulus
E) myofibril, contracting

Question 16

The actin myofilaments are anchored into the cytoskeleton of the cell by the __________.

A) Z disks
B) A band
C) M line
D) I band
E) H zone

Question 17

The _________ is the smooth ER of a muscle fiber and stores calcium ions.

A) sarcolemma
B) sarcoplasmic reticulum
C) sarcomere
D) sarcoplasm
E) T tubules

Question 18

All of the following are the effects of aging on the muscular system EXCEPT:

A) reduction in muscle mass
B) increase in response time to stimulus
C) reduction in number of motor units
D) reduction in surface area of the neuromuscular junction
E) increase in the number of myofilaments in each fiber

Question 19

Acetylcholine

A) is the neurotransmitter at the neuromuscular junction.
B) is broken down by acetylcholinesterase.
C) binds to receptors on the muscle cell membrane.
D) causes an influx of sodium ions into the muscle cell when bound to its receptor.
E) has all of these characteristics.

Question 20

The specific molecules that provide calcium binding sites on actin are __________ molecules.

A) troponin
B) tropomyosin
C) titin
D) myosin

Question 21

In muscles, a high-energy molecule that can be quickly used to produce ATP is

A) creatine phosphate.
B) glucose.
C) carbon dioxide.
D) lactic acid.
E) water.

Question 22

The primary muscle(s) responsible for elevating the ribs during inspiration is (are)

A) the diaphragm.
B) the external intercostals.
C) the rectus abdominis.
D) the internal intercostals.
E) the erector spinae.

Question 23

Aerobic respiration

A) results in the breakdown of glucose to yield ATP and lactic acid.
B) is much less efficient than anaerobic respiration
C) can use fatty acids and amino acids to generate ATP
D) can occur much faster than anaerobic respiration
E) all of the above are true of aerobic respiration

Question 24

Aerobic respiration:

A) requires oxygen
B) breaks down glucose
C) produces ATP, CO₂ and H₂O
D) takes place in mitochondria located within the muscle fiber sarcoplasm
E) all of these are true of aerobic respiration

Question 25

Caffeine aids in the movement of calcium ions across membranes by both making it easier for the Ca⁺⁺ channels to open and by holding the channels open longer. How would the administration of caffeine to a muscle fiber affect its contraction?

A) Caffeine would increase the strength of the fiber's contraction.
B) Caffeine would allow more cross bridges to form in the fiber.
C) Caffeine would increase the duration of the fiber's contraction.
D) At high enough levels, caffeine would cause the muscle fiber to contract without a signal from the associated motor neuron.
E) Caffeine would have all of these effects.

Question 26

Which of the following muscles are used to elevate the larynx?

A) the masseter
B) the soft palate muscles
C) the hyoid muscles
D) the pharyngeal constrictors
E) the sternocleidomastoid

Question 27

The normal resting cell membrane is the most permeable to

A) sodium ions
B) potassium ions
C) negatively charged proteins
D) calcium ions
E) magnesium ions

Question 28

Creatine phosphate

A) is produced by the process of anaerobic respiration.
B) can replace ATP in binding myosin molecules during contraction.
C) acts as an energy reserve in muscle tissue.
D) is only formed during strenuous exercise.
E) causes the build up of lactic acid.

Question 29

Curare is a poison used by South American Indians. It is known to bind to ACh receptors preventing the binding of ACh. What effect would it have on muscle function?

A) The muscle fibers would contract uncontrollably and continually.
B) The muscle fibers would not contract because the Na⁺ channels which cause depolarization of the muscle fiber membrane are never signaled to open.
C) The pre-synaptic release of ACh would be inhibited, therefore the muscle would not contract.
D) The action of acetylcholinesterase would be inhibited causing increased contraction.
E) Both the muscle fibers would contract uncontrollably and continually and the action of acetylcholinesterase would be inhibited causing increased contraction would occur.

Question 30

In a resting cell, K⁺ ions have a higher concentration ______ the cell, which results in the net movement of K⁺ _______ of the cell.

A) inside; out
B) outside; into
C) inside; into
D) outside; out

Question 31

What are the relative concentrations of Na⁺, K⁺ and dissolved proteins in the intracellular solution (i.e. cytosol) as opposed to in the extracellular fluid?

A) $\uparrow$ Na⁺, $\uparrow$ K⁺, and $\uparrow$ dissolved proteins inside the cell
B) $\uparrow$ Na⁺, $\downarrow$ K⁺, and $\uparrow$ dissolved proteins inside the cell
C) $\downarrow$ Na⁺, $\uparrow$ K⁺, and $\uparrow$ dissolved proteins inside the cell
D) $\downarrow$ Na⁺, $\downarrow$ K⁺, and $\downarrow$ dissolved proteins inside the cell

Question 32

Smooth muscle

A) has no distinct sarcomeres.
B) contracts more slowly than skeletal muscle.
C) may be autorhythmic.
D) does not develop an oxygen deficit.
E) has all of these characteristics.

Question 33

ATP

A) attaches to the myosin myofilaments.
B) provides energy for the movement of the cross bridges.
C) is required for muscle relaxation.
D) releases part of its energy as heat.
E) has all of these characteristics.

Question 34

Which of these muscles is NOT a fixator of the scapula?

A) latissimus dorsi
B) trapezius
C) levator scapulae
D) serratus anterior
E) pectoralis minor

Question 35

The biceps brachii muscle and the triceps brachii muscle

A) are synergists.
B) are antagonists.
C) both flex the forearm.
D) are both antagonists and flexors of the forearm.
E) are both synergists and flexors of the forearm.

Question 36

If someone winks at you, they are using their

A) zygomaticus muscles.
B) occipitofrontalis muscle.
C) orbicularis oculi.
D) depressor anguli oris.
E) orbicularis oris.

Question 37

Cardiac muscle

A) is under involuntary control.
B) has long, cylindrical cells
C) has many nuclei per cell.
D) has no striations.
E) has all of these characteristics.

Question 38

What would happen if the cell membrane suddenly became impermeable to K⁺ ions?

A) The outside of the cell membrane would become more positively charged.
B) The cell would become more negatively charged.
C) The cell would become more positively charged.
D) The cell would depolarize.
E) The outside of the cell membrane would become more positively charged and the cell would depolarize are correct.

Question 39

In skeletal muscle contraction and relaxation, calcium ions

A) bind to myosin myofilaments.
B) are returned to the sarcoplasmic reticulum by active transport.
C) are released from the T tubules by active transport.
D) provide the energy for muscle contraction.
E) have both bind to myosin myofilaments and are returned to the sarcoplasmic reticulum by active transport as normal properties.

Question 40

Which of the following statements is FALSE?

A) The resting potential of a cell develops because the cell membrane is more permeable to K⁺ than it is to most other ions.
B) The concentration of Na⁺ is higher inside the cell than outside.
C) Potassium ions only diffuse down their gradient until the charge difference across the membrane is great enough (electrical equilibrium) to prevent additional diffusion.
D) Potassium's tendency to diffuse out is opposed by the attractive forces of the negative charge inside the cell.
E) The sodium-potassium exchange pump maintains the normal resting concentrations of ions on either side of the cell membrane.

Question 41

Organophospahtes cause spastic paralysis because:

A) their action produces a constant stimulus to contract
B) they inhibit the activity of acetylcholinesterase
C) they prevent the degradation of acetylcholine in the neuromuscular junction
D) they prevent the muscles from relaxing
E) all of these are true

Question 42

Which of the following statements is FALSE?

A) When muscles contract, the actin myofilaments are pulled towards the M-lines (the center), thus decreasing the overall sarcomere length.
B) During muscle contraction, the actual length of the actin and myosin molecules changes.
C) The sarcolemma is a specialized plasma membrane of a muscle cell.
D) A muscle cell is also called a muscle fiber.
E) Normally, skeletal muscle fibers do not contract unless they are stimulated by motor neurons.

Question 43

Given these events: 1) calcium ions move along their concentration gradient
2) action potential in cell membrane
3) opening of ion channels in sarcoplasmic reticulum
4) action potential in T tubules
5) actin to myosin cross-bridges form
Arrange them in the correct sequence as they participate during skeletal muscle contraction.

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

Question 44

The ____________ is a muscle in a group that plays a major role in a desired movement.

A) origin
B) insertion
C) agonist
D) antagonist
E) prime mover

Question 45

Muscles are named according to their

A) location or number of heads.
B) function or action.
C) origin or insertion point.
D) size or shape.
E) Muscles can be named based on all of these features.

Question 46

The major abductor of the upper limb is the

A) trapezius.
B) latissimus dorsi.
C) deltoid.
D) pectoralis major.
E) biceps brachii.

Question 47

The hip muscle commonly used as a site for injections is the

A) gluteus maximus.
B) gluteus medius.
C) iliopsoas.
D) tensor fascia latae.
E) hamstring muscle.

Question 48

"Pull-ups" are easier to do with the hands supinated than with the hands pronated. An explanation for this is

A) the biceps brachii is attached to the radial tuberosity.
B) the biceps brachii supinates the forearm.
C) if the forearm is pronated, the biceps brachii is ineffective in flexing the forearm.
D) the brachialis is a much smaller muscle than the biceps brachii.
E) All of these contribute to a full and proper explanation.

Question 49

The condition in which a muscle remains contracted between stimuli without relaxing is called

A) recruitment.
B) tetanus.
C) the all-or-none response.
D) a motor unit.
E) the lag phase.

Question 50

An anterior thigh muscle that extends the leg is the

A) sartorius.
B) quadriceps femoris.
C) hamstring group.
D) adductor group.
E) iliopsoas.

Question 51

Carl Daver, your anatomy and physiology instructor, is conducting a field trip, and notices a dog approaching a fire hydrant. Always alert to instructional opportunities, he excitedly says, "Now watch as the dog utilizes his _____ and _____ muscles to lift his leg."

A) iliopsoas, gluteus medius
B) gluteus maximus, tensor fascia latae
C) gluteus maximus, adductor longus
D) iliopsoas, quadriceps femoris
E) gluteus medius, adductor longus

Question 52

The ____________ is the end of a muscle attached to a bone undergoing the greatest movement.

A) origin
B) insertion
C) agonist
D) antagonist
E) prime mover

Question 53

A condition known as flaccid paralysis:

A) arises because the muscle is incapable of contracting in response to nervous stimulation
B) arises because acetylcholinesterase levels are artificially low
C) arises because the muscle is incapable of relaxing
D) arises because acetylcholine in the neuromuscular junction never breaks down
E) all of these are true.

Question 54

Muscles that work together to cause movement are called

A) origins.
B) insertions.
C) synergists.
D) antagonists.
E) prime movers.

Question 55

Contractibility is the ability of skeletal muscle to

A) shorten with force.
B) lengthen passively.
C) respond to a stimulus.
D) recoil to their original resting length.
E) be stretched.

Question 56

The anterior hip muscle that flexes the thigh is the

A) iliopsoas.
B) gluteus medius.
C) tensor fascia latae.
D) gluteus maximus.
E) entire gluteal group.

Question 57

Slow-twitch muscle fibers

A) are the predominant type of muscle fibers in the upper limbs.
B) have a richer blood supply than fast twitch fibers, and contain myoglobin.
C) would be used for activities resulting in (or requiring) anaerobic respiration.
D) fatigue more easily than fast-twitch fibers.
E) have all of these characteristics.

Question 58

The muscle that works in opposition to another muscle is the

A) origin.
B) insertion.
C) agonist.
D) antagonist.
E) prime mover.

Question 59

The characteristic that allows muscles to have a slow, smooth, sustained contraction is

A) the all-or-none response.
B) temporal summation.
C) recruitment of motor units.
D) anaerobic respiration.
E) rigor mortis.

Question 60

A single motor neuron and all the skeletal muscle fibers it innervates is called a

A) neuromuscular junction.
B) synaptic cleft.
C) motor unit.
D) synapse.
E) presynaptic terminal.

Question 61

In __________ contraction the amount of tension increases during contraction, but the length of the muscle does not change.

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

Question 62

Extensibility is the ability of skeletal muscle to

A) shorten with force.
B) respond to a stimulus.
C) recoil to their original resting length.
D) be stretched.
E) create heat energy through contraction.

Question 63

Satellite cells:

A) are undifferentiated cells below the endomysium
B) can differentiate and divide into new functional muscle fibers
C) are stimulated by the destruction of existing muscle fibers
D) are stimulated by intensive strength training
E) all of these are true of satellite cells

Question 64

What ensures that one action potential in the neuron yields only one action potential in the skeletal muscle fibers of the stimulated motor unit and therefore only one contraction per fiber?

A) the amount of calcium that enters the pre-synaptic cell
B) the rate of diffusion of acetylcholine across the synaptic cleft
C) the number of muscle fibers that make up the motor unit
D) enzymatic breakdown of acetylcholine by acetylcholinesterase
E) All of these ensure this one to one ratio.

Question 65

Excitability is the ability of skeletal muscle to

A) shorten with force.
B) lengthen passively.
C) respond to a stimulus.
D) recoil to their original resting length.
E) be stretched.

Question 66

In a neuromuscular junction,

A) the presynaptic terminal is separated from the postsynaptic terminal by the synaptic cleft.
B) the presynaptic terminal contains vesicles filled with sodium ions.
C) the presynaptic terminal contains receptor molecules for the neurotransmitter.
D) the neurotransmitter causes an action potential in the presynaptic terminal.
E) all of these conditions occur.

Question 67

Elasticity is the ability of skeletal muscle to

A) shorten with force.
B) lengthen passively.
C) respond to a stimulus.
D) recoil to their original resting length.
E) generate new collagen fibers.

Question 68

Which of the following muscles most likely contains motor units that are relatively small (motor neurons that innervate only a small number of muscle fibers each)?

A) the biceps femoris.
B) the trapezius.
C) the intrinsic hand muscles.
D) the latissimus dorsi
E) the sternocleidomastoid.

Question 69

A chemical that is considered an acetylcholine antagonist:

A) increases the activity of acetylcholine
B) decreases or prevents the activity of acetylcholine
C) magnifies the effect of acetylcholine on the neuromuscular junction
D) causes the release of acetylcholine
E) magnifies the effect of acetylcholine on the neuromuscular junction and causes the release of acetylcholine

Question 70

Which of the following motor units would allow for greater muscular control?

A) a motor unit made up of a motor neuron and five muscle fibers.
B) a motor unit made up of a motor neuron and ten muscle fibers.
C) a motor unit made up of a motor neuron and twenty muscle fibers.
D) a motor unit made up of a motor neuron and one hundred muscle fibers.
E) a motor unit made up of a motor neuron and one thousand muscle fibers.

Question 71

Most types of nerve gas exert their effect by inactivating acetylcholinesterase. One of the antidotes for nerve gas is atropine, which is also a poison. Although it may seem strange to have one poison counteract the effects of another poison, which of the following suggestions might be accurate for the effect that atropine has on the neuromuscular junction?

A) Atropine increases the production of acetylcholine in the synaptic vesicles.
B) Atropine increases the release of acetylcholine across the synaptic cleft.
C) Atropine increases the number of receptor sites for acetylcholine on the muscle cell membrane.
D) Atropine attaches to receptor sites for acetylcholine on the muscle cell membrane.
E) Atropine increases both the release of acetylcholine and the number of available receptor sites.

Question 72

The _______ phase is the time between the application of a stimulus and the beginning of a contraction.

A) lag
B) relaxation
C) contraction
D) refractory

Question 73

The constant tension produced by muscles for long periods of time is ___________.

A) potential energy
B) muscle tone
C) myofibril energy
D) muscle energy