Deck 7: Muscular System

Question 1

A _________ is a single muscle cell.

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

Answer 1

C

Question 2

The ____________ consists of only actin myofilaments.

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

Answer 2

B

Question 3

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 3

A

Question 4

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 5

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 6

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

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

Question 7

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 8

Which of the following areas of the sarcomere disappear when the sarcomere is completely contracted?

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

Question 9

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 10

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 11

Muscle myofibrils

A)contain actin and myosin myofilaments.
B)extend from one end of the muscle fiber to the other.
C)contain sarcomeres joined end to end.
D)have all of these properties.
E)contain actin and myosin myofilaments and extend from one end of the muscle fiber to the other.

Question 12

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 the above are true of muscle fibers

Question 13

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 14

The __________ is attached to bones via tendons.

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

Question 15

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 16

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 17

All of the following are functions of muscle EXCEPT:

A)body movement
B)production of red blood cells
C)constriction of organs and vessels
D)maintenance of posture
E)production of body heat

Question 18

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.

Question 19

Connective tissue that surrounds the fasciculi is called

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

Question 20

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 21

The resting membrane potential

A)occurs when the outside of the cell membrane is negatively charged.
B)is reversed in sign when sodium ions rush out of the cell.
C)will be changed if the membrane permeability to one or more ions is selectively altered.
D)is reestablished by depolarization after an action potential.
E)only occurs when the cytosol has a net negative charge.

Question 22

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 23

The letter A in this figure represents the

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

Question 24

Anaerobic respiration

A)is used by all cells during sustained periods of exercise.
B)produces the most ATP's for each glucose molecule broken down.
C)produces lactic acid within the muscle.
D)produces an oxygen deficit.
E)produces lactic acid within the muscle and produces an oxygen deficit.

Question 25

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 26

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 27

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 28

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 29

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 30

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 the above are true of aerobic respiration

Question 31

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 32

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 33

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 34

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 35

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 36

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 37

The letter B in this figure represents

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

Question 38

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 39

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 40

Mary Thon,a long-distance runner,asks her coach why it is so difficult to have a "finishing kick" (sprinting the last hundred yards to the finish line).Her coach should reply:

A)Sprinting requires large amounts of oxygen,and she doesn't have much available at that point.
B)There is no physiological reason why the finishing kick should be difficult.
C)Sprinting requires fatty acids,which are likely to be gone at that point.
D)Anaerobic activities like sprinting are limited by available glucose and rate of buildup of lactic acid.
E)She has already built up an oxygen deficit from too much aerobic exercise.

Question 41

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 42

The major abductor of the upper limb is the

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

Question 43

The anterior forearm muscles

A)extend the wrist and fingers.
B)are called intrinsic hand muscles.
C)flex the wrist and fingers.
D)supinate the forearm.
E)perform both flexion and supination at the wrist.

Question 44

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 45

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 46

"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 47

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 48

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 49

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 50

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 51

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 52

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 the above features.

Question 53

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 the above are true

Question 54

Muscles of mastication include

A)the masseter.
B)the hyoid muscles.
C)the pharyngeal constrictors.
D)the temporalis.
E)both the masseter and the temporalis.

Question 55

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 56

A muscle located on either side of the linea alba,which flexes the waist and is crossed by tendinous intersections is the

A)transversus abdominis.
B)external intercostal.
C)external abdominal oblique.
D)rectus abdominis.
E)erector spinae.

Question 57

Which of the following muscles are involved in "puckering up" to kiss someone?

A)orbicularis oris
B)buccinator
C)zygomaticus major
D)Both orbicularis oris and buccinator are required to "pucker up."
E)Both buccinator and zygomaticus major are required to "pucker up."

Question 58

Which of the following statements is FALSE?

A)Smooth muscle does not have actin & myosin.
B)Smooth muscle is not striated.
C)Smooth muscle cells have gap junctions.
D)One function of smooth muscle is to constrict blood vessels.
E)Smooth muscle can contract either in response to signals from the nervous system or on its own (autorhythmicity).

Question 59

Musk L.Bound,a world-class weight lifter,had some muscle tissue from his gastrocnemius muscle analyzed microscopically.Which of the following results would be most likely?

A)a high percentage of slow-twitch fibers,large muscle mass
B)a high percentage of fast-twitch fibers,large muscle mass
C)a high percentage of slow-twitch fibers,greatly increased vascularity
D)a high percentage of fast-twitch fibers,greatly increased vascularity
E)a high percentage of slow-twitch fibers,high myoglobin content

Question 60

An anterior thigh muscle that extends the leg is the

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

Question 61

Muscles that work together to cause movement are called

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

Question 62

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 63

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 64

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 65

Which of the following conditions is INCORRECTLY paired?

A)fibromyalgia - chronic widespread pain in muscles and muscle-tendon junctions
B)duchenne's Muscular Dystrophy - results from the faulty production of dystrophin
C)tendinitis - inflammation of a tendon or its attachment point
D)hypertrophy - a decrease in myofilaments within the muscle fibers
E)cramps - spastic contractions of muscle usually the result of an irritation

Question 66

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 67

The ___________ is the most stationary end of a muscle.

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

Question 68

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 69

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 70

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

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

Question 71

Botulinus toxin causes paralysis by preventing the exocytotic release of acetylcholine from the synaptic vesicles.Which of the following events would still occur in a tissue treated with this toxin?

A)Calcium ion channels in the pre-synaptic membrane open allowing Ca⁺⁺ to enter the neuron.
B)Acetylcholine is released into the pre-synaptic cleft.
C)A post-synaptic action potential is generated in the muscle fiber.
D)Sodium ion channels in the post-synaptic membrane open.
E)The muscle fiber contracts.

Question 72

To treat some of the symptoms of Myasthenia gravis,physicians sometimes prescribe the anticholinesterase drug neostigmine.Why does this drug help with the symptoms of muscle weakness and fatigue?

A)The drug inhibits the production of the antibodies which the patient's immune system forms against ACh receptors.It thereby prevents the breakdown of ACh receptors so the muscle cells receive the normal contraction stimuli.
B)The drug increases the amount of acetylcholine released by the neuron,thereby increasing the chance that the few ACh remaining receptors on the muscle fiber membranes will bind ACh and receive the signal to contract.
C)The drug inhibits the activity of acetylcholinesterase,which prevents the breakdown of ACh.Consequently,ACh levels in the synapse remain elevated,thereby increasing the stimulation of the reduced number of functional ACh receptors.
D)The drug acts as an AP and signals the release of ACh.Consequently,ACh levels in the synapse remain elevated,thereby increasing the stimulation of the reduced number of functional ACh receptors.
E)The drug increases the activity of acetylcholinesterase.ACh is then broken down more quickly,thereby allowing a quicker signal cycle.

Question 73

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 74

The muscle that works in opposition to another muscle is the

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

Question 75

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 76

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 77

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 78

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 79

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 80

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 the above are true.