Deck 8: Movement

Question 1

 A muscle relaxes after contracting when

A) calcium is taken up by internal organelles.
B) internal ACh is broken apart by acetylcholinesterase (AChE).
C) troponin is taken up by internal organelles.
D) myosin and actin begin to interact.

Answer 1

calcium is taken up by internal organelles.

Question 2

 One major difference between striated and smooth muscles is that

A) smooth muscles move the voluntary system and striated muscles move automatic systems.
B) striated muscles are responsible for fast twitch and smooth muscles are responsible for slow twitch.
C) striated muscles move mostly voluntary systems while smooth muscles move involuntary, automatic systems.
D) smooth muscles are made up of myofibrils and striated muscles are made up of only sarcomeres.

Answer 2

striated muscles move mostly voluntary systems while smooth muscles move involuntary, automatic systems.

Question 3

 ________ is a protein that makes up the thin filaments of myofibril.

A) Pectin
B) Myosin
C) Actin
D) Sarcomere

Answer 3

Actin

Question 4

 The separation of actin molecules from myosin molecules requires

A) calcium.
B) sodium.
C) ACh.
D) energy.

Question 5

 What is the function of striated muscles?

A) control blood pressure and move the eyes and lung
B) move nutrients through the digestive tract and move bones
C) control the heart and skeletal muscles
D) control blood pressure and move the heart

Question 6

 After Juliet has eaten a meal, her _____ muscles will move the nutrients and waste through her digestive system.

A) smooth
B) cardiac
C) striated
D) both smooth and striated

Question 7

 Muscle fibers contract when Z lines move _________ and the sarcomeres _________.

A) farther apart; stretch
B) farther apart; shorten
C) closer together; stretch
D) closer together; shorten

Question 8

 Single segments of a myofibril are called

A) sarcomeres.
B) twitches.
C) Z lines.
D) troponins.

Question 9

 The arrival of an action potential in a muscle fiber causes

A) calcium to enter the muscle fiber.
B) calcium to be released by internal organelles.
C) ACh to enter the muscle fiber.
D) ACh to be released by internal organelles.

Question 10

 What causes muscles to twitch?

A) depolarization of the muscle fiber produced by an influx of sodium ions
B) depolarization of the muscle fiber produced by an influx of potassium ions
C) hyperpolarization of the muscle fiber produced by an influx of calcium ions
D) hyperpolarization of the muscle fiber produced by an outflow of potassium ions

Question 11

 Slow-twitch muscle fibers are to _______ as fast-twitch muscle fibers are to _______.

A) Ia; Ib
B) IIa; Ia
C) I; IIa and IIb
D) IIb; IIa

Question 12

 The long strands of protein running the length of a muscle fiber are called

A) sarcomeres.
B) myofibrils.
C) Z lines.
D) troponins.

Question 13

  Keino has been studying for a quiz so he is confident that the structure that is labeled #3 is the

A) myofibril.
B) Z line.
C) sarcomere.
D) myosin.

Question 14

 The lungs are moved by _________ muscle

A) smooth
B) cardiac
C) striated
D) both smooth and striated

Question 15

 The coroner of a small town was sent a body to examine. The coroner explained to her technician that the body had rigor mortis because of

A) a drop in ACh levels after death.
B) a lack of energy needed to separate actin and myosin molecules.
C) an increase in intracellular calcium concentrations after death.
D) the breakdown of troponin molecules after death.

Question 16

 Mellie is studying for a quiz and writes in her notes that a Z line is

A) a segment of myofibril.
B) a measurement used to determine muscle mass.
C) the boundary of a sarcomere.
D) a reflex pathway in the nervous system.

Question 17

 Professor Van Zile tells his class that, in a resting muscle fiber, _________ binding sites are covered by a protein called _________.

A) actin; tropomyosin
B) actin; troponin
C) myosin; tropomyosin
D) myosin; troponin

Question 18

 Action potentials in muscle fibers

A) do not occur.
B) spread out in two directions on either side of a receptor site.
C) travel in only one direction, from one end of a muscle fiber to the other.
D) lead to multiple twitches in that fiber.

Question 19

 Professor Ammon is giving a class demonstration about how muscle fibers have receptors for ______ that open _____ channels.

A) acetylcholine (ACh); sodium
B) ACh; potassium
C) glutamate; sodium
D) glutamate; potassium

Question 20

 Slow-twitch fibers and fast-twitch fibers are both a type of

A) myosin filament.
B) actin filament.
C) myofibril.
D) sarcomere.

Question 21

 Farhad is in a graduate program conducted by NASA. He is interested in studying the effects of low/no gravity on muscle mass since previous research has shown that time spent in low gravity _____.

A) does not affect muscle mass in men but does in women.
B) increases muscle mass.
C) decreases muscle mass.
D) converts fast-twitch muscles to slow-twitch muscles.

Question 22

 In adult humans, alpha motor neurons are

A) small and unmyelinated.
B) small and myelinated.
C) large and unmyelinated.
D) large and myelinated.

Question 23

 Humberto runs marathons. While running, he relies on his ______ muscles that are ______.

A) fast-twitch; aerobic
B) fast-twitch; anaerobic
C) slow-twitch; aerobic
D) slow-twitch; anaerobic

Question 24

 Fast-twitch fibers contract up to _________ times more rapidly than slow-twitch fibers.

A) 2
B) 5
C) 10
D) 12

Question 25

 Age-related changes in muscle function

A) are related to genetics and cannot be changed.
B) can be completely stopped through exercise.
C) cannot be stopped, but people can compensate somewhat for these changes by exercising.
D) cannot be stopped, but people can compensate somewhat for these changes by eating carefully.

Question 26

 Motor neurons are

A) evenly distributed throughout the gray matter of the spinal cord.
B) evenly distributed throughout the white matter of the spinal cord.
C) more numerous in spinal segments serving the middle torso.
D) more numerous in spinal segments serving the arms and legs.

Question 27

 Spinal motor neurons responsible for contracting muscles are known as _________ motor neurons.

A) alpha
B) beta
C) gamma
D) theta

Question 28

 The muscles of the arms and shoulders contain

A) approximately equal amounts of fast- and slow-twitch fibers, making them well suited for both endurance and explosive movements.
B) higher proportions of slow-twitch fibers, making them better suited for endurance than for explosive movements.
C) higher proportions of fast-twitch fibers, making them better suited for explosive movements than for endurance movements.
D) higher proportions of fast-twitch fibers, making them better suited for endurance than for explosive movements.

Question 29

 What happens to the rate of firing in motor neurons as we age?

A) No changes occur.
B) Firing rates decrease, leading to slower and weaker muscle responses.
C) Firing rates increase, leading to uncomfortable cramping.
D) Firing rates decrease, but muscle fibers are able to compensate for these changes.

Question 30

 The proportion of fast- and slow-twitch fibers found in an individual's quadriceps muscle is primarily determined by the

A) individual's diet.
B) number of hours the individual spends each week engaged in anaerobic activity, like weightlifting.
C) the type of ACTN3 genes that person has.
D) number of hours the individual spends each week engaged in aerobic activity, like running or cycling.

Question 31

 Brandon loves to spend many hours per week in the weight room, and he is quite muscular. Brandon's muscles have enlarged as a result of

A) scar tissue.
B) the breakdown of sarcomeres and Z lines.
C) the production of more troponin.
D) the production of more actin and myosin filaments.

Question 32

 An athlete with likely potential in Olympic weightlifting would probably have _________ in the quadriceps muscle.

A) about the same number of fast- and slow-twitch fibers
B) more fast- than slow-twitch fibers
C) more slow- than fast-twitch fibers
D) only fast-twitch muscles

Question 33

 Which of the following areas of the spinal cord show enlargement of the ventral horns due to large numbers of motor neurons?

A) C1-C2 and T2-T12
B) C1-C2 and L1-S3
C) C3-T1 and T2-T12
D) C3-T1 and L1-S3

Question 34

 Compared to when he was a young man, Chris's muscles ______ now that he has grown old.

A) contain fibers that are more angular than round
B) show a more even distribution of slow- and fast-twitch fibers
C) are more likely to be hybrids of fast- and slow-twitch fibers
D) are more likely to be made up of slow-twitch fibers

Question 35

 Elaine has suffered a spinal cord injury. It is likely that she has had a loss of ____ muscle fibers.

A) slow-twitch
B) slow-twitch and fast-twitch
C) fast-twitch
D) autonomic

Question 36

 Alpha motor neurons form connections with muscle fibers at the

A) muscle spindle.
B) antagonistic joint.
C) motor unit.
D) neuromuscular junction.

Question 37

 Muscles dominated by slow-twitch fibers appear _________ due to the presence of _________.

A) white; calcium
B) white; myoglobin
C) red; calcium
D) red; myoglobin

Question 38

 When an Olympic weightlifter uses explosive strength to lift a personal best, the _________ fibers in her legs are probably the most active, but the marathon runner relies on her _________ fibers.

A) slow-twitch; fast-twitch
B) fast-twitch; slow-twitch
C) Type I; Type III
D) Type III; Type II

Question 39

 Observations of the muscle fibers of people who have experienced spinal cord damage suggest that neural input is especially important to the maintenance of

A) fast-twitch fibers.
B) slow-twitch fibers.
C) both fast- and slow-twitch fibers.
D) neither fast- nor slow-twitch fibers.

Question 40

 Age-related loss in muscle mass appears to begin around the age of _________ years.

A) 25
B) 30
C) 75
D) 90

Question 41

 Pam is studying for a quiz on the muscular system. She writes in her notes that extrafusal muscle fibers

A) are found inside each muscle spindle.
B) are responsible for muscle contractions.
C) provide feedback regarding muscle contractions in the arms and legs.
D) are located at the junction between a muscle and tendon.

Question 42

 Which of the following muscle spindle fibers provides information about a muscle's velocity of change?

A) dynamic nuclear bag fibers
B) nuclear chain fibers
C) static nuclear bag fibers
D) dynamic nuclear chain fibers

Question 43

 Professor Berger is giving a lecture about the motor systems in the body. She tells the class that Ia sensory fibers will become active in response to

A) contraction of muscle fibers.
B) input from gamma motor neurons.
C) stretching of muscle fibers.
D) input from Ib fibers.

Question 44

 Compared with other sensory neurons, such as those that serve mechanoreceptors, Ia sensory fibers are

A) far less commonly found in the human nervous system.
B) less likely to be myelinated in the human nervous system.
C) very large and very fast.
D) very small and slow.

Question 45

 Intrafusal fibers receive input from

A) alpha motor neurons.
B) gamma motor neurons.
C) Ia sensory fibers.
D) C fibers.

Question 46

 Where should we look to find Ia sensory fibers?

A) at the neuromuscular junction where they are forming synapses with muscle fibers
B) wrapped around the middle sections of muscle spindle fibers
C) in the junctions between muscles and tendons
D) in joints and in the skin

Question 47

 Professor Gallo tells his class that variations in the firing rate of motor neurons so that they meet the need for a certain amount of contraction is called

A) the motor neuron pool.
B) the rate code.
C) tetanus.
D) recruitment.

Question 48

 Professor Williams is giving a lecture about the motor systems in the body. He tells the class that we need muscle spindles to

A) provide feedback regarding muscle contraction.
B) provide feedback regarding position of joints.
C) provide feedback regarding muscle length.
D) contract muscles.

Question 49

 Without input from the gamma motor neurons,

A) extrafusal muscle fibers would be unable to contract.
B) intrafusal muscle fibers would not be able to relax.
C) extrafusal fibers would go limp whenever intrafusal fibers contracted.
D) intrafusal fibers would go limp whenever extrafusal fibers contracted.

Question 50

 Intrafusal muscle fibers

A) are found in muscle spindles.
B) are responsible for muscle contractions.
C) provide feedback regarding muscle contractions.
D) are located at the junction between a muscle and tendon.

Question 51

 Which of the following sequences describes the typical order in which motor units are recruited?

A) Type IIb, Type IIa, Type I
B) Type IIb, Type I, Type IIa
C) Type I, Type IIa, Type IIb
D) Type I, Type IIb, Type IIa

Question 52

 A single alpha motor neuron and the muscle fibers it innervates are known as a(n)

A) motor junction.
B) motor unit.
C) intrafusal unit.
D) antagonistic unit.

Question 53

 Alla is studying for a quiz on the motor systems in the body. She writes in her notes that all of the motor neurons that innervate a single muscle are collectively called a

A) motor neuron pool.
B) motor unit.
C) neuromuscular junction.
D) muscle spindle.

Question 54

 Alpha motor neurons receive input from

A) neurons in muscle spindles only.
B) neurons in muscle spindles and Golgi tendon organs.
C) spinal interneurons and neurons of the brainstem and motor cortex.
D) neurons in muscle spindles and Golgi tendon organs, neurons of the brainstem and motor cortex, and spinal interneurons.

Question 55

 Recruitment proceeds in a way that ensures that the

A) least amount of energy and force possible will be used to do a job.
B) greatest amount of energy and force possible will be used to do a job.
C) fastest fibers will be recruited first to produce optimum reaction time.
D) fibers with the greatest oxygen requirements will be used only when absolutely necessary for survival.

Question 56

 A single motor unit usually contains a motor neuron and

A) one muscle fiber.
B) both fast- and slow-twitch fibers.
C) either fast-twitch or slow-twitch fibers but not a mixture of the two types.
D) a muscle spindle.

Question 57

 Temporal summation may occur at the neuromuscular junction because

A) action potentials last longer than muscle contractions.
B) muscle contractions last longer than action potentials.
C) many motor neurons form synapses at a single neuromuscular junction.
D) ACh is broken down slowly in the synaptic gap.

Question 58

 Isaac observed a sample of motor units in which single neurons innervated fibers of the same type. This led Isaac to conclude that

A) neural input probably determines the identity of muscle fibers as slow- or fast-twitch.
B) the organism that supplied the samples had probably suffered a spinal cord injury.
C) the organism that supplied the samples was very old.
D) his sample was not representative, and he needed to obtain more samples before reaching a conclusion.

Question 59

 Samantha is about to hand Megan a notebook that contains her biological psychology notes. Which of the following correctly describes how Megan's muscles will react to the heavy notebook?

A) The weight of the notebook will cause Megan's arm muscles to contract. This information will be sensed by mechanoreceptors around her joints and sent to her spinal cord via Ib fibers. The Ib fibers will excite gamma motor neurons, which will cause her arm to contract further to adjust to the heavier weight of the book.
B) The weight of the notebook will cause Megan's arm muscles to stretch. This information will be sensed by her spindles and sent to her spinal cord by gamma motor neurons. The gamma motor neurons will inhibit the alpha motor neurons, causing her arm muscles to relax enough that she won't drop the book.
C) The weight of the notebook will cause Megan's arm muscles to contract. This information will be sensed by her Golgi tendon organs and sent to her spinal cord by Ib sensory fibers. The Ib sensory fibers will excite alpha motor neurons that will cause her arm muscles to stretch enough that she won't drop the book.
D) The weight of the notebook will cause Megan's arm muscles to stretch. This information will be sensed by her spindles and sent to her spinal cord by Ia sensory fibers. The Ia sensory fibers will excite alpha motor neurons that will cause her arm muscles to contract enough that she won't drop the book.

Question 60

 Motor units that include Type IIb fibers

A) usually include Type IIa fibers as well.
B) produce about 100 times the force as units that include Type I fibers.
C) produce about one-third of the force produced by units that include Type IIa fibers.
D) are rarely found in humans.

Question 61

  Kadeshia has been studying for a quiz and knows that the structure labeled #2 in the picture is the

A) extrafusal fiber.
B) Ia sensory fiber.
C) gamma motor fiber.
D) intrafusal fiber.

Question 62

 Feedback regarding joint position and movement is provided by

A) muscle spindles.
B) mechanoreceptors.
C) Golgi tendon organs.
D) free nerve endings.

Question 63

 Input from Ib sensory fibers

A) inhibits the activity of alpha motor neurons.
B) activates alpha motor neurons.
C) contracts muscle spindles.
D) contracts muscles.

Question 64

 As you bend your arm up to take a drink, the ________ muscles are active, and when you extend your arm to put the glass down, the ________ muscles are active.

A) striated; smooth
B) flexor; extensor
C) extensor; flexor
D) Type II; Type I

Question 65

 An antagonistic pair of muscles is made up of

A) two extensor muscles at the same joint.
B) two flexor muscles at the same joint.
C) an extensor muscle and a flexor muscle at the same joint.
D) two complex muscles that allow joints like hips and elbows to move in many directions.

Question 66

 The Babinski sign occurs when

A) stroking the sole of the foot causes the toes to spread and the big toe to point upward.
B) stroking the sole of the foot causes the toes to curl and then separate.
C) tapping the knee with a small hammer causes the foot to kick.
D) both extensors and flexors at a joint contract simultaneously in violation of reciprocal inhibition.

Question 67

 Yesterday morning, Naomi accidentally touched a hot part of her toaster. She avoided major injury by quickly removing her hand thanks to

A) reciprocal inhibition.
B) a monosynaptic reflex.
C) an extensor reflex.
D) a flexor reflex.

Question 68

 Elizabeth's grandmother recently underwent a hip replacement operation. Because she took this course, Elizabeth is able to tell her grandmother that she

A) will need to be very careful, because the removal of her joint receptors means that she will not know the position of her hip without looking.
B) will have to relearn how to walk, as the operation removes joint receptors responsible for managing muscle stretch.
C) will still know the position of her hip without looking, even though her operation will remove all of her joint receptors.
D) should prepare to deal with phantom pain from the joint receptors that have been removed.

Question 69

 Professor Hinson tells her class that they need to make sure they know that Golgi tendon organs are innervated by

A) Ia sensory fibers.
B) alpha motor neurons.
C) IIa sensory fibers.
D) Ib sensory fibers.

Question 70

 Which of the following statements about muscle movement is true?

A) The only thing that muscles can do is contract.
B) A single muscle can bend a joint by contracting and straighten it by relaxing.
C) Smooth muscles cause movement by contracting, while striated muscles cause movement by contracting and relaxing.
D) Striated muscles cause movement by contracting, but smooth muscles cause movement by contracting and relaxing.

Question 71

 If Alishia wanted to bend a joint, she would need

A) relaxation of extensors and flexors.
B) contraction of extensors and flexors.
C) relaxation of extensors and contraction of flexors.
D) contraction of extensors and relaxation of flexors.

Question 72

 Ventromedial pathways provide

A) automatic control of the hands, feet, and parts of limbs farther from the body.
B) automatic control of the neck, torso, and parts of limbs close to the body.
C) voluntary control of the hands, feet, and the medial sections of limbs.
D) voluntary control of the neck and torso.

Question 73

 The patellar tendon or "knee jerk" reflex is an example of a _________ reflex.

A) withdrawal
B) flexion
C) monosynaptic
D) polysynaptic

Question 74

 Rey was being evaluated for a possible spinal cord injury during a college football game. The team physician stroked the sole of Rey's foot, and his toes curled. This observation suggests that

A) Rey has a serious spinal cord injury that might affect his future mobility.
B) Rey has a mild spinal cord injury, and with proper treatment, he should recover completely.
C) Rey does not appear to have damaged his spinal cord, although this should be confirmed by further testing.
D) Rey's spinal cord is probably all right, but it appears that he has sustained damage to his foot or ankle.

Question 75

 The lateral pathway originates in the _________ and controls _________ movements.

A) cerebral cortex; voluntary
B) cerebral cortex; automatic
C) brainstem; voluntary
D) brainstem; automatic

Question 76

 Golgi tendon organs provide feedback about

A) muscle stretch.
B) force.
C) position.
D) movement.

Question 77

 Professor Grist tells his class that the Babinski sign is considered to be

A) normal in adults but not in children.
B) normal in children but not adults.
C) normal in children and teenagers until after puberty.
D) abnormal in both adults and children.

Question 78

 If Trey wanted to straighten a joint, he would need his muscles known as

A) extensors.
B) flexors.
C) antagonists.
D) relaxers.

Question 79

 Reciprocal inhibition is a simple type of _________ reflex.

A) monosynaptic
B) polysynaptic
C) flexion
D) withdrawal

Question 80

 The preventing of one member of an antagonist pair of muscles whenever its partner is active is known as

A) a monosynaptic reflex.
B) a withdrawal reflex.
C) a flexion reflex.
D) reciprocal inhibition.