Deck 48: Musculoskeletal Systems

Question 1

The long bones of our arms and legs are strong and can resist both compressional and bending forces because

A) they are solid rods of compact bone.
B) their extracellular matrix contains crystals of calcium carbonate.
C) their extracellular matrix consists mostly of collagen and polysaccharides.
D) they have a high density of osteoclasts.
E) they consist of lightweight cancellous bone with an internal meshwork of supporting elements.

Answer 1

A

Question 2

Use the following to answer questions:
Match the correct muscle type from the list below with each description that follows. Each term may be used more than once.

-Which muscle type has a pacemaking function?

A)Smooth
B)Cardiac
C)Skeletal

Answer 2

Cardiac

Question 3

A flea manages to jump up to 200 times its body length by

A) using very powerful muscles.
B) compressing an elastic material in its legs.
C) compressing water, which jets out of small holes in its carapace.
D) using vestigial wings to assist its muscles.
E) taking advantage of the shape of its carapace and gliding.

Answer 3

B

Question 4

A frog can jump _______ times its body length, a human can jump _______ times his or her body length, and a flea can jump _______ times its body length.

A) 20; 5; 200
B) 6.5; 7.4; 1.2
C) 5; 20; 200
D) 200; 5; 20
E) 7.4; 6.5; 1.2

Question 5

Use the following to answer questions:
Match the correct muscle type from the list below with each description that follows. Each term may be used more than once.

-Which muscle type has the least regular arrangements of actin and myosin?

A)Smooth
B)Cardiac
C)Skeletal

Question 6

Which statement about skeletal muscle contraction is not true?

A) A single action potential at the neuromuscular junction is sufficient to cause a muscle to twitch.
B) Once maximum muscle tension is achieved, no ATP is required to maintain that level of tension.
C) An action potential in the muscle cell activates contraction by releasing Ca²⁺ into the sarcoplasm.
D) Summation of twitches leads to a graded increase in the tension that can be generated by a single muscle fiber.
E) The tension generated by a muscle can be varied by controlling how many of its motor units are active.

Question 7

Use the following to answer questions:
Match the correct muscle type from the list below with each description that follows. Each term may be used more than once.

-Which muscle type uses calcium to trigger actin-myosin interactions for movement?

A)Smooth
B)Cardiac
C)Skeletal

Question 8

Unlike humans, kangaroos can increase their movement speed without an increase in their metabolic rate because

A) their diet is more energy-rich than ours is.
B) they have more mitochondria per cell than we do.
C) the recoil in their elastic tendons helps power each jump.
D) they convert starch directly to ATP without first hydrolyzing it to glucose.
E) they alternate which foot they use each time they jump.

Question 9

If we compare the jaw and knee joints as lever systems,

A) the jaw joint can apply greater compressional forces.
B) their ratios of power arm to load arm are about the same.
C) the knee joint has greater rotational abilities.
D) the knee joint has a greater ratio of power arm to load arm.
E) only the jaw is a hinged joint.

Question 10

Smooth muscle differs from both cardiac and skeletal muscle in that

A) it can act as a pacemaker for rhythmic contractions.
B) contractions of smooth muscle are not due to interactions between neighboring microfilaments.
C) neighboring cells are electrically connected by gap junctions.
D) neighboring cells are tightly coupled by intercalated discs.
E) the membranes of smooth muscle cells are depolarized by stretching.

Question 11

Use the following to answer questions:
Match the correct muscle type from the list below with each description that follows. Each term may be used more than once.

-Which muscle type has gap junctions?

A)Smooth
B)Cardiac
C)Skeletal

Question 12

Insects can beat their wings at exceptionally high frequencies because

A) their wing muscles have mostly fast-twitch fibers.
B) their motor neurons can fire action potentials at a very high frequency.
C) their wings have exoskeletal supports.
D) their wing muscles have extensive sarcoplasmic reticulum that cycles Ca²⁺ very fast.
E) their wing muscles can generate a rapid oscillation of contraction asynchronous with motor neuron firing.

Question 13

Fifteen minutes into a 10k run, what is the major energy source of the leg muscles?

A) Preformed ATP
B) Glycolysis
C) Oxidative metabolism
D) Pyruvate and lactate
E) High-protein drink consumed right before the race

Question 14

Fast-twitch fibers differ from slow-twitch fibers in that

A) they are more common in the leg muscles of champion sprinters than marathon runners.
B) they have more mitochondria.
C) they fatigue less rapidly.
D) their abundance is more a product of training than of genetics.
E) they are more common in postural muscles than in finger muscles.

Question 15

The striated appearance of skeletal muscle is due to the

A) dark color of myosin.
B) multiple nuclei per fiber.
C) regular arrangement of filaments.
D) dense array of microtubules.
E) dense packing of ATP molecules.

Question 16

The role of Ca²⁺ in the control of muscle contraction is to

A) cause depolarization of the T tubule system.
B) change the conformation of troponin, thus exposing myosin-binding sites.
C) change the conformation of myosin heads, thus causing microfilaments to slide past each other.
D) bind to tropomyosin and break actin-myosin cross-bridges.
E) block the ATP-binding site on myosin heads, enabling muscles to relax.

Question 17

Use the following to answer questions:
Match the correct muscle type from the list below with each description that follows. Each term may be used more than once.

-Which muscle type is multinucleated?

A)Smooth
B)Cardiac
C)Skeletal

Question 18

An individual sarcomere unit consists of

A) a stack of actin fibers.
B) a stack of myosin units.
C) overlapping actin and membrane.
D) overlapping myosin and membrane.
E) overlapping actin and myosin.

Question 19

Which statement about skeletons is true?

A) They can consist of mostly cartilage.
B) Hydrostatic skeletons cannot be used for locomotion.
C) An advantage of exoskeletons is that they can continue to grow throughout the life of the animal.
D) External skeletons must remain flexible, so they never include calcium carbonate crystals, as bones do.
E) Internal skeletons consist of four different types of bone: compact, cancellous, membranous, and Haversian.

Question 20

Which statement about the structure of skeletal muscle is true?

A) The light bands of the sarcomere are the regions where actin and myosin filaments overlap.
B) When a muscle contracts, the A bands of the sarcomere lengthen.
C) The myosin filaments are anchored in the Z lines.
D) When a muscle contracts, the H zone of the sarcomere shortens.
E) The sarcoplasm of the muscle cell is contained within the sarcoplasmic reticulum.

Question 21

_______ complexes with calcium and acts as a second messenger in smooth muscle cells.

A) Myosin
B) Actin
C) Troponin
D) cAMP
E) Calmodulin

Question 22

Which of the following represents the one similarity between fast- and slow-twitch muscle fibers?

A) Number of mitochondria
B) Amount of myoglobin
C) Amount of glycogen and fat
D) Number of neuromuscular junctions
E) Number of blood vessels

Question 23

Which of the following events does not occur during muscle contraction?

A) The distance between Z lines increases.
B) The sarcomere shortens.
C) The H zone is reduced.
D) The I band is reduced.
E) The area of actin and myosin overlap increases.

Question 24

Starting with the arrival of an action potential at the neuromuscular junction, which of the following is the correct order of events?

A) Calcium is released from the sarcoplasmic reticulum, an action potential travels down the T tubules, depolarization spreads through the T tubule, and myosin binds actin.
B) An action potential travels down the T tubules, depolarization spreads through the T tubule, calcium is released from the sarcoplasmic reticulum, and myosin binds actin.
C) An action potential travels down the T tubules, depolarization spreads through the T tubule, calcium is taken up by the sarcoplasmic reticulum, and myosin binds actin.
D) An action potential travels down the T tubules, depolarization spreads through the T tubule, ATP binds to myosin, and myosin binds actin.
E) A T tubule is depolarized, calcium is released from the sarcoplasmic reticulum, an action potential is created in the muscle cell, and myosin binds actin.

Question 25

Muscle tone is the condition in which

A) different muscles are taking responsibility for maintaining posture.
B) the muscle has generated maximum tension.
C) the muscle will eventually exhaust its supply of ATP.
D) a small but changing number of motor units is active.
E) the maximum number of action potentials is being received by the muscle.

Question 26

Which of the following is a feature of cardiac muscle that helps the heart withstand high pressures without tearing?

A) Branching and intertwined fibers
B) Fibers arranged in parallel
C) A single nucleus possessed by each fiber
D) Gap junctions between fibers
E) The pacemaking functions of some fibers

Question 27

Which of the following statements about the molecular arrangement of actin and myosin in myofibrils is false?

A) A thin filament consists of actin and tropomyosin.
B) Two chains of actin monomers are twisted into a helix.
C) Two strands of tropomyosin lie in the grooves of the actin.
D) Troponin forms the head of the myosin molecule.
E) The myosin heads have ATPase activity and interact with the actin.

Question 28

How do actin and myosin molecules interact?

A) Globular myosin heads bind to actin filaments.
B) Globular actin heads bind to myosin filaments.
C) Other proteins connect the two.
D) Myosin filaments bend to connect to actin.
E) Actin filaments bend to connect to myosin.

Question 29

Fast-twitch skeletal muscle fibers, called white muscle, are characterized by

A) a high concentration of myoglobin.
B) abundant mitochondria.
C) the rapid development of high tension.
D) the ability to sustain activity for a long time.
E) a higher oxygen requirement than that of slow-twitch fibers.

Question 30

Vertebrate skeletal muscles are excitable cells because they

A) can be stimulated by ATP.
B) can be stimulated by an electric charge.
C) can secrete neurotransmitter.
D) possess voltage-gated sodium channels.
E) can attain a high level of activity.

Question 31

When animals die, muscles stiffen in rigor mortis because

A) muscles cannot contract without ATP.
B) actin and myosin cannot bind without ATP.
C) actin and myosin cannot separate without ATP.
D) ATP is required for synthesis of protein filaments.
E) ATP forms cross-bridges between filaments.

Question 32

The strength or weakness of a muscle contraction depends on the number of motor units activated and the frequency at which they are firing. An increase in either of these two factors allows for graded contractions through the process of

A) transmission.
B) transduction.
C) multiplication.
D) summation.
E) coordination.

Question 33

Which of the following statements about smooth muscle is false?

A) Smooth muscle is under the control of the autonomic nervous system.
B) Smooth muscle cells are multinucleate.
C) Smooth muscle appears unstriated when viewed with the microscope.
D) Gap junctions are common in smooth muscle.
E) Stretched smooth muscle will contract.

Question 34

How does tropomyosin control muscle contraction?

A) It provides a bridge between actin and myosin.
B) It provides a site where ATP can be utilized.
C) Changes in its position expose actin-myosin binding sites.
D) It transmits electric charge to the filaments.
E) Changes in its shape open membrane channels.

Question 35

What is the role of the sarcoplasmic reticulum in muscle contraction?

A) It stores Ca²⁺ ions for release during contraction.
B) It surrounds and protects the muscle filaments.
C) It provides sites of ATP synthesis.
D) It depolarizes when stimulated by an impulse.
E) It synthesizes actin and myosin filaments.

Question 36

Muscle fibers show a range of responses to different levels of stimulation because

A) each muscle fiber contraction is "all or none."
B) the availability of Ca²⁺ sets an upper limit to the strength of the contraction.
C) a new contraction can occur only after the resting condition is reached.
D) following stimulation, the fiber stays contracted.
E) individual twitches in the same fiber can summate.

Question 37

When troponin binds calcium,

A) it allows tropomyosin to bind actin.
B) ion channels open, and sodium rushes into the muscle cells.
C) it changes conformation, twisting tropomyosin and exposing the actin-myosin binding site.
D) it changes conformation, exposing the ATP binding site and allowing the actin-myosin bond to break.
E) calmodulin binds to calcium and starts a cascade by activating myosin kinase.

Question 38

The resting potential of smooth muscle cells is

A) not likely to fire action potentials.
B) affected by the stretching of the cells.
C) more negative than in most cells.
D) unaffected by nearby potential change.
E) nearly zero.

Question 39

The legs of cross-country skiers and long-distance runners are likely to have

A) almost all slow-twitch fibers.
B) almost all fast-twitch fibers.
C) about the same number of slow-twitch and fast-twitch fibers.
D) more slow-twitch fibers.
E) more fast-twitch fibers.

Question 40

How do muscle fibers shorten during contraction?

A) Individual protein filaments contract.
B) More cross-bridges are formed between filaments.
C) Arrays of filaments overlap each other.
D) Protein filaments coil more tightly.
E) Subunits of protein polymers detach.

Question 41

Which of the following statements about fast-twitch and slow-twitch fibers is false?

A) In skeletal muscle, the most important factor determining the proportion of fast- and slow-twitch fibers is genetic heritage.
B) Aerobic training increases the oxidative capacity of intermediate fibers.
C) A single muscle may contain fast- and slow-twitch fibers.
D) Fast-twitch fibers fatigue slowly.
E) All of the above are true; none is false.

Question 42

Slow-twitch muscles

A) are also called oxidative muscle.
B) are also called red muscle.
C) are well supplied with mitochondria.
D) contain the oxygen-binding protein myoglobin.
E) All of the above

Question 43

Anaerobic exercise such as weight lifting

A) increases strength.
B) can do minor tissue damage.
C) induces the formation of new actin and myosin filaments in existing muscle fibers.
D) produces bigger muscle fibers and hence bigger muscles.
E) All of the above

Question 44

The most important determinant of the proportion of fast- and slow-twitch fibers in skeletal muscle is

A) diet.
B) exercise.
C) genetic heritage.
D) age.
E) None of the above

Question 45

Wild turkeys have breast muscles that are capable of explosively fast flight, but only for short distances. These muscles

A) fuel their rapid flight with high levels of mitochondria.
B) have surprisingly low rates of ATPase activity.
C) are fast-twitch muscles.
D) are slow-twitch muscles.
E) have substantial reserves of glycogen.

Question 46

Which of the following statements about slow-twitch and fast-twitch muscles is true?

A) One is smooth muscle and one is skeletal muscle.
B) They express different genes in their myosin molecules.
C) One occurs only in mammals.
D) They typically have similar numbers of mitochondria per cell.
E) Those with low ATPase activity compensate by quickly recycling their actin-myosin bridges.

Question 47

Salmon returning to spawn in their native stream require extreme endurance for the journey. An examination of the muscles used to perform this activity would show that they

A) have substantial reserves of fuel.
B) have low levels of ATPase activity.
C) are well-supplied with blood vessels.
D) have many mitochondria.
E) All of the above

Question 48

Aerobic exercise such as jogging increases

A) myoglobin.
B) the number of mitochondria in skeletal muscle cells.
C) the enzymes involved in energy utilization.
D) the density of capillaries.
E) All of the above

Question 49

A muscle reaches its maximum force of contraction when it is stretched to _______ percent of its resting length.

A) 100
B) 80
C) 60
D) 40
E) 20

Question 50

Bricklayers periodically need to carry heavy stacks of bricks from their truck to the work site. An examination of the muscles used to perform this work would show that they

A) have substantial reserves of fuel.
B) have low levels of ATPase activity.
C) are well-supplied with blood vessels.
D) have relatively few mitochondria.
E) develop tension quickly.

Question 51

Insect flight muscles can contract up to _______ times per second.

A) 5
B) 50
C) 100
D) 500
E) 1,000

Question 52

Migrating birds often cross the Gulf of Mexico in a single flight, and their flight muscles demand extreme endurance. An examination of the muscles used to perform this activity would show that they

A) have substantial reserves of fuel.
B) have low levels of ATPase activity.
C) are well-supplied with blood vessels.
D) have many mitochondria.
E) All of the above

Question 53

Which of the following limits a muscle's capacity to be shortened?

A) Bones, which eventually impede further contraction.
B) The overlap of actin and myosin, which eventually causes myosin to push against the Z line.
C) The overlap of actin and myosin, which eventually causes actin to push against the Z line.
D) The water component of fiber cell cytoplasm, which is incompressible.
E) All of the above

Question 54

The three systems by which muscles obtain ATP

A) differ in the capacity and rate at which they produce ATP.
B) rely on the large amounts of ATP stored in muscle.
C) produce similar amounts of ATP.
D) rely on reactions within mitochondria.
E) have similar time courses.

Question 55

Shot-putters competing in track and field events need short, intense bursts of energy, but find that they are quickly fatigued by the activity. An examination of the muscles used in this sport would show that they

A) have substantial reserves of fuel.
B) have low levels of ATPase activity.
C) are well-supplied with blood vessels.
D) have relatively few mitochondria.
E) develop tension quickly.

Question 56

Which of the following is not one of the systems that supplies muscles with the ATP needed for contraction?

A) Immediate system
B) Pyruvic system
C) Glycolytic system
D) Oxidative system
E) Both a and d

Question 57

The glycolytic system by which muscles obtain ATP

A) relies on creatine phosphate.
B) is also referred to as the immediate system.
C) is the most efficient means of producing ATP.
D) produces lactic acid.
E) completely metabolizes carbohydrates and fats.

Question 58

If the slow-twitch muscle fiber of a marathon runner, weight lifter, and triathlon competitor (5k run, 1k swim, 10k bike) were compared, which of the following would represent the correct order, from highest to lowest, of the percentage of slow-twitch muscle in their bodies?

A) Triathlete, marathon runner, weight lifter
B) Weight lifter, marathon runner, triathlete
C) Marathon runner, triathlete, weight lifter
D) Triathlete, weight lifter, marathon runner
E) Marathon runner, weight lifter, triathlete

Question 59

The last little bit of a chin-up is usually the most difficult to perform because

A) of the lever properties of the muscle-joint interaction.
B) stretched sarcomeres have less overlap where cross-linking can occur.
C) of psychological fatigue that is a metabolic by-product of the exertion.
D) the necessary switch from fast- to slow-twitch fibers.
E) Both a and b

Question 60

Fast-twitch fibers

A) are also called white muscle.
B) fatigue rapidly.
C) have fewer mitochondria per cell than do slow- twitch fibers.
D) are also glycolytic muscle.
E) All of the above

Question 61

The major disadvantage of the glycolytic system for supplying ATP to muscle fibers is

A) the inefficiency of glycolysis compared to aerobic respiration.
B) the long period of time that is required before it can start supplying ATP.
C) that it leads to the accumulation of lactic acid.
D) Both a and c
E) All of the above

Question 62

Which of the following statements about the growth of long bones is false?

A) Ossification starts at the center of long bones.
B) Elongation occurs at epiphyseal plates.
C) Secondary sites of ossification occur at the ends of long bones.
D) Long bones begin as cartilaginous bones.
E) Long bones form as scaffolding on a connective tissue membrane.

Question 63

Which of the following represents the major difference between strength training and aerobic exercise?

A) Only strength training increases endurance by creating more muscle fibers.
B) Only aerobic exercise increases the size of muscle fibers.
C) Only strength training increases the production of myoglobin.
D) Only aerobic exercise increases the oxidative capacity of muscles.
E) Only strength training increases the density of capillaries delivering oxygen to the muscles.

Question 64

Satellite cells

A) communicate a muscle fiber's need for more O₂.
B) lie in a ring around the muscle fibers, absorbing their metabolic waste.
C) produce new muscle fibers.
D) move through the fibers, providing ATP where its most needed.
E) are phagocytic, watching for and then attacking pathogens in the muscle fiber.

Question 65

Which of the following statements about cartilage and bone is false?

A) Some vertebrates are composed entirely of cartilage, with no bone.
B) Some vertebrates are composed entirely of bone, with no cartilage.
C) Bone has crystals of calcium phosphate.
D) The endoskeleton in many vertebrates serves as a reservoir of calcium.
E) The principal protein in cartilage is collagen.

Question 66

An annelid moves by

A) stretching its longitudinal muscles and pushing its fluid-filled body cavity forward.
B) forming pseudopods.
C) ciliary movement.
D) alternating contractions of longitudinal and circular muscles.
E) contraction of circular muscles, which puts pressure on the hydrostatic skeleton and causes it to extend.

Question 67

A benefit of an arthropod's exoskeleton is that it

A) protects against abrasion.
B) prevents water loss.
C) provides attachment sites for muscles.
D) bends at the animal's joints.
E) All of the above

Question 68

Given the total energy supply in the human body (in the form of ATP and creatine phosphate), how long is it possible to sit at rest without replenishing the supply?

A) 30 seconds
B) 10 minutes
C) 5 minutes
D) 30 minutes
E) 1 second

Question 69

Which of the following statements about bone is false?

A) When astronauts spend long periods of time in zero gravity, they experience decalcification of their bones.
B) Osteoclasts are derived from the lineage of cells that produce red blood cells.
C) Most bones have compact and cancellous regions.
D) Bones may become thicker or thinner depending on the amount of stress placed on them.
E) All of the above are true; none is false.

Question 70

Which of the following statements about the endoskeletons of vertebrates is false?

A) The muscles are attached to a living support structure.
B) The rib bones are part of the appendicular skeleton.
C) Molting is unnecessary in animals with endoskeletons.
D) Endoskeletons consist of bone and cartilage.
E) At least two bones are required to form a joint.

Question 71

An advantage of an endoskeleton over an exoskeleton is that it

A) provides muscle attachment sites.
B) provides protection.
C) grows as the animal grows.
D) supports the animal's weight.
E) gives structure to the animal.

Question 72

The exoskeleton of clams contains

A) calcium carbonate.
B) cartilage.
C) chitin.
D) collagen.
E) cuticle.

Question 73

Bone tissue consists of _______ cells in a matrix of _______.

A) osteocyte; polysaccharide
B) osteocyte; collagen and calcium phosphate
C) osteocyte; myosin and actin
D) collagen; calcium phosphate
E) collagen; polysaccharide

Question 74

Which of the following statements about exoskeletons is false?

A) During molting, the old exoskeleton is reabsorbed and a new exoskeleton forms.
B) A clam shell is an exoskeleton.
C) The arthropod cuticle is secreted by a layer of cells just below the exoskeleton.
D) The inner layer of the arthropod exoskeleton is used for muscle attachment.
E) The arthropod exoskeleton is a continuous covering that is thinned at the joints.

Question 75

Human bodies have which of the following types of joints?

A) Ball-and-socket
B) Hinge
C) Pivot
D) Saddle and ellipsoid
E) All of the above

Question 76

Which of the following statements about the effect of aerobic exercise on muscles is false?

A) Aerobic exercise increases the size, rather than the number, of muscle fibers.
B) Aerobic exercise increases the number of mitochondria.
C) Aerobic exercise increases the enzymes involved in energy use.
D) Aerobic exercise increases the density of capillaries delivering oxygen to the muscles.
E) Aerobic exercise increases the production of myoglobin.

Question 77

Osteoblasts cause bone to grow by

A) laying down new matrix until they are surrounded.
B) increasing the number of cells within the matrix.
C) laying down new matrix on bone surface.
D) tearing down old bone and depositing new bone.
E) tearing down old cartilage and depositing new bone.

Question 78

Haversian systems consist of

A) osteocytes that connect different cavities.
B) osteoblasts that will give rise to osteoclasts.
C) a meshwork of cancellous bone tissue.
D) cylindrical units surrounding a canal of blood vessels.
E) a reinforced system of bone that resists fracturing.

Question 79

The role of cartilage in the skeleton is to

A) bear heavy loads.
B) add flexibility.
C) be lightweight.
D) sustain vibrations.
E) grow rapidly.

Question 80

Long bones begin as _______ bones. At maturity, the shaft of a long bone consists of a _______ of _______ bone.

A) dermal; cylinder; compact
B) dermal; solid rod; cancellous
C) cartilage; cylinder; compact
D) cartilage; cylinder; cancellous
E) cartilage; solid rod; compact