Deck 45: The Musculoskeletal System

Question 1

Which of the following regarding bone growth is false?

A)Cartilage of growth plates actively grow in lengthwise direction.
B)Increase in bone thickness results from the adding of bone layers on top of the periosteum.
C)Some cartilage remains after it is replaced by bone.
D)Cartilage calcification encroaches on the cartilaginous growth plate.

Answer 1

B

Question 2

In a stimulated muscle fiber,the calcium ions released by the sarcoplasmic reticulum bind to the protein ________.

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

Answer 2

A

Question 3

You witness a demonstration of a martial arts master breaking a large concrete block with his hand.Besides mastering the technique,what is another benefit of the repetitive practice of breaking concrete?

A)Repetitive stress on the long bones will solidify cartilage.
B)The Haversian canal system will supply more blood and strengthen the bone.
C)The repetitive stress will lead to remodeling and strengthening of the long bones.
D)The marrow cavity will solidify and strengthen the bone.

Answer 3

C

Question 4

Insects such as mosquitoes and beetles can beat their wings at tremendous speeds.This can be accomplished because

A)their wing muscle contractions causes another set of muscles to stretch which in turn produces another contraction without waiting for the arrival of a nerve impulse.
B)their wing muscle contractions cause another set of muscles to relax which in turn produces another wing movement.
C)their wing muscle contractions are stimulated by the continuous nerve signal impulses which produce a continuous contraction of their wing muscles.
D)their wing muscle contractions are capable of producing more ATP which allows these insects to have much faster and sustained wing movements.
E)their wing muscle contractions produce nerve impulses which lead to more contraction of the wing muscles which in turn permits faster motion of the wings.

Question 5

Which of the bone development lineages is incorrect?

A)undifferentiated mesenchymal cells → osteocyte → osteoblast
B)undifferentiated mesenchymal cells → fibroblast → collagen
C)undifferentiated mesenchymal cells → chondroblast → chondrocyte
D)white blood cell progenitors → monocytes → osteoclast
E)undifferentiated mesenchymal cells → osteoblast → osteocyte

Question 6

You decide to do an experiment with isolated myofibrils to explore the effects of ATP hydrolysis on myofibril function.You do this by bathing the myofibrils in a solution that contains a modified form of ATP,which cannot be split into ADP and P_i. At what step will myofibril function be arrested by using this compound instead of unmodified ATP?

A)There will be no block in the cycle,since ATP hydrolysis is not required for this process.
B)Myosin molecules will be unable to assemble into thick filaments.
C)Myosin heads will be unable to bind to the actin filaments.
D)Myosin heads will bind to the actin filaments,but the power stroke will not occur and actin filaments will not slide over the myosin filaments.
E)The myosin heads will remain attached to the actin filaments after the power stroke.

Question 7

According to the figure,which one represents the muscle in an optimal condition for a strong contraction?

A)A
B)B
C)C
D)D

Question 8

Shown below is part of a myofibril from a relaxed muscle fiber.Which of the labeled regions will NOT shorten when the muscle contracts?

A)A band
B)H band
C)I band
D)Sarcomere

Question 9

Which animal does a dolphin or whale most resemble as it swims through water?

A)A running lizard
B)A running dog
C)A swimming shark
D)A swimming alligator
E)A swimming penguin

Question 10

As the Baby Boomer generation ages,more and more joint replacement surgeries take place each year.Hip replacement surgery is the gold standard of all joint replacement surgeries,with many patients able to walk just a few hours after surgery and return home the very next day.In contrast,knee replacement surgery usually requires hospital stays of several days,followed by weeks to months of physical therapy.What best explains why the recovery after hip replacement surgery is so much faster than after knee replacement surgery?

A)The hip joint is more superficial and more accessible to surgeons than the knee joint.
B)The knee joint is stabilized by many more structures (many of which have to be cut)than the hip joint.
C)The hip only moves in one direction,and recovery of one motion is easier than recovering movement in many directions.
D)The upper end of the thigh bone has less overall surface contact with the hip bone than its lower end has in the knee with bones of the lower leg.
E)The knee is a type of combination joint,which are difficult to replace.

Question 11

Which of the following is required to detach myosin from actin?

A)calcium
B)ATP
C)phosphate
D)troponin
E)ADP

Question 12

In arthropods,locomotion is accomplished by muscles that work against

A)each other.
B)the exoskeleton.
C)a hydrostatic skeleton.
D)mineralized bones.
E)the pseudocoel.

Question 13

The mammalian jaw is an example of what kind of moveable joint?

A)hinge joint
B)combination joint
C)gliding joint
D)ball-and-socket joint

Question 14

The use-dependent decrease in the ability of a muscle to generate force is called ________.

A)tetanus
B)aerobic fitness
C)fatigue
D)endurance

Question 15

The neurotransmitter released from the nerve terminus at the neuromuscular junction is ________.

A)troponin
B)Ca²⁺
C)tropomyosin
D)acetylcholine

Question 16

One adaptation to flight in birds is lighter bones,which lack

A)calcium.
B)collagen.
C)bone marrow.
D)the periosteum.
E)medullary cavities.

Question 17

Utilizing more motor units for stronger muscle contractions is called

A)fast-twitching.
B)fatigue.
C)aerobic capacity.
D)recruitment.
E)insertion.

Question 18

Which of the following regarding the Haversian System is false?

A)It keeps osteocytes alive.
B)Haversian canals may contain nerve fibers.
C)Haversian canals run parallel to the length of long bone.
D)Haversian canals are created by osteoclasts that tunnel through the bone matrix.

Question 19

Which of the following is the smallest unit in terms of size?

A)quadriceps
B)myofibril
C)muscle fiber
D)sarcomere
E)myofilaments

Question 20

The structure enabling depolarization to travel deep into the muscle fiber is the ________.

A)T tubule
B)sarcoplasmic reticulum
C)motor unit
D)sarcomere

Question 21

Impulses conducted along the transverse tubules of the muscle fiber stimulate

A)the release of ATP.
B)the binding of actin to the Z lines.
C)tropomyosin and troponin binding.
D)the release of calcium ions.
E)the release of acetylcholine.

Question 22

Sustained contraction is called

A)twitching.
B)summation.
C)tetanus.
D)recruitment.
E)isometric binding.

Question 23

Select the incorrect statement about muscle and muscle fibers.

A)A quick contraction and relaxation of an isolated skeletal muscle is called tetanus.
B)Long distance runners tend to have more slow-twitch muscle fibers than fast-twitch fibers.
C)Slow-twitch muscle fibers have high concentrations of myoglobin.
D)Fast-twitch fibers increase in size with resistance training.
E)Fast-twitch fibers have fewer capillaries and mitochondria than slow-twitch fibers.

Question 24

A muscle fiber contracts by a sequence of events initiated by the binding of acetylcholine to its receptor.Which of the following is the correct sequence? I-The calcium-troponin complex pulls tropomyosin away from the myosin binding sites of actin.
II-The freed-sites of actin bind to myosin to form cross bridges.
III-Calcium ion binds to the troponin.

A)I,III,and II
B)III,II,and I
C)II,III,and I
D)I,II,and III
E)III,I,and II

Question 25

In order for an earthworm to lengthen several contiguous segments of its body,it must

A)contract its circular muscles,which pulls up the chaetae and moves the body fluid parallel to the long axis of the worm.
B)contract its longitudinal muscles,which pulls up the chaetae and moves the body fluid perpendicular to the long axis of the worm.
C)contract its circular muscles,which extends the chaetae into the surrounding soil and moves the body fluid parallel to the long axis of the worm.
D)contract its longitudinal muscles,which extends the chaetae into the surrounding soil and moves the body fluid parallel to the long axis of the worm.
E)contract its circular muscles,which extends the chaetae into the surrounding soil and moves the body fluid perpendicular to the long axis of the worm.

Question 26

A cross bridge is the binding of which two proteins?

A)actin and myosin
B)actin and troponin
C)myosin and troponin
D)collagen and troponin
E)myosin and collagen

Question 27

Which of these muscles would you expect to have the greatest proportion of slow-twitch fibers?

A)the gastrocnemius
B)the soleus
C)the lateral rectus
D)chicken breast muscle

Question 28

Which of the following statements relating to skeletal muscle and their functions is NOT correct?

A)Skeletal muscles are attached to bones by tendons.
B)The origin of a skeletal muscle remains relatively stationary.
C)The end of the muscle called the insertion is attached to the bone that moves when the muscle contracts.
D)Contraction of the hamstring muscles extends your knee.
E)Muscles that produce opposing actions at a joint are called antagonists.

Question 29

What is the association between tropomyosin and troponin molecules in resting striated muscle fibers?

A)Tropomyosin holds the troponin in place on the myosin.
B)Troponin holds the tropomyosin in place on the myosin.
C)Tropomyosin holds the troponin in place on the actin.
D)Troponin holds the tropomyosin in place on the actin.
E)There is no known association.

Question 30

The muscles that move the eye have a high proportion of fast-twitch fibers and reach maximum tension very fast.These fibers belong to the class of ________ fibers.

A)type I
B)type II
C)type III
D)type IV
E)type V

Question 31

The movement of actin and myosin fibers in a muscle contraction contains all of the following steps EXCEPT

A)the myosin head attaches to the actin filament.
B)myosin rolls up from one end,forming a ball.
C)the myosin filament advances relative to the actin filament.
D)the globular myosin head detaches from the actin filament.
E)the myosin head returns to its original conformation.

Question 32

You have just read an advertisement for a new drug that claims people who take it can get muscular bodies without spending months lifting weights in the gym.The drug stimulates muscle growth in the same way that weight lifting does,which is to

A)stimulate growth in the size of existing muscle fibers.
B)stimulate existing muscle fibers to divide.
C)stimulate existing muscle fibers to fuse with one another.
D)turn surrounding connective tissue into muscle tissue.
E)stimulate an increase in the proportion of slow-twitch muscle fibers.

Question 33

Impressive was a champion Quarter Horse stallion with a magnificent muscular physique,a trait that he passed on to dozens of offspring.However,many of Impressive's offspring developed periodic muscular twitching that sometimes left the horses temporarily unable to move.Some horses even died.As it turns out,Impressive's award-winning physique was due to a mutation in a single,protein-encoding gene,resulting in hyperexcitable muscle (which contracts even in the absence of a stimulus from its motor neuron).Which is NOT a plausible explanation for the identity of the abnormal muscle protein in Impressive and his offspring?

A)acetylcholine receptors that function in the absence of acetylcholine
B)leaky Na⁺ channels
C)overactive Ca²⁺ pumps in the membrane of the sarcoplasmic reticulum
D)tropomyosin that is unable to bind to actin
E)over-active troponin molecules

Question 34

In order for a muscle to contract,calcium ions released from the sarcoplasmic reticulum must bind to

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

Question 35

Myofibril contractile subunits,the sarcomeres,are bounded on each end by a disc of protein called the

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

Question 36

Which of the following joint types is not correctly matched with its example?

A)ball-and-socket joint-femur and pelvis
B)gliding joint-vertebral column
C)immovable joint-skull sutures
D)hinge joint-finger joint
E)combination joint-knee joint

Question 37

Select the incorrect statement related to sarcomere structure and function.

A)Thin filaments are not present in the H band of a sarcomere.
B)Two Z lines form the opposite borders of one sarcomere.
C)Stacks of thick filaments produce dark bands,called the A band.
D)I bands consist of both thin and thick filaments.
E)sarcomeres are the smallest subunits of muscle contraction.

Question 38

In the power stroke shown in panel c below,the thin filaments are pulled towards the center of the sarcomere.What is the specific sequence of events that occurs during a power stroke?

A)Release of the phosphate group -> myosin head changes shape -> release of ADP
B)Release of the phosphate group -> release of ADP -> myosin head changes shape
C)Release of ADP -> myosin head changes shape -> release of the phosphate group
D)Myosin head changes shape -> release of the phosphate group -> release of ADP
E)Release of ADP-> release of the phosphate group -> myosin head changes shape

Question 39

All of the following statements about exoskeletons are correct EXCEPT

A)exoskeletons are made of chitin.
B)muscles are attached to the exoskeleton.
C)exoskeletons do not limit growth because they can stretch.
D)exoskeletons are shed by many arthropods in a process called molting.
E)chitin is a polysaccharide.

Question 40

A newborn baby dies soon after birth because her diaphragm and rib cage muscles failed to contract and she was unable to breathe on her own.Examination of the baby's DNA revealed that she had a genetic mutation in a gene that encoded a calcium-binding protein.Which protein was most likely defective in the baby?

A)actin
B)myosin
C)acetylcholine
D)tropomyosin
E)troponin

Question 41

The masseter muscles originate on your cheekbones and insert into the posterior corners of the mandible (the lower jaw bone)underneath your ears.Will contraction of the masseter muscles open or close your jaw?

A)close
B)open

Question 42

Imagine an earthworm that has no chaetae.How would the lack of chaetae affect movement of the earthworm?

A)The earthworm would not be able to move at all.
B)The earthworm would only be able to extend its body segments.
C)The earthworm would only be able to shorten its body segments.
D)The earthworm would have difficulty changing locations,since it cannot anchor itself in the soil.
E)The earthworm would be much flatter than normal since it has no hydrostatic skeleton.

Question 43

Impulses conducted along the muscle fiber's transverse tubules stimulate the release of calcium ions into the cytoplasm

A)from the sarcoplasmic reticulum.
B)from the actin and myosin subunits.
C)from the Z line.
D)from the extracellular fluid in the neuromuscular junction.
E)from the troponin.

Question 44

You are investigating the scene of a hit and run where somebody's pet dog was killed.It is a very hot day so the dog's body temperature is unlikely to yield any important information regarding the time of death.The dog's limbs are movable and there is no significant smell of rotting flesh.What is the best guess of the time of death?

A)within the last 10 minutes
B)within the last 2 hours
C)3-4 hours ago
D)24 hours ago

Question 45

Muscle fatigue is often accompanied by muscle pain.What is the most likely explanation for this pain?

A)decreased pH in the muscle fibers
B)decreased levels of glycogen in the muscle fibers
C)decreased levels of ATP in the muscle fibers
D)increased levels of P_i in the muscle fibers
E)the myofibrils being torn apart

Question 46

The human skeleton is a typical vertebrate

A)endoskeleton.
B)exoskeleton.
C)hydrostatic skeleton.
D)axial skeleton only.
E)appendicular skeleton only.

Question 47

Which of the following is/are required with actin and myosin in order to initiate muscle contraction?

A)ATP
B)calcium
C)phosphate
D)calcium and ATP
E)calcium and phosphate

Question 48

Based on the above diagram and other information from your text,what is the most likely (e.g.,most parsimonious)explanation for the evolution of flight in vertebrates?

A)Wings evolved once in vertebrates (e.g.,the common ancestor of all terrestrial vertebrates had wings)and wings were subsequently lost in all but three lineages: bats,pterosaurs and birds.
B)The common ancestor of all terrestrial vertebrates was wingless and wings evolved independently three different times: in bats,in pterosaurs and in birds.
C)The common ancestor of all terrestrial vertebrates was wingless and wings evolved independently two different times: once in bats and once in the common ancestor of birds,pterosaurs and dinosaurs.
D)The common ancestor of all terrestrial vertebrates was wingless and wings evolved independently three different times: in bats,in pterosaurs and in the common ancestor of birds and dinosaurs.
E)The common ancestor of all terrestrial vertebrates was wingless and wings evolved independently three different times: in bats,in birds and in the common ancestor of pterosaurs and dinosaurs.

Question 49

Vertebrate bone does NOT ________.

A)consist of cells and an extracellular matrix containing collagen fibers
B)contain hydroxyapatite crystals
C)contain sarcomere units
D)contain blood vessels
E)become remodeled with use

Question 50

The figure below represents a joint in the hind leg of a grasshopper.The exoskeleton of the leg is indicated by the two pairs of parallel black lines.A muscle that moves this leg is fixed to the skeleton at the end marked with a blue star.When the muscle contracts,it will pull on the tendon at its opposite end.Which configuration shows the most likely arrangement of the exoskeleton and a muscle that increases the flexion of this leg?

A)A
B)B
C)C
D)D

Question 51

A lab technician is preparing to dispose of a rat and a frog that were euthanized earlier in the day for a scientific study.Although the two animals died at the same time,the rat has rigor mortis while the frog does not yet show any signs of it.What is the best explanation for this time difference in the onset of rigor mortis?

A)The rat's muscles have a greater density of myofilaments than the frog's muscles.
B)The rat is able to synthesize more ATP than the frog.
C)The frog has lower concentrations of glycogen in its muscles than the rat.
D)The rat has higher concentrations of myoglobin in its muscles than the frog.
E)All the frog's muscles are fast-twitch muscles.

Question 52

If you rub the scaled skin of a shark,it feels rough if you move your hand from tail to head but smooth if you move from head to tail.What is a major advantage of the scales being oriented this way?

A)to counteract friction as the shark swims through the water
B)to keep the shark afloat in the water
C)to better protect the shark from predators
D)to better prevent water loss from the body tissues
E)to enable the shark to orient itself in space and detect prey

Question 53

What molecule contributes to the red color of slow-twitch muscle fibers?

A)glycogen
B)lactic acid
C)ATP
D)myoglobin
E)fatty acids

Question 54

Sarin gas is an inhibitor of an enzyme that functions in the neuromuscular junction to break down acetylcholine.What is the most likely description of how a person would die after inhaling this poisonous gas?

A)by a heart attack
B)paralysis of skeletal muscles
C)suffocation via tetanus,or constant stimulation,of the respiratory muscles
D)suffocation via paralysis,or a block in stimulation,of the respiratory muscles
E)epileptic convulsions caused by disorganized electrical activity in the brain

Question 55

Identify the condition that will result in an increased level of calcium in the blood.

A)inhibition of chondroblasts
B)inhibition of chondrocytes
C)excess osteoclast activity
D)excess osteocyte activity
E)excess osteoblast activity

Question 56

The myofibrils consist of both thin filaments made of actin and thick filaments composed of

A)myosin.
B)troponin.
C)chitin.
D)tropomyosin.
E)acetylcholine.

Question 57

In bone,crystals of calcium phosphate impregnate the extracellular matrix containing fibers of

A)actin.
B)chitin.
C)collagen.
D)myosin.
E)troponin.