Deck 11: Muscular Tissue

Question 1

The sarcoplasmic reticulum is the smooth endoplasmic reticulum of a muscle fiber.

Answer 1

True

Question 2

Shortening a muscle while it maintains constant tension is called __________.

A)complete tetanus
B)incomplete tetanus
C)an isokinetic contraction
D)an isometric contraction
E)an isotonic contraction

Answer 2

E

Question 3

An isometric contraction does not change muscle length.

Answer 3

True

Question 4

During muscle contraction,a single myosin head consumes ATP at a rate of about __________ ATP per second.

A)1
B)3
C)5
D)7
E)9

Question 5

Some smooth muscle is autorhythmic.

Question 6

The sliding filament theory of muscle contraction has emerged from research only in the last 10 to 15 years.

Question 7

All muscle types will respond to an electrical stimulus because all muscle cells are _________.

A)excitable
B)contractile
C)striated
D)involuntary
E)isometric

Question 8

A dark band formed by parallel thick filaments that partly overlap the thin filaments is known as an H band.

Question 9

Which of the following is not a purpose of the excess postexercise oxygen consumption (EPOC)in muscle?

A)To neutralize carbon dioxide buildup
B)To replenish the phosphagen system
C)To oxidize lactic acid
D)To serve elevated metabolic rate
E)To restore resting levels of ATP and CP

Question 10

80% of the lactic acid produced by skeletal muscle is converted to pyruvic acid by the __________.

A)kidneys
B)liver
C)muscle tissue
D)sarcoplasmic reticulum
E)neuromuscular junction

Question 11

Clinically,dystrophin is the most important noncontractile protein to occur in muscle fibers.

Question 12

Which of the following is predominately made up of myosin?

A)G actin
B)F actin
C)The thin filament
D)The thick filament
E)The elastic filament

Question 13

When a skeletal muscle lengthens,its __________ helps resist excessive stretching and subsequent injury to the muscle.

A)thick filaments
B)collagen
C)actin
D)troponin-tropomyosin complex
E)varicosities

Question 14

Extensibility refers to the ability of a muscle to stretch.

Question 15

A deficiency of acetylcholine receptors leads to muscle paralysis in myasthenia gravis.

Question 16

Which of the following marks the boundaries of a sarcomere?

A)I bands
B)H bands
C)Z discs
D)M lines
E)A bands

Question 17

Skeletal muscle is called ___________,because it is usually subject to conscious control.

A)excitable
B)contractile
C)striated
D)voluntary
E)isometric

Question 18

Which muscle type depends solely on the sarcoplasmic reticulum as its calcium source?

A)Skeletal muscle
B)Smooth muscle
C)Cardiac muscle
D)Skeletal and smooth muscle
E)Smooth and cardiac muscle

Question 19

Which muscle(s)can contract without the need for nervous stimulation?

A)Skeletal muscle only
B)Smooth muscle only
C)Cardiac muscle only
D)Smooth and cardiac muscle
E)Skeletal, smooth and cardiac muscle

Question 20

Which of the following contains overlapping thick and thin filaments?

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

Question 21

Where would you expect to find numerous gap junctions in muscular tissue?

A)The sarcoplasmic reticulum of skeletal muscle
B)The A bands of skeletal and cardiac muscle
C)The sarcolemma of skeletal muscle
D)The intercalated discs of cardiac muscle
E)Multiunit smooth muscle

Question 22

Which of the following has the largest mitochondria?

A)Slow oxidative fibers
B)Fast glycolytic fibers
C)Cardiac muscle
D)Smooth muscle
E)Intermediate fibers

Question 23

Which of the following is true concerning isotonic eccentric contraction?

A)The muscle shortens but tension remains constant.
B)The muscle lengthens but tension remains constant.
C)The muscle tenses and shortens.
D)The muscle tenses but length remains unchanged.
E)The muscle lengthens and tension declines.

Question 24

Aerobic respiration produces approximately _________ more ATPs per glucose molecule than glycolysis does.

A)12
B)24
C)36
D)48
E)100

Question 25

Athletes who train at high altitudes increase their red blood cell count,which increases their oxygen supply during exercise.Increased oxygen supply results in __________.

A)increased glycolysis
B)increased use of myokinase
C)longer aerobic respiration
D)longer anaerobic fermentation
E)reduced ATP consumption

Question 26

If one nerve stimulus arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch,the most likely result will be __________.

A)fatigue
B)spasm
C)incomplete tetanus
D)complete tetanus
E)flaccid paralysis

Question 27

To stimulate muscle contraction,acetylcholine is released from the ___________ into the synaptic cleft.

A)synaptic vesicles
B)junctional folds
C)sarcoplasmic reticulum
D)sarcolemma
E)terminal cisterna

Question 28

Which of the following would be caused by a contraction of smooth muscle?

A)Goose bumps
B)Blood leaving the left ventricle of the heart
C)Elevating the eyebrows
D)Blinking the eyelids
E)Deep inspiration

Question 29

Which fibers are primarily responsible for producing lactic acid?

A)Type I slow oxidative fibers
B)Type IIA intermediate glycolytic fibers
C)Type IIB fast glycolytic fibers
D)Type I slow-twitch fibers
E)Red fibers

Question 30

The minimum stimulus needed to cause muscle contraction is called the __________.

A)threshold
B)latent period
C)twitch
D)motor unit
E)innervation

Question 31

How many muscle fibers stimulate one somatic motor neuron?

A)0
B)1
C)2
D)3
E)4

Question 32

The process of engaging more motor units to increase the strength of a muscle contraction is called __________.

A)wave summation
B)recruitment
C)temporal summation
D)incomplete tetanus
E)complete tetanus

Question 33

Which of the following is an accurate comparison of skeletal muscle to smooth muscle?

A)Smooth muscle contracts more slowly but relaxes more rapidly.
B)Smooth muscle contracts more rapidly but relaxes more slowly.
C)Smooth muscle contracts and relaxes more slowly.
D)Smooth muscle consumes more ATP to maintain a given level of muscle tension.
E)Smooth muscle depends on a nerve fiber to supply the calcium needed for contraction.

Question 34

The triads of a muscle fiber consist of __________.

A)two A bands and one I band
B)two T tubules and one terminal cisterna
C)two terminal cisternae and one T tubule
D)two thin myofilaments and one thick myofilament
E)two thick myofilaments and one thin myofilament

Question 35

In order for muscle to continue contracting during anaerobic fermentation,which of the following is essential?

A)Cholinesterase inhibitors
B)Protease
C)Myokinase
D)Acetylcholinesterase
E)Acid phosphatase

Question 36

Which statement best describes the goal of medications used to treat myasthenia gravis?

A)To increase the number of acetylcholine receptors
B)To decrease the number of synaptic vesicles
C)To promote multiple motor unit summation
D)To inhibit Ca²⁺ release from the sarcoplasmic reticulum
E)To inhibit the function of cholinesterase

Question 37

Cardiac muscle has very little capacity for regeneration because it lacks __________.

A)satellite cells
B)an endomysium
C)sarcomeres
D)dense bodies
E)somatic nerve fibers

Question 38

Why is the contraction strength of smooth muscle relatively independent of its resting length?

A)It gets nearly all of its Ca²⁺ from the extracellular fluid.
B)It does not have intercalated discs.
C)It does not have sarcomeres.
D)It is regulated by a length-tension relationship.
E)It is involuntary muscle.

Question 39

Michael Jordan was arguably the best player in professional basketball history.Scientifically,one would expect him to have highly developed __________ fibers.

A)red
B)white
C)intermediate
D)fast twitch
E)slow oxidative

Question 40

The absence or inhibition of acetylcholinesterase at a synapse would lead to __________.

A)flaccid paralysis
B)tetanus
C)atrophy
D)numbness
E)muscle wasting

Question 41

Which of the following is not a characteristic of a muscle cell?

A)Plasticity
B)Contractility
C)Conductivity
D)Extensibility
E)Excitability

Question 42

As you are lifting a box,someone places extra weight on top of it.For your muscle to continue contracting and lifting the box,the muscle must __________.

A)recruit more muscle fibers
B)lower its threshold
C)reduce its wave summation
D)shift from isometric to isotonic contraction
E)shift from slow-twitch to fast-twitch mode

Question 43

What is the purpose of motor nerve varicosities as they relate to smooth muscle?

A)They link the thin filaments to the inside of the sarcolemma in smooth muscle.
B)They reabsorb the decomposition products of acetylcholine after acetylcholinesterase breaks it down.
C)They enable each cardiac myocyte to directly stimulate its neighbors.
D)They release neurotransmitter onto smooth muscle cells.
E)They prevent single-unit smooth muscle cells from pulling apart.

Question 44

Drugs called calcium channel blockers may be used to lower blood pressure by causing arteries to vasodilate.How do you suppose these drugs work?

A)They prevent calcium from entering the sarcoplasmic reticulum of smooth muscle.
B)They stimulate the calcium pump in smooth muscle, thus removing calcium from the calmodulin.
C)They prevent calcium from exiting the sarcoplasmic reticulum in skeletal muscle.
D)They prevent calcium from entering cardiac muscle, thus slowing down the heart rate.
E)They prevent calcium from entering smooth muscle, thus allowing the muscle to relax.

Question 45

Which of the following best describes the resting membrane potential (RMP)?

A)The intracellular environment is negatively charged.
B)The intracellular environment has more positively charged sodium.
C)The extracellular environment is negatively charged.
D)It has a voltage of about +75 mV.
E)It is dependent upon the absorption of potassium ions by the muscle fiber.

Question 46

What is the purpose of the triad?

A)The triad stores sodium.
B)The triad synthesizes ATP.
C)The triad maintains the resting membrane potential.
D)The triad removes acetylcholine from the synaptic cleft.
E)The triad allows for Ca²⁺ release when a muscle fiber is excited.

Question 47

The sarcolemma of a resting muscle fiber is most permeable to __________.

A)calcium
B)potassium
C)sodium
D)lithium
E)magnesium

Question 48

A myofilament that runs throught the core of a thick filament and anchors it to a Z disc is called a(n)__________.

A)myofibril
B)thin filament
C)T tubule
D)sarcolemma
E)elastic filament

Question 49

Which of the following individuals would have more mitochondria in her skeletal muscle?

A)A 50-year-old sedentary computer programmer
B)A 22-year-old soccer player
C)A long-term hospice patient
D)A model on a reduced-calorie diet
E)A newborn

Question 50

Which of the following systems would provide energy for a racquetball player,while playing a point?

A)The respiratory system
B)The glycolysis system
C)The phosphagen system
D)The anaerobic system
E)The glycogen-lactic acid system

Question 51

Exposure to the bacterium Clostridium tetani causes continuous release of acetylcholine.What effect does this have on smooth muscle?

A)Flaccid paralysis
B)Spastic paralysis
C)Lockjaw
D)No effect
E)Myocardial atrophy

Question 52

When acetylcholinesterase outlasts the release of acetylcholine from the synaptic vesicles,the skeletal muscle __________.

A)contracts
B)gets stronger
C)relaxes
D)releases Ca⁺⁺
E)opens its Na⁺ channels

Question 53

Which of the following is a property of collagen?

A)Contractility
B)Excitability
C)Elasticity
D)Expendability
E)Impermeability

Question 54

A skeletal muscle generates the greatest tension when it is __________.

A)greatly stretched before being stimulated
B)partially stretched before being stimulated
C)fully relaxed before being stimulated
D)well-rested and low in creatine phosphate
E)high in lactic acid concentration

Question 55

The protein that acts as a calcium receptor in skeletal muscle is __________.

A)F actin
B)tropomyosin
C)troponin
D)titin
E)dystrophin

Question 56

The synaptic knob releases acetylcholine into the synaptic cleft,which is received by receptors on the motor end plate.Which structure does this describe?

A)A sarcomere
B)The thick filament
C)The varicosity of a smooth muscle cell
D)The neuromuscular junction of a skeletal muscle
E)A motor unit

Question 57

Loss of muscle mass from lack of activity is called __________.

A)myopathy
B)dystrophy
C)apathy
D)atrophy
E)tetanus

Question 58

Where is dystrophin,the protein that is defective in muscular dystrophy,normally found?

A)Between the outermost myofilaments and the sarcolemma of a muscle fiber
B)As a transmembrane protein of the sarcolemma
C)In the Z discs of skeletal and cardiac muscle
D)In the dense bodies of smooth muscle
E)Bridging the gap between the sarcolemma and synaptic knob

Question 59

The transfer of phosphate from CP to ADP is catalyzed by __________.

A)myokinase
B)creatinine
C)cAMP
D)creatine kinase
E)ATP

Question 60

What happens when acetylcholine stimulates its receptors in the neuromuscular junction?

A)The release of Ca²⁺ from the sarcoplasmic reticulum decreases.
B)The permeability of the sarcolemma to Na⁺ increases.
C)The positive charge on the sarcolemma decreases.
D)The threshold of the muscle fiber lowers.
E)The inhibitory effect of acetylcholinesterase is overridden.

Question 61

Why does one continue to breathe heavy after rigorous physical activity has stopped?

A)The diaphragm is waiting for its acetylcholine to run out.
B)The body requires more oxygen to restore levels of ATP and creatine phosphate.
C)The lungs can't stop breathing until the heart rate slows down.
D)Myosin heads need more oxygen to fully detach from actin.
E)The kidneys require oxygen to dispose of excess lactic acid.

Question 62

In skeletal muscle,the term that describes the alternating light and dark bands is ___________.

A)strabismus
B)striations
C)tetanus
D)myofibrils
E)myoblasts

Question 63

A volleyball player depends on the gastrocnemius muscles for plantar flexion,whereas a marathon runner depends more on the soleus muscles for the same action.What characteristic of the soleus muscles makes this so?

A)They have smaller mitochondria.
B)They have more glycogen in them.
C)They don't have as many blood capillaries per gram of tissue.
D)They make more use of aerobic respiration.
E)They break ATP down to ADP and P_i faster.

Question 64

The training regimen of a competitive weight lifter is designed partly to __________.

A)convert certain parallel muscles into stronger pennate muscles
B)increase the average number of myofibrils per muscle fiber
C)convert white muscle tissue to red muscle
D)increase the size of his motor units
E)lower the threshold for muscle excitation