Deck 11: Muscular Tissue

Question 1

Which is predominately made up of myosin?

A)1
B)2
C)3
D)4
E)5

Answer 1

D

Question 2

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

Answer 2

False

Question 3

During muscle contraction, a single myosin head consumes ATP at a rate of about

A)1 ATP per second.
B)3 ATP per second.
C)5 ATP per second.
D)7 ATP per second.
E)9 ATP per second.

Answer 3

C

Question 4

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

Question 5

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)intercalated discs of cardiac muscle
E)multiunit smooth muscle

Question 6

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

Question 7

Which band contains overlapping thick and thin filaments?

A)1
B)2
C)3
D)4
E)5

Question 8

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

A)skeletal muscle
B)smooth muscle
C)cardiac muscle
D)smooth and cardiac muscle
E)skeletal, smooth and cardiac muscle

Question 9

An isometric contraction does not change muscle length.

Question 10

Extensibility refers to the ability of a muscle to stretch.

Question 11

Some smooth muscle is autorhythmic.

Question 12

The contraction strength of smooth muscle is relatively independent of its resting length partly because

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 13

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 14

The term for shortening of a muscle while maintaining constant tension is

A)treppe.
B)tetanus.
C)isokinetic contraction.
D)isometric contraction.
E)isotonic contraction.

Question 15

Which of the following is not a purpose of the excess postexercise oxygen consumption 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 16

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

Question 17

Which marks the boundaries of a sarcomere?

A)1
B)2
C)3
D)4
E)5

Question 18

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

Question 19

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

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

Question 20

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 21

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 22

Exposure to 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 23

Cardiac muscle has very little capacity for regeneration because it lacks

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

Question 24

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 25

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 26

The absence or inhibition of acetylcholinesterase at a synapse would lead to which of the following?

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

Question 27

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

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

Question 28

Which of the following would be caused by 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

The minimum stimulus needed to cause muscle contraction is called

A)the threshold.
B)the latent period.
C)twitch.
D)recruitment.
E)innervation.

Question 30

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)treppe.
C)incomplete tetanus.
D)complete tetanus.
E)flaccid paralysis.

Question 31

Which of the following is very important for muscle to continue contraction during anaerobic respiration?

A)cholinesterase inhibitors
B)protease
C)myokinase
D)acetylcholinesterase
E)acid phosphatase

Question 32

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

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

Question 33

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 34

The process of bringing more motor units into use during a muscle contraction is called

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

Question 35

Athletes who train at high altitudes increase their red blood cell count and thus increase 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 36

One somatic motor neuron is stimulated by how many muscle fibers?

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

Question 37

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 38

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

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

Question 39

Drugs called calcium channel blockers may be used to lower blood pressure by causing arteries to vasodilate.These drugs

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

Question 40

In comparison to skeletal muscle, smooth muscle

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

Question 41

Collagen is

A)contractile.
B)excitable.
C)elastic.
D)expendable.
E)impermeable.

Question 42

The purpose of varicosities in motor nerve fibers in muscle physiology is

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

Question 43

The sarcolemma of a resting muscle fiber is most permeable to

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

Question 44

Which of the following systems would provide energy for a racquetball player?

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

Question 45

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)in a state of treppe.

Question 46

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

A)plasticity
B)contractility
C)conductivity
D)extensibility
E)excitability

Question 47

A reason that muscle twitches become progressively stronger in treppe is

A)Ca₂+ accumulates in the sarcoplasm faster than the sarcoplasmic reticulum can reabsorb it.
B)ATP is regenerated faster than it is consumed.
C)myosin heads show faster and faster power strokes.
D)more and more acetytlcholine is released with each stimulus.
E)as the muscle warms up, aerobic respiration is accelerated.

Question 48

In skeletal muscle, alternating light and dark bands are termed

A)strabismus.
B)striations.
C)treppe.
D)myofibrils.
E)myoblasts.

Question 49

A myofilament that flanks a thick filament and anchors it to a Z disc is called

A)a myofibril.
B)a thin filament.
C)a myoglobin.
D)a sarcoplasm.
E)an elastic filament.

Question 50

Dystrophin, the protein that is defective in muscular dystrophy, is 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 51

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.This is because the soleus muscles

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

Question 52

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 football player
C)a long-term hospice patient
D)a model on a reduced-calorie diet
E)a newborn

Question 53

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 depends on the muscle fiber absorbing potassium ions from the ECF.

Question 54

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.

Question 55

Release of acetylcholine at a neuromuscular junction

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

Question 56

Loss of muscle mass from lack of activity is termed

A)myopathy.
B)dystrophy.
C)apathy.
D)atrophy.
E)treppe.

Question 57

The bladder's ability to greatly distend and return to normal tension is due to the of smooth muscles.

A)elasticity
B)longevity
C)tensile strength
D)plasticity
E)tone

Question 58

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.