Deck 9: Muscles and Muscle Tissue

Question 1

Which of the choices below does not describe how recovery oxygen uptake oxygen deficit)restores metabolic conditions?

A)converts lactic acid back into glycogen stores in the liver
B)increases the level of lactic acid in the muscle
C)replaces the oxygen removed from myoglobin
D)resynthesizes creatine phosphate and ATP in muscle fibers

Answer 1

B

Question 2

During vigorous exercise,there may be insufficient oxygen available to completely break down pyruvic acid for energy.As a result,the pyruvic acid is converted to .

A)lactic acid
B)hydrochloric acid
C)stearic acid
D)a strong base

Answer 2

A

Question 3

Which of the following would be recruited later in muscle stimulation when contractile strength increases?

A)motor units with larger,less excitable neurons
B)motor units with the longest muscle fibers
C)large motor units with small,highly excitable neurons
D)many small motor units with the ability to stimulate other motor units

Answer 3

A

Question 4

Smooth muscles that act like skeletal muscles but are controlled by autonomic nerves and hormones are .

A)red muscles
B)white muscles
C)single- unit muscles
D)multiunit muscles

Question 5

After nervous stimulation stops,what prevents ACh in the synaptic cleft from continuing to stimulate contraction?

A)the action potential stops going down the overloaded T tubules
B)the tropomyosin blocking the myosin once full contraction is achieved
C)acetylcholinesterase destroying the ACh
D)calcium ions returning to the terminal cisternae

Question 6

Muscle tissue has all of the following properties except .

A)secretion
B)excitability
C)extensibility
D)contractility

Question 7

Of the following muscle types,which has only one nucleus,no sarcomeres,and rare gap junctions?

A)cardiac muscle
B)skeletal muscle
C)visceral smooth muscle
D)multiunit smooth muscle

Question 8

Which of the following statements is true?

A)Smooth muscle cells have T tubules.
B)Cardiac muscle cells have many nuclei.
C)Cardiac muscle cells are found in the heart and large blood vessels.
D)Striated muscle cells are long and cylindrical with many nuclei.

Question 9

When a muscle is unable to respond to stimuli temporarily,it is in which of the following periods?

A)refractory period
B)latent period
C)relaxation period
D)fatigue period

Question 10

Which of the following statements is false or incorrect?

A)Cardiac muscle contracts when stimulated by its own autorhythmic muscle cells.
B)Cardiac muscle fibers depend mostly on anaerobic cellular respiration to generate ATP.
C)Under normal resting conditions,cardiac muscle tissue contracts and relaxes about 75 times per minute.
D)Cardiac muscle fibers can use lactic acid to make ATP.

Question 11

What controls the force of muscle contraction?

A)multimotor unit summation
B)treppe
C)concentric contractions
D)wave summation

Question 12

What part of the sarcolemma contains acetylcholine receptors?

A)any part of the sarcolemma
B)part adjacent to another muscle cell
C)end of the muscle fiber
D)motor end plate

Question 13

An anaerobic metabolic pathway that results in the production of two net ATPs per glucose plus two pyruvic acid molecules is .

A)glycolysis
B)the electron transport chain
C)the citric acid cycle
D)hydrolysis

Question 14

During muscle contraction,myosin cross bridges attach to which active sites?

A)Z discs
B)thick filaments
C)myosin filaments
D)actin filaments

Question 15

What is the role of calcium ions in muscle contraction?

A)increase levels of myoglobin
B)bind to regulatory sites on troponin to remove contraction inhibition
C)form hydroxyapatite crystals
D)reestablish glycogen stores

Question 16

The major function of the sarcoplasmic reticulum in muscle contraction is to .

A)regulate intracellular calcium concentration
B)make and store phosphocreatine
C)provide a source of myosin for the contraction process
D)synthesize actin and myosin myofilaments

Question 17

Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the period during which the events of excitation- contraction coupling occur.

A)contraction
B)latent
C)refractory
D)relaxation

Question 18

Hypothetically,if a muscle were stretched to the point where thick and thin filaments no longer overlapped,.

A)maximum force production would result because the muscle has a maximum range of travel
B)no muscle tension could be generated
C)ATP consumption would increase because the sarcomere is "trying" to contract
D)cross bridge attachment would be optimum because of all the free binding sites on actin

Question 19

Excitation- contraction coupling requires which of the following substances?

A)Ca2+ only
B)ATP and glucose
C)ATP only
D)Ca2+ and ATP

Question 20

What is the functional unit of a skeletal muscle called?

A)a myofibril
B)the sarcoplasmic reticulum
C)a myofilament
D)a sarcomere

Question 21

Three discrete types of muscle fibers are identified on the basis of their size,speed,and endurance.Which of the following athletic endeavors best represents the use of red fibers?

A)a long,relaxing swim
B)mountain climbing
C)a sprint by an Olympic runner
D)playing baseball or basketball

Question 22

Myoglobin _.

A)stores oxygen in muscle cells
B)produces the end plate potential
C)breaks down glycogen
D)is a protein involved in the direct phosphorylation of ADP

Question 23

What is the most distinguishing characteristic of muscle tissue?

A)the diversity of activity of muscle tissue
B)the design of the fibers
C)the sarcoplasmic reticulum
D)the ability to transform chemical energy into mechanical energy

Question 24

What is the functional role of the T tubules?

A)synthesize ATP to provide energy for muscle contraction
B)enhance cellular communication during muscle contraction
C)stabilize the G and F actin
D)hold cross bridges in place in a resting muscle

Question 25

Fatigued muscle cells that recover rapidly are the products of _ .

A)slow exercise of long duration
B)intense exercise of long duration
C)intense exercise of short duration
D)slow exercise of short duration

Question 26

The giant protein titin maintains the organization of the assisting in muscle stretching.

A)M line
B)Z disc
C)I band
D)A band

Question 27

Which of the following is not a role of ionic calcium in muscle contraction?

A)removes contraction inhibitor
B)activates epinephrine released from adrenal gland
C)triggers neurotransmitter secretion
D)promotes breakdown of glycogen and ATP synthesis

Question 28

In an isotonic contraction,the muscle .

A)does not change in length but increases tension
B)changes in length and moves the "load"
C)never converts pyruvate to lactate
D)rapidly resynthesizes creatine phosphate and ATP

Question 29

What does oxygen deficit represent?

A)the amount of oxygen taken into the body immediately after the exertion
B)the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used
C)the amount of oxygen taken into the body prior to the exertion
D)amount of energy needed for exertion

Question 30

Which of the following is the correct sequence of events for muscle contractions?

A)neurotransmitter release,muscle cell action potential,motor neuron action potential,release of calcium ions from SR,sliding of myofilaments,ATP- driven power stroke
B)neurotransmitter release,motor neuron action potential,muscle cell action potential,release of calcium ions from SR,ATP- driven power stroke
C)motor neuron action potential,neurotransmitter release,muscle cell action potential,release of calcium ions from SR,ATP- driven power stroke,sliding of myofilaments
D)muscle cell action potential,neurotransmitter release,ATP- driven power stroke,calcium ion release from SR,sliding of myofilaments

Question 31

What produces the striations of a skeletal muscle cell?

A)a difference in the thickness of the sarcolemma
B)the arrangement of myofilaments
C)the T tubules
D)the sarcoplasmic reticulum

Question 32

What structure in skeletal muscle cells functions in calcium storage?

A)myofibrillar network
B)sarcoplasmic reticulum
C)intermediate filament network
D)mitochondria

Question 33

Which of the following describes the cells of single- unit visceral muscle?

A)They are chemically coupled to one another by gap junctions.
B)They exhibit spontaneous action potentials.
C)They consist of muscle fibers that are structurally independent of each other.
D)They contract all at once.

Question 34

What is the role of tropomyosin in skeletal muscles?

A)Tropomyosin is the receptor for the motor neuron neurotransmitter.
B)Tropomyosin is the name of a contracting unit.
C)Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.
D)Tropomyosin serves as a contraction inhibitor by blocking the actin binding sites on the myosin molecules.

Question 35

The main effect of the warm- up period of athletes,as the muscle contractions increase in strength,is to .

A)tone the muscles and stabilize the joints for the workout
B)increase the myoglobin content
C)convert glycogen to glucose
D)enhance the availability of calcium and the efficiency of enzyme systems

Question 36

Rigor mortis occurs because .

A)no ATP is available to release attached actin and myosin molecules
B)sodium ions leak out of the muscle
C)proteins are beginning to break down,thus preventing a flow of calcium ions
D)the cells are dead

Question 37

The oxygen- binding protein found in muscle cells is .

A)immunoglobin
B)ATP
C)hemoglobin
D)myoglobin

Question 38

The muscle cell membrane is called the .

A)endomysium
B)epimysium
C)perimysium
D)sarcolemma

Question 39

Muscle tone is _ .

A)a state of sustained partial contraction
B)the feeling of well- being following exercise
C)the condition of athletes after intensive training
D)the ability of a muscle to efficiently cause skeletal movements

Question 40

The sliding filament model of contraction involves .

A)actin and myosin shortening but not sliding past each other
B)the shortening of thick filaments so that thin filaments slide past
C)actin and myosin sliding past each other and partially overlapping
D)the Z discs sliding over the myofilaments

Question 41

Smooth muscle is characterized by all of the following except .

A)there are noncontractile intermediate filaments that attach to dense bodies within the cell
B)there are no sarcomeres
C)there are more thick filaments than thin filaments
D)it appears to lack troponin

Question 42

How do the three muscle types respond to being stretched?

Question 43

Which of the following is not a usual result of resistance exercise?

A)increase in the number of muscle cells
B)increase in the efficiency of the circulatory system
C)increase in the number of myofibrils within the muscle cells
D)increase in the efficiency of the respiratory system

Question 44

How is it that norepinephrine NE)can inhibit smooth muscle action in airways,yet stimulate contractions in smooth muscles everywhere else in the body?

Question 45

Which of the following are composed of myosin?

A)thin filaments
B)all myofilaments
C)Z discs
D)thick filaments

Question 46

The mechanism of contraction in smooth muscle is different from skeletal muscle in that _.

A)the site of calcium regulation differs
B)the trigger for contraction is a rise in intracellular calcium
C)actin and myosin interact by the sliding filament mechanism
D)ATP energizes the sliding process

Question 47

Which of the following is true about smooth muscle contraction?

A)Certain smooth muscle cells can actually divide to increase their numbers.
B)Smooth muscle,in contrast to skeletal muscle,cannot synthesize or secrete any connective tissue elements.
C)Smooth muscle has well- developed T tubules at the site of invagination.
D)Smooth muscle cannot stretch as much as skeletal muscle.

Question 48

Most skeletal muscles contain _.

A)a predominance of fast oxidative fibers
B)muscle fibers of the same type
C)a predominance of slow oxidative fibers
D)a mixture of fiber types

Question 49

Which of the following surrounds the individual muscle cell?

A)epimysium
B)fascicle
C)perimysium
D)endomysium

Question 50

Which of the following is a factor that affects the velocity and duration of muscle contraction?

A)number of muscle fibers stimulated
B)size of the muscle fibers stimulated
C)muscle length
D)load on the fiber

Question 51

Which of the following statements is most accurate?

A)Muscle tension remains relatively constant during isotonic contraction.
B)T tubules may be sliding during isotonic contraction.
C)Myofilaments slide during isometric contractions.
D)The I band lengthens during isotonic contraction.

Question 52

The tissue that binds muscles into functional groups.

Question 53

The time in which cross bridges are active is called the period of .

Question 54

A smooth,sustained contraction is called .

Question 55

The term aponeurosis refers to _ .

A)the bands of myofibrils
B)the rough endoplasmic reticulum
C)a sheetlike indirect attachment to a skeletal element
D)the tropomyosin- troponin complex

Question 56

The strongest muscle contractions are normally achieved by .

A)increasing the stimulation up to the maximal stimulus
B)increasing stimulus above the threshold
C)increasing stimulus above the treppe stimulus
D)recruiting small and medium muscle fibers

Question 57

The warm- up period required of athletes in order to bring their muscles to peak performance is called .

A)incomplete tetanus
B)treppe
C)wave summation
D)twitch

Question 58

What are the parts of the skeletal muscle triad and what are their functions?

Question 59

Which of the following is not a way muscle contractions can be graded?

A)changing the type of muscle fibers involved in the contraction
B)changing the frequency of stimulation
C)changing the strength of the stimulus
D)changing the type of neurotransmitter released by the motor neuron

Question 60

Creatine phosphate functions in the muscle cell by .

A)forming a temporary chemical compound with myosin
B)forming a chemical compound with actin
C)storing energy that will be transferred to ADP to resynthesize ATP
D)inducing a conformational change in the myofilaments

Question 61

Only muscle cells are always multinucleated.

Question 62

color)fibers are slow oxidative)fibers.

Question 63

Compare red and white muscles relative to their speed of action and endurance.

Question 64

In the synaptic cleft of a neuromuscular junction,an enzyme called is always present.

Question 65

What are caveolae?

Question 66

Only muscle cells commonly branch.

Question 67

The end of the muscle that typically moves when a muscle contracts is called the
.

Question 68

A long- distance runner is about to enter a 5- mile race.Beforehand,he spends several minutes warming up.During the warm- up period,the phenomenon of treppe is occurring in body muscles being used.What is treppe and why does it occur?

Question 69

What ultimately stops muscle stimulation when the motor neuron ceases firing?

Question 70

Define physiologic muscle fatigue.

Question 71

Briefly,what causes rigor mortis?

Question 72

Skeletal muscles have two special inclusions that help them perform their function of movement.What are the two special inclusions of skeletal muscle cells and how would they be useful to the cell?