Deck 9: Muscles and Muscle Tissue

Question 1

What is the primary function of wave summation?

A) produce smooth, continuous muscle contraction
B) prevent muscle fatigue
C) prevent muscle relaxation
D) increase muscle tension

Answer 1

A

Question 2

In an isotonic contraction, the muscle _ .

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

Answer 2

B

Question 3

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

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

Answer 3

B

Question 4

What is the role of calcium ions in muscle contraction?

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

Question 5

The contractile units of skeletal muscles are .

A) myofibrils
B) T tubules
C) mitochondria
D) microtubules

Question 6

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 7

Most skeletal muscles contain .

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

Question 8

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) acetylcholinesterase destroying the ACh
C) calcium ions returning to the terminal cisternae
D) the tropomyosin blocking the myosin once full contraction is achieved

Question 9

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

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

Question 10

Which of the following is not a connective tissue sheath that wraps individual muscle fibers?

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

Question 11

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

Question 12

Which of the following statements is most accurate?

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

Question 13

Rigor mortis occurs because .

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

Question 14

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

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

Question 15

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

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

Question 16

Which of the following is not a component of the standard treatment for muscle strain?

A) elevation of the limb
B) rest of the muscle
C) ice on the muscle
D) stretching of the muscle

Question 17

What is the functional role of the T tubules?

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

Question 18

Smooth muscle is characterized by all of the following except .

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

Question 19

Which muscle cells have the greatest ability to regenerate?

A) skeletal
B) cardiac
C) no muscle can regenerate
D) smooth

Question 20

What produces the striations of a skeletal muscle cell?

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

Question 21

Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the period during which the neurotransmitter is released by exocytosis, diffuses across the synaptic cleft, and binds to its receptors.

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

Question 22

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

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

Question 23

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

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

Question 24

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

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

Question 25

Fatigued muscle cells that recover rapidly are the products of .

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

Question 26

Which of the following surrounds the individual muscle cell?

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

Question 27

Excitation- contraction coupling requires which of the following substances?

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

Question 28

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

A) activates epinephrine released from adrenal gland
B) triggers neurotransmitter secretion
C) removes contraction inhibitor
D) binds with troponin

Question 29

Myoglobin _.

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

Question 30

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 31

Muscle tissue has all of the following properties except .

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

Question 32

The oxygen- binding protein found in muscle cells is .

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

Question 33

The term aponeurosis refers to .

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

Question 34

The muscle cell membrane is called the .

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

Question 35

Which of the following describes the cells of unitary smooth muscle?

A) They are used for vision and hair raising.
B) They exhibit spontaneous action potentials.
C) They depend upon recruitment using the autonomic nervous system.
D) They consist of muscle fibers that are structurally independent of each other.

Question 36

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

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

Question 37

What is the most distinguishing characteristic of muscle tissue?

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

Question 38

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

Question 39

Muscle tone is _ .

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

Question 40

What structure in skeletal muscle cells functions in calcium storage?

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

Question 41

Figure 9.1
Using Figure 9.1, match the following:
Bundle of muscle cells surrounded by a perimysium

Question 42

What is the role of tropomyosin in skeletal muscles?

A) Tropomyosin serves as a contraction inhibitor by blocking the actin binding sites on the myosin molecules.
B) Tropomyosin is the chemical that activates the myosin heads.
C) Tropomyosin is the receptor for the motor neuron neurotransmitter.
D) Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.

Question 43

Which of the following statements is true?

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

Question 44

What does excess postexercise oxygen consumption represent?

A) the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used
B) amount of oxygen needed for aerobic activity to accomplish the same amount of work
C) the amount of oxygen equal to the oxygen already used
D) the amount of oxygen taken into the body immediately after the exertion

Question 45

Figure 9.2
Using Figure 9.2, match the following:
H zone.

Question 46

Which of the following is true about smooth muscle?

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

Question 47

Creatine phosphate functions in the muscle cell by .

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

Question 48

Figure 9.2
Using Figure 9.2, match the following:
What ultimately stops muscle stimulation when the motor neuron ceases firing?

Question 49

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

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

Question 50

The sliding filament model of contraction involves .

A) the Z discs sliding over the myofilaments
B) actin and myosin sliding past each other and partially overlapping
C) the shortening of thick filaments so that thin filaments slide past
D) actin and myosin lengthening in order to slide past each other

Question 51

What is the functional unit of a skeletal muscle called?

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

Question 52

Which of the choices below does not describe how excess postexercise oxygen consumption (oxygen deficit) restores metabolic conditions?

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

Question 53

Figure 9.2
Using Figure 9.2, match the following:
M line.

Question 54

The strongest muscle contractions are normally achieved by _ .

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

Question 55

Define physiologic muscle fatigue.

Question 56

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

Question 57

What are caveolae?

Question 58

Figure 9.1
Using Figure 9.1, match the following:
The time in which cross bridges are active is called the period of .

Question 59

What part of the sarcolemma contains acetylcholine receptors?

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

Question 60

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

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

Question 61

Which cells help repair injured skeletal muscle fibers and allow regeneration of dead skeletal muscle?

Question 62

Briefly, what causes rigor mortis?

Question 63

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

Question 64

Figure 9.1
Using Figure 9.1, match the following:
Individual muscle fiber.

Question 65

Figure 9.2
Using Figure 9.2, match the following:
I band.

Question 66

Only muscle cells are always multinucleated.

Question 67

How do the three muscle types respond to being stretched?

Question 68

Figure 9.1
Using Figure 9.1, match the following:
Connective tissue covering the exterior of a muscle organ.

Question 69

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

Question 70

Figure 9.1
Using Figure 9.1, match the following:
What is a muscle spasm?

Question 71

What is muscle tension?

Question 72

Figure 9.2
Using Figure 9.2, match the following:
Z disc.

Question 73

Figure 9.2
Using Figure 9.2, match the following:
A smooth, sustained contraction from rapid stimulation is called _ .

Question 74

Briefly explain the sources of energy for a one- minute sustained muscle contraction.

Question 75

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

Question 76

Figure 9.1
Using Figure 9.1, match the following:
Only muscle cells commonly branch.

Question 77

Figure 9.1
Using Figure 9.1, match the following:
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?

Question 78

Figure 9.1
Using Figure 9.1, match the following:
Connective tissue surrounding muscle fiber bundles

Question 79

Figure 9.2Using Figure 9.2, match the following:
A band.

Question 80

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