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Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1)
What is the role of calcium ions in muscle contraction?
1)
A)
increase levels of myoglobin
B)
reestablish glycogen stores
C)
bind to regulatory sites on troponin to remove contraction inhibition
D)
form hydroxyapatite crystals
2)
Of the following muscle types, which has only one nucleus, no sarcomeres, and rare gap junctions?
2)
A)
cardiac muscle
B)
multiunit smooth muscle
C)
skeletal muscle
D)
visceral smooth muscle
3)
Which of the following is not a connective tissue sheath that wraps individual muscle fibers?
3)
A)
perimysium
B)
epimysium
C)
aponeurosis
D)
endomysium
4)
Rigor mortis occurs because ________.
4)
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
5)
When a muscle is unable to respond to stimuli temporarily, it is in which of the following periods?
5)
A)
relaxation period
B)
latent period
C)
refractory period
D)
fatigue period
6)
What is the functional role of the T tubules?
6)
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
7)
In an isotonic contraction, the muscle ________.
7)
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
8)
An anaerobic metabolic pathway that results in the production of two net ATPs per glucose plus
two pyruvic acid molecules is ________.
8)
A)
the citric acid cycle
B)
glycolysis
C)
the electron transport chain
D)
hydrolysis
9)
The contractile units of skeletal muscles are ________.
9)
A)
myofibrils
B)
T tubules
C)
mitochondria
D)
microtubules
10)
Which of the following is not a component of the standard treatment for muscle strain?
10)
A)
elevation of the limb
B)
rest of the muscle
C)
ice on the muscle
D)
stretching of the muscle
11)
Which muscle cells have the greatest ability to regenerate?
11)
A)
skeletal
B)
cardiac
C)
no muscle can regenerate
D)
smooth
12)
Which of the following is a factor that affects the velocity and duration of muscle
contraction?
12)
A)
load on the fiber
B)
number of muscle fibers stimulated
C)
size of the muscle fibers stimulated
D)
muscle length
13)
Which of the following statements is most accurate?
13)
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.
14)
What is the primary function of wave summation?
14)
A)
produce smooth, continuous muscle contraction
B)
prevent muscle fatigue
C)
prevent muscle relaxation
D)
increase muscle tension
15)
Smooth muscle is characterized by all of the following except ________.
15)
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
16)
Which of the following statements is false or incorrect?
16)
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.
17)
After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to
stimulate contraction?
17)
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
18)
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 ________.
18)
A)
hydrochloric acid
B)
a strong base
C)
lactic acid
D)
stearic acid
19)
Most skeletal muscles contain ________.
19)
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
20)
What produces the striations of a skeletal muscle cell?
20)
A)
a difference in the thickness of the sarcolemma
B)
the T tubules
C)
the sarcoplasmic reticulum
D)
the arrangement of myofilaments
21)
Hypothetically, if a muscle were stretched to the point where thick and thin filaments no longer
overlapped, ________.
21)
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
22)
Which of the following surrounds the individual muscle cell?
22)
A)
endomysium
B)
perimysium
C)
epimysium
D)
fascicle
23)
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.
23)
A)
relaxation
B)
latent
C)
refractory
D)
contraction
24)
The muscle cell membrane is called the ________.
24)
A)
sarcolemma
B)
epimysium
C)
perimysium
D)
endomysium
25)
The term aponeurosis refers to ________.
25)
A)
the bands of myofibrils
B)
the rough endoplasmic reticulum
C)
the tropomyosin-troponin complex
D)
a sheetlike indirect attachment to a skeletal element
26)
Which of the following is not a role of ionic calcium in muscle contraction?
26)
A)
activates epinephrine released from adrenal gland
B)
triggers neurotransmitter secretion
C)
removes contraction inhibitor
D)
binds with troponin
27)
The oxygen-binding protein found in muscle cells is ________.
27)
A)
myoglobin
B)
immunoglobin
C)
ATP
D)
hemoglobin
28)
During muscle contraction, myosin cross bridges attach to which active sites?
28)
A)
actin filaments
B)
myosin filaments
C)
Z discs
D)
thick filaments
29)
Excitation-contraction coupling requires which of the following substances?
29)
A)
Ca2+ only
B)
ATP only
C)
ATP and glucose
D)
Ca2+ and ATP
30)
Muscle tone is ________.
30)
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
31)
What structure in skeletal muscle cells functions in calcium storage?
31)
A)
myofibrillar network
B)
mitochondria
C)
intermediate filament network
D)
sarcoplasmic reticulum
32)
The major function of the sarcoplasmic reticulum in muscle contraction is to ________.
32)
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
33)
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?
33)
A)
gym climbing
B)
a long, relaxing swim
C)
playing baseball or basketball
D)
a sprint by an Olympic runner
34)
The giant protein titin maintains the organization of the ________ assisting in muscle stretching.
34)
A)
M line
B)
Z disc
C)
I band
D)
A band
35)
Which of the following describes the cells of unitary smooth muscle?
35)
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.
36)
What is the most distinguishing characteristic of muscle tissue?
36)
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
37)
Myoglobin ________.
37)
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
38)
Fatigued muscle cells that recover rapidly are the products of ________.
38)
A)
slow exercise of short duration
B)
intense exercise of short duration
C)
intense exercise of long duration
D)
slow exercise of long duration
39)
Which of the following is the correct sequence of events for muscle contractions?
39)
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
40)
Muscle tissue has all of the following properties except ________.
40)
A)
secretion
B)
contractility
C)
excitability
D)
extensibility
41)
What part of the sarcolemma contains acetylcholine receptors?
41)
A)
end of the muscle fiber
B)
motor end plate
C)
part adjacent to another muscle cell
D)
any part of the sarcolemma
42)
Creatine phosphate functions in the muscle cell by ________.
42)
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
43)
What does excess postexercise oxygen consumption represent?
43)
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
44)
What is the functional unit of a skeletal muscle called?
44)
A)
a myofibril
B)
a sarcomere
C)
the sarcoplasmic reticulum
D)
a myofilament
45)
Which of the choices below does not describe how excess postexercise oxygen consumption
(oxygen deficit) restores metabolic conditions?
45)
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
46)
Which of the following statements is true?
46)
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.
47)
The mechanism of contraction in smooth muscle is different from skeletal muscle in that ________.
47)
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
48)
Which of the following would be recruited later in muscle stimulation when contractile strength
increases?
48)
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
49)
Which of the following is true about smooth muscle?
49)
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.
50)
The strongest muscle contractions are normally achieved by ________.
50)
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
51)
What is the role of tropomyosin in skeletal muscles?
51)
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.
52)
The sliding filament model of contraction involves ________.
52)
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
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
53)
Define physiologic muscle fatigue.
53)
54)
What are caveolae?
54)
55)
In the synaptic cleft of a neuromuscular junction, an enzyme called ________ is always
present.
55)
Figure 9.2
Using Figure 9.2, match the following:
56)
H zone.
56)
57)
What ultimately stops muscle stimulation when the motor neuron ceases firing?
57)
Figure 9.2
Using Figure 9.2, match the following:
58)
M line.
58)
Figure 9.1
Using Figure 9.1, match the following:
59)
Bundle of muscle cells surrounded by a perimysium
59)
60)
The time in which cross bridges are active is called the period of ________.
60)
61)
What is muscle tension?
61)
62)
What are the parts of the skeletal muscle triad and what are their functions?
62)
63)
The end of the muscle that typically moves when a muscle contracts is called the ________.
63)
Figure 9.2
Using Figure 9.2, match the following:
64)
Z disc.
64)
65)
A smooth, sustained contraction from rapid stimulation is called ________.
65)
