Chapter 10 Muscle Tissue Flashcards
1
Q
Muscle tissue, one of the four basic tissue groups, consists chiefly of cells that are highly specialized for
A
contraction
2
Q
Which of the following is a recognized function of skeletal muscle?
A) produce movement B) maintain posture C) maintain body temperature D) guard body entrances and exits E) All of the answers are correct.
A
produce movement, maintain posture, maintain body temperature, guard body entrances and exits
3
Q
At each end of the muscle, the collagen fibers of the epimysium, perimysium, and endomysium, come together to form a
A
tendon
4
Q
The dense layer of connective tissue that surrounds an entire skeletal muscle is the
A
epimysium
5
Q
Nerves and blood vessels that service a muscle fiber are located in the connective tissues of its
A
endomysium
6
Q
A fascicle is a
A
group of muscle fibers that are encased in the perimysium
7
Q
The delicate connective tissue that surrounds the skeletal muscle fibers and ties adjacent muscle fibers together is the
A
endomysium
8
Q
The bundle of collagen fibers at the end of a skeletal muscle that attaches the muscle to bone is called a(n)
A
tendon
9
Q
Put the following structures in order from superficial to deep.
- muscle fiber
- perimysium
- myofibril
- fascicle
- endomysium
- epimysium
A
6, 2, 4, 5, 1, 3
epimysium, perimysium, fascicle, endomysium, muscle fiber, myofibril
10
Q
A(n) ________ can be described as a broad tendinous sheet.
A
aponeurosis
11
Q
Interactions between actin and myosin filaments of the sarcomere are responsible for
A
muscle contraction
12
Q
In a sarcomere, the central portion of thick filaments are linked laterally by proteins of the
A
M line
13
Q
The advantage of having many nuclei in a skeletal muscle fiber is the ability to
A
produce large amounts of muscle proteins
14
Q
Skeletal muscle fibers are formed from embryonic cells called
A
myoblasts
15
Q
The repeating unit of a skeletal muscle fiber is the
A
sarcomere
16
Q
The plasma membrane of a skeletal muscle fiber is called the
A
sarcolemma
17
Q
Which of the following best describes the term sarcomere?
A) protein that accounts for elasticity of resting muscle B) repeating unit of striated myofibrils C) storage site for calcium ions D) thin filaments are anchored here E) largely made of myosin molecules
A
B) repeating unit of striated myofibrils
18
Q
Muscle fibers differ from “typical cells” in that muscle fibers
A
have many nuclei
19
Q
Which of the following best describes the term sarcoplasmic reticulum?
A) protein that accounts for elasticity of resting muscle
B) repeating unit of striated myofibrils
C) storage and release site for calcium ions
D) thin filaments are anchored here
E) largely made of myosin molecules
A
C) storage and release site for calcium ions
20
Q
Which of the following best describes the term Z line?
A) protein that accounts for elasticity of resting muscle B) repeating unit of striated myofibrils C) storage site for calcium ions D) thin filaments are anchored here E) largely made of myosin molecules
A
D) thin filaments are anchored here
21
Q
The region of the sarcomere containing the thick filaments is the
A
A band
22
Q
The skeletal muscle complex known as the triad consists of
A
a transverse tubule and two terminal cisternae
23
Q
The area in the center of the A band that contains no thin filaments is the
A
H band
24
Q
At rest, the tropomyosin molecule is held in place by
A
troponin molecules
25
Each thin filament consists of
two actin protein strands coiled helically around each other
26
The region of the sarcomere that always contains thin filaments is the
I band
27
Which skeletal muscle fiber type—slow or fast—contains more mitochondria?
slow
28
What happens to sarcomere length if the zone of overlap is decreased?
sarcomere length increases
29
Match the level of organization with the structure that surrounds it:
Level of organization: skeletal muscle, muscle fascicle, muscle fiber, myofibril
Surrounding structure: endomysium, epimysium, perimysium, sarcoplasmic reticulum.
skeletal muscle—epimysium; muscle fascicle—perimysium; muscle fiber—endomysium; myofibril— sarcoplasmic reticulum
30
The terminal cisternae that form a triad along with a T tubule are part of what organelle?
sarcoplasmic reticulum
31
Which of the following is true about the difference between cardiac muscle cells and skeletal muscle cells?
A) Cardiac muscle cells does not have striations like skeletal muscle cells.
B) Cardiac muscle cells does not have t-tubules.
C) Cardiac muscle cells does not have sarcomeres.
D) Cardiac muscle cells have intercalated discs where skeletal muscle cells do not.
E) Cardiac muscle cells have more nuclei in them than skeletal muscle cells.
D) Cardiac muscle cells have intercalated discs where skeletal muscle cells do not.
32
Which of the following is not a function of smooth muscle tissue?
A) altering the diameter of the respiratory passageways
B) elevating hairs on the arm
C) forcing blood from the heart into the major arteries
D) moving food materials along the digestive tract
E) forcing urine out of the urinary tract
C) forcing blood from the heart into the major arteries
33
Which of the following is not characteristic of smooth muscle?
A) The striations are due to the orderly arrangement of actin and myosin.
B) Neurons that innervate smooth muscles are under involuntary control.
C) Smooth muscle cells are uninucleate.
D) Smooth muscles do not contain sarcomeres.
E) The thin filaments of smooth muscle fibers are attached to dense bodies.
A) The striations are due to the orderly arrangement of actin and myosin
34
The ability of smooth muscle to function over a wide range of lengths is called
plasticity
35
Which of the following is not an effect of aging on the muscular system?
```
A) hypertrophy
B) smaller muscle fibers
C) decreased recovery from muscle injuries
D) exercise tolerance decreases
E) muscles become less elastic
```
A) hypertrophy
36
Which of the following types of muscle fibers are best adapted for prolonged contraction such as standing all day?
slow fibers
37
Large-diameter, densely packed myofibrils, large glycogen reserves, and few mitochondria are characteristics of
fast fibers
38
Which of the following statements is/are false regarding human muscles?
A) Most have both slow and fast fibers.
B) Slow fibers are abundant in the muscles of the hand.
C) Eye muscles are composed entirely of fast fibers.
D) Slow fibers are abundant in the back muscles.
E) All of the answers are correct; none of them are true regarding human muscles.
B) Slow fibers are abundant in the muscles of the hand.
39
Muscles that move the eyeball have ________ fibers.
fast
40
Fast fibers
have low resistance to fatigue and quick twitches
41
The type of muscle fiber that is most resistant to fatigue is the ________ fiber.
slow
42
Heat energy gained from muscle contraction is released by the ________ system.
integumentary
43
How would an elevated level of thyroid hormone in the body affect skeletal muscles?
It would stimulate energy use and heat production.
44
Which of the following hormones directly stimulates growth of muscle tissue, leading to increased muscle mass?
testosterone
45
During the recovery period following exercise, all of the following are true except
A) lactic acid is removed from muscle cells.
B) the muscle actively produces ATP.
C) muscle fibers are unable to contract.
D) oxygen is consumed at above the resting rate.
E) heat is generated.
C) muscle fibers are unable to contract.
46
Aerobic metabolism normally provides ________ percent of the ATP demands of a resting muscle cell.
95
47
During anaerobic glycolysis,
ATP is produced, pyruvic acid is produced, oxygen is not consumed, and carbohydrate is metabolized
48
Creatine phosphate
acts as an energy reserve in muscle tissue
49
A resting muscle generates most of its ATP by
aerobic metabolism of fatty acids
50
Which of the following allows muscles to return to their original shape during relaxation?
gravity, opposing muscle contractions, and elastic forces
51
The type of contraction where the tension is less than the load is called
isotonic eccentric contraction
52
The type of contraction where the tension exceeds the load is called
isotonic concentric contraction
53
Identify the incorrect statement about a single motor unit.
A) The more neurons involved, the more powerful the contraction.
B) The smaller the number of muscle fibers, the more precise the movement.
C) Fine motor skills depend on the development of small motor units.
D) Some motor units include as many as 2000 muscle fibers.
E) Muscle fibers of one motor unit intermingle with the fibers of another motor unit.
A) The more neurons involved, the more powerful the contraction.
54
In an isotonic contraction,
muscle tension exceeds the load and the muscle lifts the load.
55
In which of the following would the motor units have the fewest muscle fibers?
```
A) muscles of the neck
B) postural muscles of the back
C) muscles that control the eyes
D) thigh muscles
E) calf muscles
```
C) muscles that control the eyes
56
You try to pick up an object and discover that it is much heavier than you expected. Which process must occur in the muscle to increase tension so you can pick up the object?
recruitment
57
A weight-lifter strains to lift a heavy weight and there is no movement of the person's arms holding on to the weight. This type of contraction is called a(n) ________ contraction.
isometric
58
The type of contraction in which the muscle fibers do not shorten is called
isometric
59
The increase in muscle tension that is produced by increasing the number of active motor units is called
recruitment
60
A single motor neuron together with all the muscle fibers it innervates is called a(n)
motor unit
61
Detachment of myosin cross-bridges occurs during the
relaxation phase
62
The point in a muscle twitch when the troponin is bound to calcium is called the
contraction phase
63
During the time when the action potential moves through the sarcolemma a muscle twitch is in
latent period
64
A muscle produces its highest tension when in complete
tetanus
65
A single contraction-relaxation cycle in a muscle fiber produces a(n)
twitch
66
https://o.quizlet.com/LFA9YExIKeG8Af6NNNYPPg.jpg
| What is the contraction in graph (d) called?
complete tetanus
67
Why is there partial relaxation in graph (c)?
Nerve stimulation frequency is below maximum.
68
To produce a contraction similar to the one in graph (b), the muscle
must be stimulated again before it has relaxed from the previous stimulation
69
What is thought to happen in a muscle during the treppe response?
There is a gradual increase in calcium ion concentration in the sarcoplasm.
70
What is the contraction called that has short, gradually increasing waves? (graph a)
treppe
71
If a second stimulus arrives before the relaxation phase has ended, a second, more powerful contraction occurs. This addition of one twitch to another is called
wave summation
72
A muscle producing almost peak tension during rapid cycles of contraction and relaxation is said to be in
incomplete tetanus
73
When a muscle is stimulated repeatedly at a high rate, the amount of tension gradually increases to a steady maximum tension. This state of maximum tension is called
complete tetanus
74
The rapid rise and fall in force produced by a muscle fiber after a single action potential is a(n)
twitch
75
Put the following events of the contraction cycle in the order in which they occur.
1. Cross-bridge detachment
2. Cross-bridge formation
3. Active site exposure
4. Myosin reactivation
5. Calcium ions bind troponin
6. Myosin head pivoting
5,3,2,6,1,4
Calcium ions bind troponin, active site exposure, cross-bridge formation, myosin head pivoting, cross-bridge detachment, and myosin reactivation
76
Put the following events of the neuromuscular junction in the order in which they occur.
1. Action potential is propagated in the sarcolemma.
2. Acetylcholine binds to ligand gated sodium channels.
3. Action potential arrives at the neuromuscular junction.
4. Vesicles full of acetylcholine are stored at the axon terminal.
5. Acetylcholine is released into the synaptic cleft.
4,3,5,2,1
Vesicles full of acetylcholine are stored at the axon terminal, action potential arrives at the neuromuscular junction, acetylcholine is released into the synaptic cleft, acetylcholine binds to ligand gated sodium channels, and action potential is propagated in the sarcolemma
77
Put the following events of excitation-contraction coupling in the order in which they occur.
1. Excitation
2. Sarcomere shortening
3. Generation of muscle tension
4. Neural control
5. Contraction cycle begins
6. Release of calcium ions
4,1,6,5,2,3
Neural control, excitation, release of calcium ions, contraction cycle begins, sarcomere shortening, and generation of muscle tension
78
Which of the following is not true of acetylcholine?
A) It binds to receptor membrane channels.
B) It diffuses across the synaptic cleft.
C) It is stored in the neuron in vesicles.
D) It enters the muscle fiber to release calcium form the sarcoplasmic reticulum.
E) It is digested by acetylcholinesterase.
D) It enters the muscle fiber to release calcium form the sarcoplasmic reticulum.
79
The role of acetylcholinesterase is to
break down acetylcholine into acetate and choline components
80
The sequence of processes that links the action potential to contraction is called
excitation-contraction coupling
81
Cross bridge detachment is caused by ________ binding to the myosin head.
ATP
82
Active sites become exposed when calcium ions bind to
troponin
83
Communication between axons and muscle fibers occurs at specialized synapses called
neuromuscular junctions
84
A patient takes a medication that blocks ACh receptors of skeletal muscle fibers. What is this drug's effect on skeletal muscle contraction?
reduces the muscle's ability for contraction
85
Synaptic vesicles contain neurotransmitters that are released by ________ when the action potential arrives.
exocytosis
86
Which of the following statements about excitation-contraction coupling is incorrect?
A) Calcium ions travel through the transverse tubule.
B) Calcium ion is released from the sarcoplasmic reticulum.
C) Tropomyosin moves to expose myosin binding sites on actin.
D) Troponin binds calcium ion and signals tropomyosin to move.
E) Relaxation requires uptake of calcium ion by the sarcoplasmic reticulum.
A) Calcium ions travel through the transverse tubule.
87
At what point during excitation contraction coupling does exocytosis play a role?
during acetylcholine release from the synaptic terminal
88
The cytoplasm of the neuromuscular terminal contains vesicles filled with molecules of the neurotransmitter
acetylcholine
89
When acetylcholine binds to receptors at the motor end plate, the sarcolemma becomes
more permeable to sodium ions
90
How would the loss of acetylcholinesterase from the motor end plate affect skeletal muscle?
It would cause muscles to stay contracted
91
The following is a list of the events that occur during a muscle contraction. What is the correct sequence of these events?
1. Myosin cross-bridges bind to the actin.
2. The free myosin head splits ATP.
3. Calcium ion is released from the sarcoplasmic reticulum.
4. The myosin head pivots toward the center of the sarcomere.
5. Calcium ion binds to troponin.
6. The myosin head binds an ATP molecule and detaches from the actin.
3, 5, 1, 4, 6, 2
Calcium ion is released from the sarcoplasmic reticulum, calcium ion binds to troponin, myosin cross-bridges bind to the actin, the myosin head pivots toward the center of the sarcomere, the myosin head binds an ATP molecule and detaches from the actin, and the free myosin head splits ATP.
92
Triggering of the muscle action potential occurs after
acetylcholine binds to chemically-gated channels in the motor end plate
93
In a sarcomere, cross-bridge attachment occurs specifically in the
zone of overlap
94
In rigor mortis
A) the myosin heads are attached to actin.
B) ATP is depleted.
C) calcium ions keep binding to troponin.
D) sustained contractions occur.
E) All of the answers are correct.
E) All of the answers are correct.
The myosin heads are attached to actin, ATP is depleted, calcium ions keep binding to troponin, and sustained contractions occur
95
After death, muscle fibers run out of ATP and calcium begins to leak from the sarcoplasmic reticulum into the sarcoplasm. This results in a condition known as
rigor mortis
96
Which of the following become connected by myosin cross-bridges during muscle contraction?
thin filaments and thick filaments
97
The narrow space between the synaptic terminal and the muscle fiber is the
synaptic cleft
98
Each skeletal muscle fiber is controlled by a motor neuron at a single
neuromuscular junction
99
In response to action potentials arriving along the transverse tubules, the sarcoplasmic reticulum releases
calcium ions
100
In the myofibril the thin filament is organized around a rod-like core protein called
nebulin
101
In the myofibril the protein that possesses the active site for myosin heads to bind is called
G actin
102
In the sarcomere the protein that forms two twisted strands around a central rod-like protein is called
actin
103
In the sarcomere which elastic protein attaches the thick filament to the Z line?
titin
104
The region of sarcomere where thin and thick filaments are located is called the
zone of overlap
105
The structural theory that explains how a muscle fiber contracts is called the ________ theory.
sliding filament
106
The complex of a transverse tubule and two adjacent terminal cisternae is known as a
triad
107
Stem cells located between the endomysium and sarcolemma that function in the repair of damaged muscle tissue are called
satellite cells
108
Thick filaments are made of the protein
myosin
109
Thin filaments are mostly made of the protein
actin
110
The protein that regulates muscle contraction by controlling the availability of active sites on actin is called
tropomyosin
111
The protein that is found in the Z line of a sarcomere is called
actinin
112
Physical evidence that supports the sliding filament theory of muscle contraction includes
decreased width of the H band during contraction
113
When calcium ion binds to troponin,
tropomyosin rolls away from the active site
114
The most important factor in decreasing the intracellular concentration of calcium ion after contraction is
active transport of calcium into the sarcoplasmic reticulum
115
The action potential is conducted into a skeletal muscle fiber by
transverse tubules
116
Active sites on the actin become available for binding after
calcium binds to troponin
117
Identify the structure(s) where ATP is consumed.
myofibril and sarcoplasmic reticulum
118
Identify the structure where ATP is produced.
mitochondria
119
Which structure contains the motor end plate?
sacrolemma
120
Where are the myosin molecules located?
thin filament
121
Which structure has pumps to remove calcium ions from the sarcoplasm to produce relaxation?
sarcoplasmic reticulum
122
Where would calcium ions be predominantly found?
terminal cisterna
123
What is released from terminal cisterna?
calcium ions
124
What physiological process occurs in T tubules?
conduction of the action potential into the cell interior
125
What is found in myofibril?
actin, myosin, titin, and tropomyosin
126
Since each myofibril is attached at either end of the muscle fiber, when sarcomeres shorten, the muscle fiber
shortens
127
when a skeletal muscle fiber contracts the
zones of overlap get larger
128
All of the following proteins are part of the thin filaments except
```
A) actin.
B) tropomyosin.
C) troponin.
D) titin.
E) None of the answers is correct; there are no exceptions.
```
titin
129
The series of membranous channels that surround each myofibril is the
sarcoplasmic reticulum
130
The series of membranous channels that surround each myofibril is the
sarcoplasmic reticulum
131
At rest, active sites on the actin are blocked by
Tropomyosin molecules
