Skeletal Muscle Flashcards
(123 cards)
1
Q
What are the 3 types of muscle
A
Skeletal, Smooth, and Cardiac
2
Q
Where are the nuclei of skeletal muscle located
A
On the periphery
3
Q
Skeletal muscle have a _______ arrangement
A
Sarcomeric
4
Q
Skeletal muscle has a ________ syncytium
A
Multinucleated
5
Q
Each skeletal muscle fiber is innervated via
A
a single motor neuron
6
Q
Contraction of skeletal muscle is
A
all or none
7
Q
Skeletal muscle contains what troponin
A
C
8
Q
Skeletal muscle cells (fibers) are formed during embryonic development when ?
A
Hundreds of individual mononucleated myoblasts join end-to-end to form a myotube
9
Q
The myotube matures into the what
A
cylindrical myocyte with hundreds of nuclei
10
Q
Each myocyte is about ___ to ___ in diameter
A
50 to 60 micrometers
11
Q
Type I skeletal muscle fibers have intense staining for what
A
oxidative enzymes
12
Q
Type I myofibers are rich in what 3 components
A
NADH transferase, myoglobin, ATPase
13
Q
Type I myofiber types possess many ?
A
Mitochondria
14
Q
Type I myofbers primarily utilize what for energy
A
oxidative phosphorylation
15
Q
Type I myofibers produce ___ and ____ contractions
A
Slow and continuous
16
Q
Type I myofbers are referred to as _____ or ____ fibers
A
dark or red
17
Q
Type IIA myofibers are _________staining for oxidative enzymes
A
intermediate
18
Q
Type IIA myofibers utilize both _____ and _____ respiration for ATP production
A
Aerobic and anaerobic
19
Q
Type IIA contract more rapidly than what type of fibers
A
Type I
20
Q
Type IIA are ____ to fatigue
A
resistant to fatigue
21
Q
Type IIB are _____ staining for oxidative enzymes
A
Light staining
22
Q
Type IIB utilize primarily _____ for ATP production
A
Anaerobic respiration
23
Q
Type IIB contract ________ than type I or Type IIA
A
more rapidly
24
Q
Type IIB fatigue ______?
A
quickly
25
Type IIB are referred to as ___ or ___ fibers
white or light
26
Smooth muscle cells are _____ nucleation
mononucleated
27
Do smooth muscle cells have sarcomeric arrangement
No
28
Smooth muscles are innervated via
The ANS
29
Do smooth muscle cells respond "all or none"
No
30
Smooth muscle cells are connected via?
Gap junctions
31
Cardiac muscles cells show what kind of nucleation
mononucleated
32
What is the position of the nuclei in cardiac muscle cells
centrally positioned
33
In cardiac muscle cells often what
Branch
34
Cardiac muscle cells have a _____ arrangment
Sarcomeric
35
Cardiac Muscle cells communicate via
Gap junction: intercalated discs
36
Are cardiac muscle cells directly innervated
No
37
Muscle is composed of many?
Fasicles
38
A fascicle is a bundle of
Myofibers
39
A myofiber is a bundle of
myofibrils
40
A myofibril is a
linear array of sarcomeres
41
Sarcomeres are made up of what two kinds of filaments
Actin (thin) and myosin (thick)
42
Muscle is covered by a CT sheet called the what
epimysium
43
A fascicle is surrounded by a CT sheet called the what
perimysium
44
The perimysium consists of what
fibroblasts and Type I collagen fibers
45
A myofiber is a muscle cell and is surrounded by a
cell membrane
46
The cell membrane of a muscle cell is called the
sarcolemma
47
what covers the muscle fiber, including the sarcolemma
endomysium
48
The endomysium consists of what
basal lamina and reticular collagen fibers
49
The basal lamina is secreted by
muscle cells
50
What is the function of the basal lamina
anchors muscle fibers to each otherhelps to distribute the force of contraction
51
Sarcomeres are separated from each other by what
z disks
52
The sarcomere shortens during a contraction as evidenced by what
the z disks becoming closer together
53
Myosin is a ____ protein with long tails and ___ heads at one end
dimeric, two
54
Each of the myosin heads has what three characteristics
Actin binding region, ATP-binding region, Light-chain binding region
55
What are the two kinds of light chains
essential and regulatory
56
The light chains are similar to ____ but have lost the ability to bind what
calmodulin, calcium
57
Function of essential light chains
thought to control binding of myosin heads
58
Function of regulatory light chains
maintain the stability of Myosin II, sites for phosphate binding
59
what is the name of a polymer of G actin
F actin
60
F actin's plus end inserts on the
Z-disk
61
F-actin's minus end faces the
H band
62
Each f actin filament consists of
two polymers wound in an alpha-helix configuration
63
name two actin associated molecules in skeletal muscle
Troponin and Tropomyosin
64
Tropomyosin sits where
in the groove between two actin strands of an actin filament
65
Each tropomyosin spans how many actin monomers
7
66
Troponin is a complex of what three moelcules
Troponin I, Troponin C, Troponin T
67
What is the function of Troponin I
Inhibits binding between actin and myosin
68
What is the function of Troponin C
Binds calcium ions
69
What is the function of Troponin T
Binds to tropomyosin
70
____ is the a muscle cells equivalent to endoplasmic reticulum
Sarcoplasmic reticulum
71
Enlargements of the sarcoplasmic reticulum are located next to what
T-Tubules
72
Enlargements of the sarcoplasmic reticulum are refferred to as what
Cisternae
73
Cisternae sequester what
Calcium ions
74
T-Tubules are what
extensions of the sarcolemma that extend down into the sarcoplasm
75
Where are T-Tubules of skeletal muscle located
Where the A and I bands meet
76
T-Tubules provide _______ for myofiber contraction by transferring the AP of the sarcolemma into _____ release from the cisternae
electromechanical coupling, calcium
77
Each _____ molecule extends from the z-band along the length of one thin actin filament
Nebulin
78
_____ acts like a template for the regulation of thin filaments length
Nebulin
79
Each titin molecule extends from
Z-disk to M-line
80
During relaxation titin generates ______ through ____ when the sarcomere is stretched
Passive tension, elastic extension
81
A segment of _____ is closely associated with myosin and maintains the central position of the thick filaments in the sarcomere
Titin
82
Alpha beta- crystallin is what
heat-shock protein that protects desmin from mechanical stress
83
What is dystrophin
one of the proteins that links the alpha-actinin/desmin complex to cytoplasmic side of sarcolemma Anchors actin to the sarcolemmaReinforces sarcolemma during muscle contraction
84
What links dystrophin (intracellular) to laminin-2 (extracellular)
Dystroglycan complex
85
What attaches thin filaments to the z-line
alpha actinin
86
What are the two main function of titin
Provides myosin with elasticitycenters thick filaments in the sarcomere
87
What extends form z-disk to middle of H-band and connects ends of thick filaments to Z-line
Titin
88
Titin has a molecular weight of about
3 million
89
What binds desmin filaments
Plectin
90
What is the framework of desmin filaments which surrounds the Z line and extends into each sarcomere
Desmin intermediate filaments
91
What links myofibrils laterally and to the sarcolemma
Desmin intermediate filaments
92
What extends form z disc to end of actin filaments
nebulin
93
What serves as the template to regulate length of actin filaments
Nebulin
94
What links actin filaments to transmemebrane proteins of muscle cell plasma membranes
Dystrophin
95
Dystrophin is a ______
Calponin
96
Dystrophin, a calponin, links actin filaments ot transmembrane proteins of muscle cell plasma membranes, which then link to the ECM, for what purpose
help maintain cell stability during muscle contraction
97
Muscular dystrophy, is inherited how
X-linked
98
Muscular dystrophy results in what
progressive degeneration of skeletal muscle
99
Dystrophin is absent in patients with what
Duchenne's muscular dystrophy
100
Dystrophin is abnormal in patients with what
Becker's muscular dystrophy
101
An intermediate filament extending from one myofibril to the other and anchored to the sarcolemma, encircles the Z disk of each sarcomere
Desmin
102
Desmin inserts into specialized sarcolemma attachment regions known as what
costameres
103
Desmin facilitates the what
coordinated contraction of individual myofibrils by holding adjacent myofibrils together and linking them to the sarcolemma
104
What links adjacent design filaments to each other
Plectin
105
what is a heat shock protein associated with design, that protects this intermediate filament form street-induced damage
alpha beta- Crystallin
106
Mutations of ____, ___, and _____, cause fragility of the myofibrils and their destruction after continuous stress
Desmin, plectin, alpha beta- crystallin
107
Mutation in _____ causes congenital muscle dystrophy
Laminin 2
108
what links dystrophin to laminin-2
Dystroglycan complex
109
Satellite cells attache to _____ before ____ is laid down
Myotubes, basal lamina
110
Satellite cells function as
Stem cells
111
Are Satellite Cells generally quiescent
Yes
112
Satellite cells can become ______ in times of stress
mitotic
113
Satellite cells give rise to
myogenic precursor cells
114
What is the function of myogenic precursor cells
replace damaged muscle by proliferating, fusing, and differentiating into skeletal muscle fibers.
115
Satellite Cells have a ____ receptor that when acted on by ___ makes them proliferate
C-Met Recepotr, HGF
116
What are the components of the neuromuscular spindle
```
Extrafusal fibers
Intrafusal fibers
Alphamotor neurons
Gamma motor neurons
Primary and secondary afferent fibers
```
117
What are the two kinds of intrafusal fibers
Nuclear bag fibers and Nuclear chain fibers
118
The Nuclear bag region is the ____ region
Sensory region
119
The alpha motor neurons extend to the ____ fibers
extrafusal fibers
120
The gamma motor fibers extend to the
intrafusal fibers.
121
The intrafusal fibers are _____ than the extrafusal muscle fibers
thinner
122
Contraction of ____ muscle fibers, arranged in parallel to the spindle, reduces tension on the muscle spindle, which slacks
extrafusal
123
Activation of gamma motor neurons of the spindle does what
contracts the poles of the spindle thereby pulling the sensory region supplied by sensory nerve fibers.
