Muscle Tissue Flashcards
(143 cards)
1
Q
two different muscle types
A
-striated and smooth
2
Q
muscles cells have what kind of filament?
A
contractile filaments
3
Q
contractile filaments are composed of what two things?
A
- actin
- myosin
4
Q
muscle contraction can be what
A
voluntary or involuntary
5
Q
what conveys neural and vascular elements to muscle cells and acts as a harness for the force of muscle contraction?
A
connective tissue investments
6
Q
what are the three different connective tissue investments important to muscle
A
Epimysium
Perimysium
Endomysium
7
Q
what connective tissue surronds small bundles of muscle?
A
perimysium
8
Q
what are fasciles
A
small bundles of muscle
9
Q
what surrounds the entire muscle and forms aponerouses
A
epimysium
10
Q
what connects skeletal muscle to muscle
A
aponeuroses
11
Q
what connects bone to muscle
A
tendons
12
Q
what surrounds individual muscle cells and is made up of reticular fibers and has an external lamina?
A
endomysium
13
Q
muscle cells are also known as
A
muscle fibers
14
Q
what muscle fibers are slow contracting and do not fatigue easily
A
red fibers
15
Q
what muscle fibers are fast contracting but fatigue easily
A
white fibers
16
Q
3 types of muscle fibers
A
red
white
intermediate
17
Q
what muscles are fast twitch muscles because they have been converted due to endurance training
A
intermediate muscle fibers
18
Q
what do all of the muscle fibers differ from each other on?
A
content of myoglobin , number of mitochondria, rate of contraction,
concentration of various enzymes
19
Q
what is a protein that is similar to hemoglobin because it also binds to oxygen
A
myoglobin
20
Q
what can change a fibers type
A
change in innervation
21
Q
when a red fiber is denervated what happens to its innervatoin
A
it is replaced with white fiber, red fiber will change its characteristics and become
22
Q
muscles cells are formed during development by individual muscle cells called..
A
myoblast
23
Q
what shape do muscle cells have?
A
polygonal
24
Q
how are muscle fibers different from C.T. fibers
A
muscle fibers- are cellular elements
C.T. fiber- are extracellular products of connective tissue cells
25
where are the nuclei located in skeletal muscle?
in the cytoplasm immediatly beneath the plasma membrane
26
what is sarcolemma
plasma membrane of muscle cells
27
shape of skeletal muscle
long and cylindrical
28
what muscle cells are enveloped by an external lamina and reticular fibers
skeletal muscle cells
29
what is the cytoplasm of muscle cells called
sacroplasm
30
skeletal muscle cells posses cylindrical collection of what
myofibrils
31
what are myofibrils made up of
long cylinder bundles of thick and thin myofilaments
32
myofibrils are held in alignment by what intermediate filament?
desmin (vimentin during embrological development)
33
what assists desmin and also tethers Z disks of adjacent myofibrils to one another
plectin
34
what is known to help distribute force for contraction through the whole cell , also protecting integrity of muscle fiber
desmin
35
what is the primary substrate in actively contracting muscles
glucose
36
how much of the dry weight of skeletal and cardiac muscle is glycogen
1%
37
for fast reacting muscles like the legs while running, how is most of the energy provided
by anaerobic glycolysis of stored glycogen
38
how is most of the energy that was used for contraction recovered?
oxidative phosphorylation
39
oxygene that is needed for oxidative phosphorylation comes from where
the oxygen that is bound to myoglobin
40
DRM- desmin-related myopathy is a rare inherited disease in which what happens?
mutation is responsible for the formation of desmin molecules that become desmin aggregates instead of filaments. Since there are no filaments there is disorganization in the cell. So symptoms include, weakness in muscles of the leg, trunk and entire body. Desmin affects cardiac and smooth muscle so DRM is also associated with respiratory problems and heart faliure
41
what is a sacromere
the regular repeating region that is between z disks
42
what is the functional unit of contraction in skeletal muscle
sacromeres
43
SR- sacroplasmic reticulum is what
a modified smooth endoplasmic reticulum that surrounds myofilaments and is the mesh work around each myofibril
44
what encircles the myofibrils at the junction of each A and I band
terminal cisternae
45
how does SR regulate muscle contraction
when it sequesters calcium ions it leads to relaxation and when it release calcium ions it leads to contraction
46
what help provide uniform contraction throughout the muscle cell
triads
47
what are responsible for sarcomere banding patterns and lie parallel to the long axis of myofibril?
thick and thin filaments
48
myofilaments include what two things
thick and thin filaments
49
what are the myoblastlike cells that are left over from embryonic development?
satellite cells
50
what cells are regenerative and fuse together and form skeletal muscle cells when the need arises?
satellite cells
51
what is the size of the synaptic cleft between neurons and muscle cells
20-30nm
52
what is known to break down ACH and bring it back into the presynaptic vesicle until another action potential occurs?
ACH Esterase ( AChE)
53
what are the intermediate filaments that secure adjacent mypofibrils together?
desmin
| vimentin
54
what is the basic contractile unit of a muscle cell?
sarcomere
55
in order to ensure that muscle cells do not become to long or broad, the muscle cell manufactures a protein called?
myostatin
56
what bands usually stain dark
a bands
57
what contains both thick and thin filaments
a bands
58
how many thin filaments surround each thick filament
6
59
what are anisotrpic with polarized light
a bands
60
what are isotropic with polarized light
i bands
61
what appear lightly stained in histological preparations?
i bands
62
anisotropic means
varying in magnitude depending on the direction of measurement
63
what does isotropic mean
having a physical property that s the same value no matter what way you measure it
(not varying in magnitude depending on how you measure it)
64
which bands contain only thin filaments
i bands
65
what are the light regions in a bands
h zones/ bands
66
what consists of only thick filaments
h bands
67
what are the narrow dark regions in the center of h bands at the center of the thick filaments
m lines
68
what are the dense regions that bisect each i band
z discs
69
what is known to anchor z discs together with the help of plectin
desmin
70
parts of the z discs are anchored to parts of the sarcolemma by what
vinculin and dystrophin
71
what are the parts of the z discs that are anchored to the sarcolemma called
costameres
72
actin has a positive and a negative end, what is the positive end connected to? the negative end?
positive- cap Z of Zdisc
negative- tropmodulin
73
what is located at the H band and is the growing end of F-actin
tropomodulin
74
what bind head to tail and are located in the grooves of actin
tropomyosin
75
troponin has three parts what are they
TnT
TnC
TnI
76
what forms the tail of troponin and binds troponin to tropomyosin
TnT
77
what has four binding sites for calcium in troponin
TnC
78
what binds to actin, inhibiting the interaction of myosin and actin
(part of troponin)
TnI
79
what is the long inelastic protein on actin
nebulin
80
how many nebulin molecules wrap around each thin filament and help to anchor it to the z disc?
2 nebulin filaments
81
each nebulin is embedded in what
z disc
82
does nebulin span the entire z dis
no
83
the amino terminal of nebulin ends where
in the a band, at or near the free end of the thin filament
84
what is thought to determine the length od skeletal muscle in association to the thin filament
nebulin
85
what prevents G-actin molecules from growing at the negative end of F-actin?
tropomodulin
86
what is composed of two identically heavy chains and two pairs of light chains
myosinII
87
what is the kind of myosin in skeletal muscle even though there are actually 18 different types?
Myosin II
88
what looks like it has a double headed golf club
myosin
89
the heavy chains of mysoin have what two componenets
long road-like tail and a globular head
90
what do the tails of mysoin function as
self assembly of myosin into thick filaments
91
what do the heads of myosin function as?
as actin binding sites and contraction
92
what is the protein at the M line that cross links adjacent thick filaments to one another, maintaining spatial relations
myomesin
93
what do c proteins do
bind to the thick filaments in the area of the M line
94
what forms the elastic lattice that parallels the thick and thin filaments
titin
95
how many titin anchor a thick filament to the z disck
2
96
titin spans the entire m line and connects to the other half of the sacromere by connecting to what
myomesin
97
in the I band tintin interacts with what at the z disc?
thin filaments
98
within the A band titin interacts with what
C proteins
99
what are the 5 stages of of contraction?
1. attachment
2. release
3. bending
4. force generation
5. reattachment
100
sarcolemma is depolarized where when action potential is present
the neru-muscular junction
101
what conveys the wave of depolarization to the myofibrils
t tubules
102
as long as calcium levels are sufficient and high what?
the contraction will continue
103
during the resting stage, tropomyosin cover the binding sites and what also is responsible for hindering myosin and actin interaction
TnI
104
what is responsible for the confirmation change that breaks the TnI bond
TnC
105
when does relaxation occur
when Calcium contraction in the cytosol is lowered enough that TnC losses its bond to calcium
106
relaxation depends on what
the calcium pump in the SR
107
wat does a motor unit consist of
a neuron and every muscle cell it innervates
108
individual muscle cells obey what rule
all or nothing ( either contract, or dont)
109
picking up a dumbbell is what type of muscle contraction
concentric muscle contraction, sacromeres shorten
110
what kind of contraction takes place when sacromeres do not shorten and the muscle stays the same length
isometric contraction (squeezing a heavy metal ball)
111
muscle spindle functions as?
stretch receptor
112
what is an elongated fusiform sensory organ within the skeletal muscle that functions as a stretch receptor
muscle spindle
113
stretching the muscle also stretches what
muscle spindle
114
what counteracts the affect of muscle spindles (stretching)
golgi tendon organ
115
when is the golgi tendon stimulated?
when the muscle contracts too strenuously which increases tension on the tendon
116
what muscle cells contract spontaneously and have a rhythmic beat?
cardiac muscle cells
117
cardiac muscle have a rhythmic beat that is modified by what
hormonal and neural stimuli (sympathetic and parasympathetic)
118
which cells may branch at the ends to form connections with other cells
cardiac muscle cells
119
which muscle cells do not regenerate
cardiac muscle cells
120
injuries to cardiac causes what kind of repair
formation of fiberous connective tissue by fibroblast (scar tissue)
121
during basal contraction of cardiac muscle, how many binding cites of TnC are occupied
only 50%
122
what has more mitochondria, skeletal or cardiac muscle
cardiac
123
what are the two important things about calcium in regards to the cardiac muscle
1. it leaks into the sarcoplasm at a slow rate during relaxation
2. it comes into the muscle cell from the exteracellular environment through the calcium voltage gated channels.
124
what is present in the atria of the heart
atrial granules
125
what forms end to end attachment between cardiac muscles
intercalated discs
126
what behaves a function syncytium (cells working together)
cardiac muscle
127
at least 90% of energy production in cardiac muscle is produced by what
Aerobic respiration
| requires oxygen to make ATP
128
what are the modified cardiac muscle cells that are in the bundle of his
Purkinje fibers
129
MI (myocardial infarc) is caused by what
prolonged ischemia to heart
130
what are the striated muscle cells that are fusiform and range from 20 um ( small blood vessels)to 500 um (uterus of preggo)
smooth muscle cells
131
what has a centrally located nucleus
smooth muscle cells
132
the heads of myosin in smooth muscle all point in what way
in the same direction
133
for smooth muscle desmin is only found where
in nonvascular smooth muscle cells
134
gap junctions in smooth muscle cells that facilitate the spread of excitement are also called
nexus
135
what is the visceral muscle cell triggered by
stretching of the muscle itself (myogenic)
136
what are smooth muscle cells in the uterus triggered by
oxytocin
137
what triggers smooth muscle cells except in the uterus
epinephrine
138
the autonomic ns innervates what
smooth muscle cells
139
what cells in lactating mammary glands contract in response to oxytocin
myoepithithelial cells
140
myofibrorblast are similar to fibroblast but they have higher amounts of actin and myosin and are capable of
contraction
141
what may contract during wound healing to decrease the size of a wound?
myofibroblast
142
what are known as the pacemaker cells in the heart
autorhytmic cells
143
vascular smooth muscle contraction is triggered by what
nerve impulses
