Mace - Muscle Flashcards
1
Q
what are the 3 types of muscle tissue
A
skeletal
cardiac
smooth
2
Q
what causes skeletal muscle to look striated
A
alternating light and dark bands
3
Q
skeletal muscle is __ and
under __ control
A
voluntary
conscious
4
Q
describe the structure of skeletal muscle fibers (cells)
A
long, unbranched, cylindrical
4
Q
describe the arrangement of skeletal muscle tissue
A
parallel bundles that run the length of the entire muscle
5
Q
skeletal muscle is __nucleated,
which are positioned __ to the cell membrane
A
multi
adjacent
6
Q
where is skeletal muscle found (3)
A
bone
skin
surrounding distal ends of digestive and urinary tracts as sphincters
7
Q
the contraction of skeletal muscle tissue causes (3)
A
bone movement
facial expression
defection or urination
8
Q
describe the structure of cardiac muscle tissue
A
short, branched cardiac muscle cells
9
Q
describe the nuclei of cardiac muscle tissue
A
one or two centrally located
mitochondria-rich
10
Q
cardiac muscle tissue is __
and __,
with cells that are
__ in one direction
A
striated
branched
closely packed
11
Q
what are intercalated discs
A
junction between cells
12
Q
what is the fxn of intercalated discs (2)
A
strengthens attachments between cells
promotes rapid conduction of electrical activity thru cardiac cells
13
Q
is cardiac muscle voluntary or involuntary
A
involuntary
14
Q
what is meant by syncytium of cardiac muscle tissue
A
its structure allows for rapid coordination of muscles along the entire length
15
Q
describe the structure of smooth muscle tissue cells
A
spindle shaped
16
Q
describe the arrangement of smooth muscle tissue cells (3)
A
short
closely packed in one direction
branched
17
Q
smooth muscle tissue cells have __ nuclei, which is
__ located
A
one
centrally
18
Q
does smooth muscle tissue have striations
A
no
19
Q
where is smooth muscle tissue found
A
walls of digestive, respiratory, urinary tracts
erector pili of skin
surrounding bv
20
Q
where in the respiratory system is smooth muscle tissue found
A
sphincters
21
Q
smooth muscle tissue is under __ control
A
involuntary
22
Q
what are the functions of smooth muscle tissue (5)
A
moves substances along internal passages (peristalsis)
erects hairs
controls blood flow and blood pressure
regulates airflow in lungs
controls urination and defecation
23
Q
what are the fxns of skeletal muscle tissue (5)
A
body movement
maintenance of posture
protection and support
storage and movement of materials
heat production
24
how is skeletal muscle involved in protection and support
muscles along the walls of the abd and pelvic cavities protect internal organs and maintain position
25
how is skeletal muscle involved in storage and movement of materials
contracts and relaxes sphincters
26
how does skeletal muscle produce heat
byproduct of muscle contraction
27
what is the main source of heat produced w.in the body
byproduct of muscle contraction
28
muscle cells are organized into bundles called
fascicles
29
fascicles extend from
tendon to tendon
30
each muscle contains (3)
CT
blood vessels
nerves
31
what are the 3 concentric layers of CT in skeletal muscle
epimysium
perimysium
endomysium
32
what is the fxn of skeletal muscle (3)
protection
sites for bv and nerve distribution
means of attachment to skeleton or other structures
33
which layer of skeletal muscle tissue is a single layer of dense irregular CT that surrounds the entire muscle
epimysium
34
which layer of skeletal muscle tissue is dense irregular CT surrounding the fascicles
perimysium
35
which layer of skeletal muscle tissue contains extensive bv and nerve supplying fibers
perimysium
36
which layer of skeletal muscle tissue is made of areolar CT that surrounds and electrically insulates each muscle fibers
endomysium
37
what are tendons composed of
dense regular CT
38
tendons are __ like structures
formed by __ connective tissue layers
cord
3
39
what is the fxn of tendons (2)
attach muscle to bone
attach muscle to skin or another structure
40
aponeurosis is a type of \_\_
with a wide area of attachment
tendon
41
aponeurosis is a thin, flattened sheet formed from __ connective tissue layers
3
42
what is the fxn of the aponeurosis
holds muscles together for functional enhancement
43
deep fascia is an additional sheet of
dense irregular CT
44
where is deep fascia located
external to the epimysium
45
what is the fxn of deep fascia (4)
separates individual muscles
binds together muscles w. similar fxns
contains nerves, bv, lymph vessels
fills spaces btw muscles
46
what is fascia made of
dense irregular CT
47
what is the fxn of fascia
separates neighboring muscles. (organs) or muscle groups from one another
separates muscles from hypodermis
makes up the inter muscular septum
48
the end, peri, and epimysium become the
tendons
49
when a muscle cell contracts, the pull on the \_\_, which pull on the
\_\_ to move bones that are attached to the muscle
endo, peri, and epimysium
tendons
50
skeletal muscle cells are the dominant cell in \_\_
and contain __ proteins
muscle
contractile
51
what is the fxn of satellite cells
differentiate to repair injured muscle cells
52
do satellite cells have contractile proteins
no
53
what is the sarcolemma
membrane of the skeletal muscle cell
54
what happens at the sarcolemma during muscle contraction
explosive release of calcium
55
release of calcium from the sarcolemma continues as long as\_\_ is present
ATP
56
T-tubues (transverse tubules) are deep invaginations of \_\_
sarcolemma
57
what is the fxn of the sarcolemma
transmits nerve impulses from sarcolemma inward
58
what is the sarcoplasmic reticulum
a tubular network around contractile proteins
59
describe the structure of the sarcoplasmic reticulum
modified smooth endoplasmic reticulum
60
what is the fxn of the sarcoplasmic reticulum
stores calcium to release into sarcoplasm during muscle contraction
61
what are the dilated ends of the sarcoplasmic reticulum
terminal cisternae
62
what is the fxn of terminal cisternae
reservoirs for calcium ions
63
terminal cisternae combine w. T-tubules to form
triads
64
myoglobin is a __ protein
found in the \_\_
globular
sarcoplasm
65
what is the fxn of myoglobin
allows muscle cells to store O2
66
the redder the muscle, the more __ it has
myoglobin
67
where are myofibrils located
sarcoplasm
68
what are the special contractile proteins of skeletal muscle
myofibrils
69
myofibrils account for \_% of skeletal muscle volume
80
70
what are myofibrils composed of
a bundle of thick and thin myofilaments
71
what is responsible for muscle contraction
interactions between thick and thin filaments
72
muscles shorten along their
fiber axis
73
thick filaments are assembled from bundles of protein molecules called
myosin
74
each myosin has two \_\_,
and each strand has a globular \_\_
and a elongated \_\_
intertwined strands
head
tail
75
the tails of myosin point
toward the center of thick filaments
76
the heads of myosin point
toward the edges of thick filaments
77
the head of myosin has a binding site for (2)
actin
ATP
78
actin is found on the
thin filament
79
the thin filament is composed of (3)
actin
tropomyosin
troponin
80
what is the primary component of the thin filament
actin
81
describe the structure of actin in the thin filament
two strands twisted around each other
82
each strand of actin is composed of many __ molecules
called \_\_
spherical
G-actin (globular actin)
83
each strand of actin is composed of many __ molecules
called \_\_
spherical
G-actin (globular actin)
84
where is the myosin binding site located
G-actin
85
describe the structure of tropomyosin
twisted string-like
86
what is the fxn of tropomyosin
covers myosin binding site in a non contracting muscle
87
troponin is a __ protein attached to
\_\_
globular
tropomyosin
88
what is the fxn of troponin
binding site for Ca2+
89
what is the sarcomere made of
repeating functional units of myofilaments
90
what separates sarcomeres from one another
z discs
91
what separates sarcomeres from one another
z discs
92
describe the structure and location of z-discs
specialized proteins
perpendicular to myofilaments
92
describe the structure and location of z-discs
specialized proteins
perpendicular to myofilaments
93
what is the fxn of z-discs
anchors for thin filaments
94
I bands contain only
thin filaments
95
I bands appear __ under a microscope
and disappear during \_\_
light
maxima muscle contraction
96
what is the central region of the sarcomere
A band
96
what is the central region of the sarcomere
A band
97
the A band contains the entire \_\_
and partially overlapping \_\_
thick filament
thin filaments
98
how does the A band appear under a microscope
dark
99
what is the central portion of the A band
H zone
100
the H zone contains only
thick filaments
101
the H zone disappears during
maximal muscle contraction
102
what is the protein meshwork structure at the center of the H zone
M line
103
what is the fxn of the M line
attachment site for thick filaments
104
zones of the sarcomere
105
understand the zones of the sarcomere during muscle contraction
106
where are neuromuscular junctions located
where somatomotor neuron innervates muscle
107
how many neuromuscular junctions does each cell have
1
108
what are the components of the neuromuscular junction (3)
synaptic knob
motor end plate
synaptic cleft
109
what is the expanded tip of the axon at the neuromuscular junction
synaptic knob
110
what is found inside the synaptic knob
synaptic vesicles
111
synaptic vesicles are small \_\_
filled with \_\_
membrane sacs
acetylcholine (Ach)
112
the synaptic knob has __ in the plasma membrane
calcium pumps
113
the calcium pumps on the synaptic knob plasma membrane establish the calcium \_\_,
wich more calcium __ the neuron
establish calcium gradient
outside
114
the synaptic knob also has **\_\_** calcium channels, which are opened by
\_\_ signals
voltage gated
nerve
115
the synaptic knob has calcium \_\_
and voltage gated calcium \_\_
pumps
channels
116
the calcium pump pumps calcium __ its concentration gradient to move calcium
\_\_
against
from the inside of the synaptic vesicle
117
how does Ach leave the synaptic vesicle
exocytosis
118
what is the specialized region of the sarcolemma covered by the synaptic knob
motor end plate
119
what type of receptor does the motor end plate have
Ach
120
the synaptic cleft is a narrow __ filled space
that separates the \_\_
and the \_\_
fluid
synaptic knob
motor end plate
121
the synaptic cleft contains __ enzyme that breaks down
\_\_ molecules after their release into the synaptic cleft
acetylcholinesterase
Ach
122
what is the 1st event of skeletal muscle contraction
1. skeletal muscle excitation
123
what is the 2nd event of skeletal muscle contraction
excitation-contraction coupling
124
what is the 3rd event in skeletal muscle contraction
binding of Ca2+ and cross-bridge cycling
124
what is the 3rd event in skeletal muscle contraction
binding of Ca2+ and cross-bridge cycling
125
what are the 3 steps in skeletal muscle contraction
1. excitation of a skeletal muscle
2. excitation-contraction coupling
3. binding of Ca2+ and cross-bridge cycling
126
what are the steps in skeletal muscle relaxation
1. hydrolysis of Ach at receptor (acetylcholinesterase) → closure of receptor channel
2. no further ap generated
3. **closure of Ca2+ channels in SR**
4. released Ca2+ continuously returned by Ca2+ pumps back into SR
5. return of troponin to its original shape
6. tropomyosin now moving over myosin binding sites on actin → prevents cross-bridge formation
7. returns to original relaxed position thru natural elasticity of muscle fiber
127
how does dantrolene work and what is it used for
interferes w. Ca2+ release at SR
spasticity in cerebral palsy, stroke, MS
128
how does succinylcholine (ancetine) work
nmj blocking (numbd)
binds Ach receptor at motor endplate insensitive to AchE → maintained depolarization of motor endplate → flaccid skeletal muscle paralysis
129
what is succinylcholine (anectine) used for
endotracheal intubation
surgery
mechanical ventilation
130
does succinylcholine have pain relieving properties
no!
131
what are the 3 ways ATP is supplied for muscle contraction
immediate
short term
long term
132
immediate supply of ATP is called the
phosphagen system, 5-6s
133
the immediate/phosphagen system 5-6 is \_\_
and uses (3)
anaerobic
available ATP, myokinase, creatinine phosphate
134
the immediate/phosphagen system 5-6 is \_\_
and uses (3)
anaerobic
available ATP, myokinase, creatinine phosphate
135
short-term supply of ATP uses \_\_
and is __ cellular respiration
glycolysis
anaerobic
136
short term supply of ATP lasts ~
50-60 s
137
in short term supply of ATP, __ is stored inside the muscle fiber or delivered by the blood
glucose
138
in short term supply of ATP, breakdown of 1 glucose molecule results in production of
2 ATP
2 pyruvate
NADH
139
efforts lasting 50-60 s use both \_\_
and __ and result in a
\_\_ debt
phosphagen system
glycolysis
oxygen
140
long term ATP supply uses \_\_
and is __ cellular respiration
oxidative phosphorylation
aerobic
141
long term supply of ATP is used for efforts lasting
greater than 5-6 min
142
long term supply of ATP uses __ produced in glycolysis,
and occurs in the
pyruvate
mitochondria
143
long term supply of ATP requires \_\_
and produces __ ATP per glucose
oxygen
34
144
skeletal muscle fiber is classified by (2)
type of contraction
energy source
144
skeletal muscle fiber is classified by (2)
type of contraction
energy source
145
what are the classifications of types of skeletal muscle contraction
power
speed
duration of contraction
146
the power of muscle contraction is primarily based on
muscle fiber diameter
147
the speed of muscle contraction is determined by
slow or fast twitch muscle fibers
148
the duration of muscle contraction is determined by
conduction/EC-coupling speed
149
what is the energy source of muscle contraction
glycolysis OR oxidative phosphorylation
150
oxidative muscle fibers use __ metabolism and are used for
\_\_ activity
aerobic
high endurance
151
oxidative fiber structure consists of (3)
extensive capillaries
high # of mitochondria
high concentration of myoglobin
152
what is the source of oxygen for oxidative fibers
myoglobin
153
glycolic fibers use __ metabolism and are
easily \_\_
anaerobic
fatigued
154
glycolytic fibers have large reserves of
glycogen
155
what are the 2 types of muscle contraction
isometric
isotonic
156
what type of muscle contraction is insufficient to overcome the load and shows no movement at the joint
isometric
157
during isometric contraction, the muscle __ while
tension \_\_, but the
angle of the joint \_\_
shortens
increases
does not change
158
what type of muscle contraction is greater than the load
isotonic
159
during isotonic contraction, __ remains constant,
but \_\_
and __ change
tension
length and joint angle
160
what is concentric contraction
isotonic contraction w. muscle length decreasing
161
what is eccentric contraction
isotonic contraction w. muscle length increasing
162
what is muscle twitch
single, brief contraction in response to a single stimulation of sufficient intensity (voltage)
163
what is threshold
minimum voltage necessary to activate a muscle → stimulate a contraction
164
what is the latent period
after stimulus is applied, before contraction begins (EPP, CICR, ECC)
165
muscle tension is dependent on (2)
intensity
frequency
166
which motor units are activated at threshold
only the most sensitive
167
what is all or nothing muscle contraction
individual muscle fibers contract (activate) or they do not
168
what determines whether or not a muscle fiber contracts
stimuli
169
the force of muscle contraction is determined by
of muscle fibers activated
170
increased stimulus intensity (voltage) leads to increased \_\_
and increased
\_\_ until max is achieved
of activated motor units
tension
171
muscles can be activated until
maximum muscle tension is reached
172
muscle tension is dependent on (2)
stimulus intensity
frequency of stimulation
173
given sufficient time for relaxation, developed muscle tension will
remain the same for a given stimulus intensity
174
what does treppe describe
given sufficient time for relaxation, as frequency increases (same stimulus intensity), muscle tension increases
175
what 3 factors lead to treppe
1. insufficient time for Ca2+ removal by Ca2+ pumps
2. more cross bridges form w. additional stimulation
3. increased muscle heat → increased efficiency of molecular interactions
176
what is wave/temporal summation
as frequency continues to increased (same stimulus intensity), there is insufficient time for Ca2+ removal, more cross bridge formation, and increased muscle heat BUT time is NOT sufficient for complete relaxation
177
do tetany and rigor have the same mechanism as wave/temporal summation
no
178
what are the similarities btw cardiac muscle and skeletal muscle (3)
striated
t-tubules
CICR
179
what are the dissimilarities btw skeletal m and cardiac m (4)
cardiac m has:
1. less extensive SR network w. no terminal cisternae
2. almost entirely aerobic
3. optimal thick/thin filament overlap during stretch
4. intercalated discs
180
what % of cardiac m volume is mitochondria
25%
181
what are 4 fxn's of intercalated discs
1. increased stability
2. increased communication/conduction btw cadiomyocytes
3. desmosomes at intercalated discs anchor cardiomyocytes together
4. gap junctions allow for low resistance conduction btw cardiomyocytes
182
what structures prevent the heart from tearing
desmosomes
183
what structure allows for syncytium
gap junctions
184
where is smooth muscle located (6)
blood vessels
respiratory
digestive
urinary
reproductive
specialized: iris of eye, erector pili
185
is smooth m smaller or larger than skeletal m
smaller
186
smooth m has only the __ layer,
composed of \_\_
endomysium
areolar CT
187
smooth muscles has __ ends
no \_\_,
and limited \_\_
tapered
t-tubules
SR
188
how is Ca2+ transport at the SR of smooth m regulated (3)
v-gated
chem-gated
modality gated
189
what are 3 examples of modality gated Ca2+ regulation at the SR
thermal
stretch hyperglycemia
190
what are the 3 anchoring proteins in smooth m
cytoskeleton
dense bodies
dense plaques
191
the cytoskeleton of smooth m is a network of __ filaments
intermediate
192
dense bodies are the anchoring sites for __ filaments,
similar to __ disks in skeletal m
thin
Z
193
what is the fxn of dense plaques
bind the intermediate filaments to the SL
194
what is the contractile mechanism of smooth m
contractile proteins
195
where are contractile proteins of smooth m located
between dense bodies along the cytoskeleton
196
contractile proteins of smooth m do not have \_\_
or \_\_
sarcomeres
z-discs
197
describe the arrangement of the contractile mechanism of smooth m
spiral/longitudinal arrangement
198
the spiral/longitudinal arrangement of the contractile mechanism of smooth muscle allows for
contraction in multiple directions → twisting
199
smooth muscle contraction
200
thick filaments of contractile mechanisms of smooth m have __ along the entire axis
and a __ mechanism that allows
for \_\_
myosin
latch
the muscle to stay shortened w.o using additional ATP
201
the thin filaments of smooth muscle have __ (2)
but no \_\_
actin, tropomyosin
troponin
202
since the contractile mechanism of smooth muscle does not have troponin, they do not have a
Ca2+ binding site
203
without a Ca2+ binding site on the contractile mechanism of smooth m, what brings the myosin hard into binding conformation w. actin
the myosin head itself is phosphorylated
204
what completes the phosphorylation of the myosin head in the contractile mechanism of smooth muscle
calmodulin
myosin light chain kinase (MLCK)
205
relaxation of smooth muscle occurs via
breakdown of MLCK by myosin light chain phosphorylase
206
concentric and eccentric m contractions are subtypes of
isotonic contraction
207
example of isotonic contraction
10 lb bag of potatoes requires 11 lb of tone to lift → once tension exceeds 10 lb, muscle contracts
208
ex of isometric contraction
1,000 lb piano requires 1,001 lb to lift → tension builds but will never reach 1,001 lb → m never contracts
209
factors that increase force of contraction
**increased:**
fiber diameter
fiber length
of active fibers
frequency of stimulation
**decreased:**
velocity → slower contraction = stronger contraction
210
what is the one decreased factor that increases force of contractin
velocity → slower contraction = stronger contraction
211
high-frequency delivery of electrical stimuli causes
tetany
212
what is rigor
disappearance of ATP from the muscle → actin/myosin filaments unable to detach → filaments become permanently attached
213
which type of m fiber has the smallest diameter
slow
214
which type of m fiber is the reddest
slow
215
which type of m fiber is the shortest
FG
216
which type of muscle fiber is found in upper limbs
FG
217
which type of m fiber maintains posture
slow
218
oxidative m fibers have high amounts of (3)
mitochondria
capillaries
myoglobins
219
smooth m fibers does not have __ (4)
and have limited \_\_
**do not have:**
t-tubules
sarcomere
z disk
troponin
**limited:**
sarcoplasmic reticulum
220
what facilitates contraction in multiple directions in smooth m
spiral/longitudinal arrangement
221
smooth m uses __ for contraction instead of sarcomeres and z disks
contractile proteins
222
what is the latch mechanism of smooth m
dephosphorylated myosin remains attached to actin → prolonged tonic contraction for hours w. little use of energy → long-term maintenance of tone w.o fatigue
223
what is an example of the latch system of smooth m
urinary bladder full of urine
224
