BIOL 220: Ch. 10 Flashcards
Terms and concepts from Ch. 10: Muscles
1
Q
three types of muscles in the body
A
skeletal, cardiac, smooth
2
Q
there are over ____ skeletal muscles and together they form the _____
A
700; muscular system
3
Q
properties of muscle tissue (4)
A
excitability
contractility
elasticity
extensibility
4
Q
excitability
A
muscle cells are responsive to input from stimuli
5
Q
contractility
A
stimulation of muscle fiber can lead to contraction and shortening of the muscle fiber
6
Q
elasticity
A
contracted muscle cell can return to resting length when applied tension is removed
7
Q
extensibility
A
ability of a muscle fiber to be stretched beyond its resting length
8
Q
each skeletal muscle is considered an organ because it contains…
A
all four tissue types
9
Q
skeletal muscle is ____ in appearance, _____ in movement, and usually attached to ____
A
striated; voluntary; bones
10
Q
functions of skeletal muscle tissue (5)
A
body movement maintenance of posture temperature regulation storage and movement of materials support
11
Q
fascicles
A
bundles in which muscle fibers are organized to comprise each muscle; covered by perimysium
12
Q
muscle fibers contain…
A
myofibrils
13
Q
myofibrils are composed of…
A
myofilaments
14
Q
each muscle has ____ layers of concentric ____ ____ composed of ____ and _____ fibers
A
three; connective tissue; collagen; elastic
15
Q
CT provides ____, _____, and _____.
A
protection, sites for blood vessel and nerve distribution, a means of attaching the muscle to the skeleton
16
Q
CT components of skeletal muscle from outer to inner (5)
A
superficial fascia deep fascia epimysium perimysium endomysium
17
Q
superficial facia
A
dense irregular connective tissue comprising the epimysium; separates muscle from skin
18
Q
deep fascia
A
dense irregular connective tissue comprising the epimysium; surrounds each muscle and separates muscles from each other
19
Q
epimysium
A
surrounds the entire muscle
20
Q
perimysium
A
dense irregular connective tissue surrounding the fascicles
21
Q
endomysium
A
areolar connective tissue comprising the innermost layer that surrounds and electrically insulates each muscle fiber
22
Q
muscle
A
multiple fascicles housing many many muscle fibers, connective tissue coverings, blood vessels, nerve fibers
23
Q
muscle fibers
A
elongated, multinucleated cylindrical fiber (cell); contains myofibrils, separated from other fibers by delicate layer of areolar connective tissue (endomysium); exhibits striations
24
Q
myofibrils
A
long, cylindrical contractile element within muscle fiber; composed of myofilamants; exhibits striations
25
myofibrils are as long as the ____ _____ itself
muscle fiber
26
myofilaments
short, contractile proteins of two types: thick (myosin) and thin (actin, tropomyosin, and troponin)
27
at the ends of each muscle, all of the CT merge to form a _____
tendon
28
tendon attaches muscle to..
bone, skin, or another muscle
29
tendons are usually cordlike in appearance, but some appear as a flat sheet, termed an _____
aponeurosis
30
Upon conraction of a muscle, one of the articulating bones _____ and the other one does not
moves
31
origin
less moveable point of attachment
32
insertion
more moveable point of attachment
33
sarcolemma
plasma membrane of skeletal muscle fiber
34
sarcoplasm
cytoplasm of a skeletal muscle fiber
35
sarcoplasmic reticulum
smooth ER of skeletal muscle fiber
36
two main structure unique to skeletal muscle
```
transverse tubules (T-tubules
terminal cisternae
```
37
transverse tubulues
deep invaginations of the sarcolemma that extend into the sarcoplasm; orms a network of tubules that enables muscle impulses to spread quickly internally
38
terminal cisternae
blind sacs of the sarcoplasmic reticulum
39
triad
two terminal cisternae + T-tubule
40
myofibrils have the ability to ____, resulting in the contraction of the _____
shorten; muscle fiber
41
myofilaments do not run the entire length of the muscle fiber, but they are organized into...
repetitive groupings
42
two type of myofilaments
thick (myosin)
| thin (actin)
43
thick filaments diameter
11 nm (twice thin)
44
thick filaments are composed of bundled molecules of...
myosin
45
myosin has a _____ and elongated ___
head;tail
46
the heads of myosin form ______ with the thin filaments during contraction
crossbridges
47
thin filaments diameter
5-6 nm
48
thin filaments are comprised of two strands called _____ and ____ twisted around each other
F-actin
| G-actin
49
F-actin is...
filamentous
50
G-actin is..
globular
51
regulatory proteins of thin filament (2)
tropomyosin
| troponin
52
muscle function
metabolic activities; contraction
53
sarcolemma function
surround muscle fiber and regulates entry and exit of materials
54
sarcoplasm function
site of metabolic processes for normal muscle fiber activities
55
sarcoplasmic reticulum function
stores calcium ions needed for muscle contraction
56
terminal cisterna function
site of calcium ion release to promote muscle contraction
57
transverse tubule function
quickly transports impulse from the sarcolemma throughout the entire muscle fiber
58
thick filament function
bind to thin filament and cause contraction
59
thin filament function
thick filaments bind and cause contraction
60
actin and function
double-stranded contractile protein; binding site for myosin to shorten a sarcomere
61
tropomyosin and function
double-stranded regulatory protein; covers the active sites on actin, preventing myosin from binding to actin when muscle fiber is at rest
62
troponin and function
regulatory protein that holds tropomyosin in place and anchors to actin; when calcium ions bind to one of its subunits, troponin changes shape, causing the tropomyosin to move off the actin active site, and this permits myosin binding to actin
63
connectin and function
single molecular filament of a giant protein; plays role in organization of the sarcomere and helps provide passive tension within sarcomere
64
nebulin and function
filament of giant protein; possibly to regulate the length of the thin filament
65
what causes the striated appearance of skeletal muscle?
think and thick filaments
66
dark bands are called ____
A bands
67
A bands contain..
the entire myosin molecule and an overlapping portion of actin
68
light bands are called ____
I bands
69
I bands contain...
thin filaments, but no thick filaments
70
I bands also contain the protein ____
titin
71
H zone (H band)
light, central region of the A band where there are no thin filaments
72
M line
protein meshwork in the H zone that keeps the thick filaments aligned
73
Z disc (Z band)
protein structure in the middle of the I band that serves as the attachment site for one end of the thin filament
74
sarcomere
functional contractile unit in a skeletal muscle fiber; are between two adjacent Z discs
75
myofibrils contain multiple and repeating..
sarcomeres
76
each sarcomere ___ as the muscle fiber contracts
contracts
77
does the sarcomere shorten when the muscle contracts?
yes
78
does the A band shorten when the muscles contracts?
no
79
does the h zone shorten when the muscle contracts?
yes
80
does the m line shorten when the muscle contracts?
no
81
does the I band shorten when the muscle contracts?
yes
82
does the z disc shorten when the muscle contracts?
no
83
muscle fibers shorten by the interaction between thin and thick filaments within each sarcomere, generating..
tension
84
mechanism for contraction is explained by..
sliding filament theory
85
what four things occur during contraction according to the sliding filament theory?
- width of A band remains constant, but H zone disappears
- Z discs in each sarcomere move closer together
- sarcomere narrows in length
I bands narrow
86
_____ of thick and thin filaments never changes, only their _____ changes
length; position
87
neuromuscular junctions
region where the motor neuron comes in close proximity to the muscle fiber
88
muscle contractions begins when a ____ impulse stimulates an _____ in muscle fiber
motor neuron; impulse
89
components of neuromuscular junction (6)
```
synaptic knob
synaptic vesicles
motor end plate
synaptic cleft
Ach receptors
acetylcholinesterase (AChE)
```
90
synaptic knob
expanded tip of an axon
91
synaptic vesicles
membrane sacs filled with acetylcholine (ACh)
92
motor end plate
region of sarcolemma that has folds and indentations to increase the SA covered by the synaptic knob
93
synaptic cleft
narrow sapce separating the synaptic knob and the motor end plate
94
ACh receptors
on the motor end plate; bind ACh
95
acetylcholinesterase (AChE)
enzyme in the synaptic cleft that rapidly breaks down ACh
96
physiology of muscle contraction (6)
1. a nerve impulse causes ACh to be released into the synaptic cleft
2, ACh binds to receptors in the motor end plate intiating a muscle impulse along the sarcolemma and T-tubule membranes
3. spread of the impulse down T-tubules causes calcium to leak out of terminal cisternae
4. calcium ions bind to troponin, causing tropomosyin to uncover active sites on G-actin
5. myosin heads bind to actin and form crossbridges
6. in the presence of ATP, myosin cycles through attachment, pivot, detach, and return events (ATP also necessary for muscle fiber relaxation)
97
motor units
consists of a single motor neuron and the muscle fibers it control
98
a motor unit typically controls only ___ of the muscle fibers in an entire muscle
some
99
size of the motor unit and degree of control provided are ____ related
inversely
100
small motor units provide ___ control
precise
101
all or none principle
obeyed by all muscle fibers, it means that a muscle fiber contracts completely or not at all
102
when a motor unit is stimulated, all muscle fibers under its control will..
contract
103
benefit of having a larger motor unit versus smaller motor units?
it saves space in the brain, needing fewer neurons to accomplish the same job
104
muscle tone
constant tension in a resting muscle
105
motor units are stimulated ____ to avoid fatigue
randomly
106
type of muscle contraction (2)
isometric contraction
| isotonic contraction
107
isometric contraction
length is constant; tension is changing
108
isotonic contraction
tension is constant; length is changing
109
types of isotonic contraction (2)
concentric contraction
| eccentric contraction
110
concentric contraction
muscle is shortening
111
eccentric contraction
muscle is lengthening
112
types of skeletal muscle fibers (3)
1. slow oxidative (SO) fibers
2. fast oxidative (FO) fibers
3. fast glycolytic (FG) fibers
113
slow oxidative fibers and fast oxidative fibers are ____ processes
aerobic
114
fast glycolytic fibers are ____ processes
anaerobic
115
the ratio of fiber types within a muscle determines the ____ and _______ of the contraction
speed, sustainability
116
SO fiber capacity to make ATP
high, aerobic
117
FO fiber capacity to make ATP
moderate, aerobic
118
FG fiber capacity to make ATP
limited, anaerobic
119
concentration of capillaries in SO fibers, FO fibers, and FG fibers
extensive
moderately extensive
sparse
120
color of fibers: SO, FO, FG
dark red; lighter ed; white (pale)
121
amount of myoglobin of fibers: SO, FO, FG
large, medium, small
122
fiber distribution: SO, FO, FG
SO: muscles of trunk, especially postural muscles (contract almost continually)
FO: greatest abundance in muscles of the lower limbs
FG: greatest abundance in muscles of upper limbs
123
skeletal muscles usually contain ____ muscle fiber types
all three
124
a single motor unit controls one muscle fibers of ____ type
the same
125
there are no ____ muscle fibers in muscles that require swift but brief contractions
slow
126
patterns of fascicle arrangements (4)
1. circular
2. parallel
3. convergent
4. pennate
- unipennate
- bipennate
- multipennate
127
circular pattern
fibers arranged concentrically around an opening
| functions as a sphincter to close a passageway or opening
128
circular pattern muscle example
oribularis oris (mouth)
129
parallel pattern
fascicles are parallel to the long axis of the muscle
body of muscle increases in diameter with contraction
high endurance, not very strong
130
parallel pattern muscle example
rectus abdominus (abs)
131
convergent pattern
triangular muscle with common attachment site
directions of pull muscle can be changed
does not pull as hard as equal-sized parallel muscle
132
convergent pattern example
pectoralis major
133
pennate pattern
muscle body has one or more tendons
fascicles oblique angle to tendon
pulls harder than a parallel muscle of equal size
134
unipennate and example
all muscle fibers on the same side of the tendon i.e. extensor digitroum
135
bipennate and example
muscle fibers on both sides of the tendon i.e. rectus femoris
136
multipennate and example
tendon branches within the muscle i.e. deltoid
137
muscle atrophy
wasting of tissue that results in reduction of muscle size, tone, and power; can be caused by lack of stimulation
138
muscle hypertrophy
increase in muscle fiber size (not an increase in number of muscle fibers); results from repetitive stimulation of muscle fibers
139
during muscle hypertrophy, mitochondria ____ in number, therefore the amount of ATP increase
increase
140
during muscle hypertrophy, both myofibrils and myofilaments ___ in number, all resulting in the muscle ____ in size
increase, increase
141
lever
elongated, rigid object that rotate around a fixed point called a fulcrum
142
fulcrum
fixed point on which a lever rotates around
143
rotation occurs when an ___ applied to one point of the lever exceeds a ____ located at some other point
effort; resistance
144
three classes of levers in human body
- first-class lever
- second-class lever
- third-class lever
145
agonist
produces a specific movement when it contracts; also called prime mover
146
antagonist
muscle whose action opposes that of an agonist
147
synergist
muscle that assists the agonist in performing its action
148
criteria of naming skeletal muscles (6)
1. muscle action
2. specific body regions
3. muscle attachments
4. orientation of muscle fibers
5. muscle shape and size
6. muscle heads/tendons of origin
149
muscle action (4)
adduction
abductor
flexor
extensor
150
specific body regions (14)
```
oris
cervicis
brachial
carpi
pollicis
gluteal
femoris
hallucis
anterior
porterior or dorsal/dorsi
superior
inferior
superficialis
profundus
```
151
muscle attachments (5)
```
sternum and clavical
between the ribs
subscapular fossa
fibula
zygomatic bone
```
152
orientation of muscle fibers (3)
rectus
oblique
orbicularis
153
muscle shape and size (10)
```
deltoid
quadtratus
trapezius
longus
brevis
major
minor
maximus
medius
minimus
```
154
muscle heads/tendons of origin (3)
biceps
triceps
quadriceps
155
adductor
adducts body part
156
abductor
abducts body part
157
flexor
flexes a joint
158
extensor
extends a joint
159
oris
mouth
160
cervicis
neck
161
bracial
arm
162
carpi
wrist
163
pollicis
thumb
164
gluetal
buttocks
165
femoris
thigh
166
hallucis
great toe
167
anterior
toward the front of the bod
168
posterior or dorsal/dorsi
toward the back of the body
169
superficialis
superficial
170
profundus
deep
171
sternum and clavicle
cleido
172
rectus
straight
173
oblique
angled
174
orbicularis
circular
175
deltoid
traingular
176
quadratus
rectangular
177
trapezius
trapezoidal
178
longus
long
179
brevis
short
180
major
larger of two muscle
181
minor
smaller of two muscles
182
maximus
largest
183
medius
medium sized
184
minimus
smallest
185
biceps
two heads
186
triceps
three heads
187
quadriceps
four heads
188
cardiac muscle cells are found within the ____ ____
heart wall
189
qualities of cardiac muscles (6)
```
striated
one or two nuclei
form y-shaped branches
intercalated discs
autorhythmic
involuntary
```
190
intercalated discs
junctions to which other adjacent cardiac muscle fibers can join and comprise of gap junctions
191
autorhythmic
able to generate muscle impulse without nervous stimulation
192
cardiac muscle cells have their nuclei ____ location
centrally
193
smooth muscle is found in the ____ of viscera and ____
walls; blood vessels
194
smooth muscle characteristics (5)
```
short fusiform cells
one centrally located nucleus
no striations
thin filaments attached to dense bodies
under involuntary control
```
195
what feature is not present in skeletal muscle but present in in smooth muscle?
z-disc
196
smooth muscle cells allow contractions in ____ directions
all
