Chapter 1 & 11 Flashcards
1
Q
The Anatomy of skeletal muscle consist of what 2 things?
A
Muscle fibers
Myofibrils
2
Q
What are the 3 types of muscle tissue?
A
Skeletal
Smooth
Cardiac
3
Q
Of the 3 types of muscle tissue, which is voluntary?
A
Skeletal
4
Q
What does the skeletal muscle connect to?
A
Skeleton
5
Q
Where is smooth muscle found?
A
Hollow organs
6
Q
Where is cardiac muscle found?
A
Heart
7
Q
An entire muscle is surrounded by __________.
A
Epimysium
8
Q
An entire muscle consists of many _______ (fascicles or fasciculi)
A
Bundles
9
Q
The fascicle is surrounded by _______.
A
Perimysium
10
Q
The fascicle consist of individual _____ cells.
A
Muscle
11
Q
Each muscle fiber is surrounded by _________.
A
Endomysium
12
Q
Muscle fivers consists of myofibrils divided into _________.
A
Sacromeres
13
Q
Plasmalemma (cell membrane) fuses with _____.
A
Tendon
14
Q
What are the 3 jobs of plasmalemma? (CapMpTn)
A
- conducts action potential
- maintains pH
- Transports nutrients
15
Q
What is the cytoplasm of the muscle cell?
A
Sarcoplasm
16
Q
What are 2 unique features of sarcoplasm? (GsM)
A
Glycogen storage & myoglobin
17
Q
_________ are extensions of plasmalemma.
A
Transverse tubules
18
Q
What carries action potential deep into muscle fiber?
A
T-Tubules
19
Q
Where is Calcium stored in muscle fibers?
A
Sarcoplasmic reticulum
20
Q
What is the sequence of myofibril creation?
A
Muscle —> fascicle —> muscle fiber —> myofibril
21
Q
What is the amount of myofibrils per muscle fiber?
A
Hundreds to thousands
22
Q
Sections of myofibrils are known as what?
A
Sarcomeres
23
Q
What is the basic contractile element of skeletal muscle?
A
Sarcomeres
24
Q
To estimate the full length of a myofibril, how should you measure it?
A
End to end
25
What are the distinctive striped appearances located on sarcomeres?
Striations
26
Describe Sarcomere A-bands.
Dark/blue stripes
27
Describe Sarcomere I-bands.
light/pink stripes
28
Describe Sarcomere H-zone.
Middle of A-band
29
Describe Sarcomere M-line.
middle of H-zone
30
T/F: A-band has both thick and thin filament
True
31
T/F: A-bands length is measured using both thick and thin filament.
False; only thick filament
32
T/F: I-band consists of thin filament.
True
33
What is common boundary structure of the sarcomere?
Z-disk or Z-line
34
T/F: H-zone consists of thick filament.
True
35
What are 2 important proteins of the sarcomere?
Actin & Myosin
36
Thin filaments are composed of what 3 proteins?
Actin
Tropomyosin
Troponin
37
_______: contains myosin-binding site.
Actin
38
What protein covers the active site at rest?
Tropomyosin
39
What protein is anchored to actin and moves Tropomyosin?
Troponin
40
Myosin is two intertwined ________ with globular heads.
Filaments
41
T/F: Globular heads can protrude 360 degrees from thick filament axis.
True
42
T/F: Globular heads will not interact with actin filaments for contraction.
False; they will interact
43
T/F: Myosin uses Titin as a stabilizer.
True
44
What myofilament acts like a spring?
Titin
45
T/F: Titin extends from Z-disk to M-band.
True
46
What are the 2 main jobs of Titin?
Stabilizes sarcomeres and centers myosin
Prevents overstretching
47
Muscle fiber contraction starts with ________.
nervous system
48
Which type of motor neurons innervate muscle fibers?
Alpha
49
T/F: More operating motor units = more contractile force
True
50
Fibers contract through a sequence of events known as what?
Excitation-contraction coupling
51
What are the 6 sequences of excitation-contraction coupling? (AAAATC)
1. Action potential (AP) starts in brain
2. AP arrives at axon terminal, releases ACh
3. ACh crosses synapse, binds to ACh receptors on plasmalemma
4. AP travels down plasmalemma, T-Tubules
5. Triggers Ca+2 release from sarcoplasmic reticulum (SR)
6. Ca+2 enables actin-myosin contraction
52
T/F: SR sensitive to electrical charge.
True
53
When AP arrives at SR from T-tubule, is causes mass release of _____ into _____.
Ca+2 ; sarcoplasm
54
_______ binds to ______ on _____ filament.
Ca+2 ; troponin ; thin
55
When Ca+2 binds to troponin on thin filament, myosin binds to actin forming a ________ allowing a contraction to occur.
Cross-bridge
56
The Sliding Filament Theory is a process of _________ contraction.
Actin-myosin
57
What happens during the relaxed state of sliding filament theory?
- No actin-myosin interaction at binding site
- Myofilaments overlap a little
58
What happens during the contracted state of the sliding filament theory?
- Myosin head pulls actin toward sarcomere center
- Filaments slide past each other
- Sarcomeres, myofibrils, muscle fiber all shorten
59
What is power stroke?
Myosin head pulling actin toward sarcomere center.
60
What happens after power stroke ends?
- Myosin detaches from active site
- Myosin head rotates back to original position
- Myosin attaches to another active site farther down
61
The sliding filament theory continues until what 1 of 2 things happen?
- Z-disk reaches myosin filaments OR AP stops, Ca+2 gets pumped back into SR.
62
What is a cross-bridge?
When myosin meets actin
63
What is the energy unit for muscle contraction?
ATP
64
ATP binds to _____ head.
Myosin
65
What is located on the myosin head?
ATPase
66
T/F: ATP is necessary for muscle contraction.
True
67
When muscle relaxation occurs, what 2 things end/stop.
1. AP ends
2. Electrical stimulation of SR stops.
68
What length does not change during muscle contraction?
A-band
69
T/F: Muscle relaxation requires ATP.
True
70
T/F: Muscle biopsy consist of a small (10-100g) piece of muscle removed and is frozen, sliced, examined under microscope.
True
71
What are the colors designated with a certain type of muscle fiber:
Type 1
Type 2a
Type 2x
Type 1: black
Type 2a: white
Type 2x: gray
72
Type _______ muscle fiber has a slow form of myosin ATPase
1
73
Type _____ muscle fiber has a fast form of myosin ATPase.
2
74
What is the percentages of each muscle fiber type?
Type 1: 50%
Type 2a: 25%
Type 2x: 25%
75
Which type of muscle fiber has high aerobic endurance?
Type 1
76
Which muscle fiber type is being described:
- Efficiently produce ATP from oxidation of fat and carbohydrate
- Can maintain exercise for prolonged periods
- Require oxygen for ATP production
- Recruited most often during low intensity
- aerobic exercise (e.g., marathon running)
- daily activities (walking)
- posture
Type 1
77
Type II fibers in general are ____ in aerobic endurance and produce ATP through ______ pathways.
Poor ; anaerobic
78
Type _____ produce more force, faster fatigue than type ____ and are primarily used in short, high intensity endurance events (1,600m run).
IIa ; I
79
Type ______ are seldomly used for everyday activities and primarily used in short,explosive sprints (100m).
IIx
80
Which muscle fiber type’s motor unit has a greater neuron size?
Type II
81
List the muscle fiber types in order of greatest peak power to least peak power.
Type IIx > Type IIa > Type I
82
T/F: Each person has unique ratios of muscle fiber types.
True
83
Type I predominates in ______ athletes and Type II predominates in _____ athletes.
Endurance ; power
84
T/F: The Soleus is type I in everyone.
True
85
T/F: The lose of type II motor units occurs with aging.
True
86
T/F: Fiber type is the sole predictor of success.
False
87
What are the 4 factors of athletic success? (CfMThMs)
- Cardiovascular function
- Motivation
- Training habits
- Muscle size
88
When a motor unit is recruited, ___ of its fibers are ______.
ALL ; activated
89
Less force: _____ or ______ motor units (type __)
Fewer ; smaller ; I
90
More force: ____ or _____ motor units (type __)
More ; larger ; II
91
What is the recruitment order?
1. Smallest (type I) motor units
2. Midsized (type IIa) motor units
3. Largest (type IIx) motor units
92
What is the principle that states: “order of recruitment of motor units directly related to size of alpha-motor neuron”.
Principle of orderly recruitment (size principle)
93
Smaller motor units are ___-threshold.
Low
94
Progressively higher threshold motor units are recruited based on the increasing demands of the _______.
Activity
95
Which muscle contraction type requires muscle to produce force and change length ; joint movement produced?
Dynamic
96
What are the two subtypes of dynamic muscle contraction?
Concentric & Eccentric
97
T/F: Concentric contraction implies that the muscle shortens while producing force.
True
98
Which contraction requires the muscle to lengthen?
Eccentric
99
Which muscle contraction is being described:
- Muscle produces force but does not change length
- Joint angle does not change
- Myosin cross-bridges form and recycle, no sliding
Static (isometric)
100
Amount of force developed depends on what 5 things?
1. Number and type of motor units activated
2. Size of the muscle
3. Frequency of stimulation of each motor unit
4. Muscle fiber and sarcomere length
5. Speed of contraction
101
T/F: More force generated when more motor units activated.
True
102
What is the contractile response to single electrical stimulus?
Twitch
103
What are consecutive stimuli for greater force?
Summation
104
What is continued stimulation resulting in peak force?
Tetanus
105
What it’s the process of varying levels within the frequency of stimulation?
Rate coding
106
T/F: Optimal sarcomere length = optimal overlap of actin/myosin
True
107
T/F: Too short or too stretched = little or great force develops .
False; little to no force
108
The ability to develop force also depends on speed of contraction is known as what relationship?
Speed-Force
109
Concentric: maximal force development _______ at _____ speeds.
Decreases ; higher
110
Eccentric: maximal force development ______ at _____ speeds.
Increases ; higher
111
Substantial strength gains via ___________ changes.
Neuromuscular
112
T/F: Resistance Training is important for overall fitness and health.
True
113
After ____ to ____ months of resistance training, you can notice 25 to 100% strength gain, learn more effectively to produce force, learn to produce true maximal movement.
3 to 6
114
Why do young men experience greatest absolute gains versus young women, older men, and children?
Incredible muscle plasticity
