Muscles (KT) Flashcards
1
Q
The scientific study of muscles
A
Myology
2
Q
How much total body mass does muscle account for?
A
45%- responsible for most of the work generated by the body
3
Q
Functions of Muscles (5)
A
- Maintain posture and body position
- Movement
- Heat production
- Guard orifices
- Support visceral organs
4
Q
Properties of Muscle Tissue (4)
A
- Excitability
- Contractility
- Extensibility
- Elasticity
5
Q
The ability to receive and respond to electrical or chemical stimuli
A
Excitability
6
Q
The ability to shorten forcibly when stimulated
A
Contractility
7
Q
The ability to be stretched without damaging the tissue
A
Extendibility
8
Q
The ability to return to original shape after being stretched
A
Elasticity
9
Q
Muscle composition (5)
A
Muscles are organs… The consist of…
- Connective Tissue
- Arteries/Veins
- Nerves
- Lymphatics
- Contractile muscle cells
10
Q
Skeletal Muscle Characteristics (7)
A
- Attaches to bone, skin, or fascia
- Striated with light and dark bands
- Voluntary control
- Long, thin, and multinucleate fibers
- Arranged into packages that attach to and cover the bony skeleton
- Contracts rapidly, but tire easily
- Exert great force
Fiber= 1 muscle cell
11
Q
The main portion of a muscle
A
Belly/Gaster
12
Q
Where is the belly of the muscle attached?
A
Belly is attached to tendons, and then tendons are attached to bones
13
Q
- Dense irregular connective tissue that is around muscle
- Holds it in place and separates it from other muscles
A
Deep Fascia
14
Q
- Loose connective tissue beneath skin
- Surrounds several muscles
A
Subcutaneous Fascia
15
Q
How are skeletal muscles organized? (General)
A
- Many muscle fibers are bundled together into groups called fascicles
- 10-100 muscles fibers per fascicles
- Several fascicles make up a muscle
16
Q
Skeletal muscle connective tissue that surrounds the whole muscle
A
Epimysium
17
Q
Skeletal muscle connective tissue that surrounds the fascicles
A
Perimysium
18
Q
Skeletal muscle connective tissue that separates individual muscle fibers (cells)
A
Endomysium
19
Q
All connective tissue extends beyond the muscle belly to form the….
A
Tendon
20
Q
Tendons that from thick flattened sheets are called…
A
Aponeuroses
21
Q
Embryonic cells that fuse to form muscle fibers… (this is why they are long and multinucleate)
A
Myoblasts
22
Q
Myoblasts that do not fuse become…
A
Myosatellite cells
23
Q
What is the function of Myosatellite cells?
A
Assist in repair of damaged cells
24
Q
Fiber cytoplasm
A
Sarcoplasm
25
Plasma membrane in a fiber
Sarcolemma
26
Extensions of the sarcolemma into the sacroplasm
Transverse (T) Tubule
27
Contractile organelles that...
- Extend the length of fiber
- Surrounded by the sarcoplasmic reticulum
Myofibrils
28
- Surround the myofibrils
- Similar to the ER
- Contain calcium ions
Sarcoplasmic Reticulum
29
What is the functional unit of a myofibril
Sarcomere
30
What are the 2 components of sarcomeres?
1. Thick Filaments
| 2. Thin Filaments
31
What is the component of Thick Filaments?
-Myosin
32
What is the component of myosin?
- Twisted protein with globular heads
- 1.6 um long
- 500 per thick filament
33
What are the components of Thin Filaments? (2)
1. Actin
| 2. Regulatory Proteins
34
Components of Actin... (2)
1. Structural Proteins
| 2. Coiled "beads"
35
Components and function of Regulatory Proteins... (3)
1. Allow/Prohibit attachment between actin and myosin
2. Tropomyosin
3. Troponin
36
Cause the striated appearance
Sarcomere bands
37
What are the 4 kinds of sarcomere bands?
1. A Band
2. I Band
3. H Band
4. Zone of Overlap
38
Type of band that includes the entire thick filament range
A Band
39
Type of band that includes only thin filaments
I Band
40
Type of band that includes only thick filaments
H Band
41
Type of band that includes both filaments
Zone of Overlap
42
These structures divide and flank the sarcomere
Sarcomere Lines
43
What are the 2 types of sarcomere lines?
1. Z line
| 2. M Line
44
This type of sarcomere line...
- Is at the end of the sarcomere
- Made of actinin protein
- Anchors thin filaments
Z Line
45
This type of sarcomere line...
- Is in the middle of the sarcomere
- Stabilizes thick filaments
M Line
46
Structural Protein that...
- Anchors a thick filament to a Z line
- Accounts for elasticity and extensibility
Titin
47
Structural Protein that...
-Holds the F actin together on
thin filaments
Nebulin
48
Structural Protein that...
| -Makes up the Z line
Actinin
49
The process of the actin sliding over the myosin
Sliding Filament Theory
50
What happens during the Sliding filament theory? (5 steps)
1. Zone of overlap enlarges
2. H band shrinks
3. I band shrinks
4. A band remains the same
5. The Z line moves closer to the A band
51
The 6 components of the neuromuscular junction
1. Motor Unit
2. Neuromuscular Junction
3. Synaptic Terminal
4. Motor end plate
5. Synaptic cleft
6. Neurotransmitters
52
Part of the neuromuscular junction that...
| -Neuron + all the muscle cells stimulated by the neuron
Motor Unit
53
Part of the neuromuscular junction that...
| -Point of contact between the neuron and the muscle
Neuromuscular Junction
54
Part of the neuromuscular junction that...
| -End of the axon that contacts motor end plate
Synaptic Terminal
55
Part of the neuromuscular junction that...
| -Point on the muscle fiber that contacts synaptic terminal
Motor End Plate
56
Part of the neuromuscular junction that...
| -Gap between the neuron and the muscle
Synaptic Cleft
57
Part of the neuromuscular junction that...
- Chemical released into the synaptic cleft
- In this case it is acetylcholine
Neurotransmitter
58
Events of Muscle Contraction (9)
1. Ach stored in the synaptic vesicles
2. Impulse reaches end of the neuron--> Ach is released
3. Ach crosses the gap and binds to the receptors
4. Impulse travels through motor end plate down the T- tubules to the sarcoplasmic reticulum
5. Ca+2 ions fiffuse out of the sarcoplasmic reticulum into the sarcoplasm
6. Ca+2 exposes the active site
7. Myosin then binds to active site
8. ATP is used and contraction occurs
9. Contraction continues as long as Ca+2 concentration is high
59
Events of Muscle Relaxation (5)
1. Ach decomposed by acetylcholinesterase (AChe)
2. Ca ions transported back to SR
3. Actin and myosin links broken
4. Cross bridges move back
5. Active site is blocked once again
60
This is determined by the frequency of stimulation and the number of neurons stimulated
Tension
61
Tension in which...
| -All fibers in a motor unit fully contract if stimulated
All or None Law
62
Tension in which...
| -Steady increase in tension by increasing the number of contracting motor neurons
Recruitment
63
Tension in which...
- Muscle never begins to relax
- Continuous fused contraction
Tetanus
64
- Motor untis contract randomly
| - Tension but no movement
Muscle Tone
65
Muscle tone can... (3)
1. Stabilizes joints
2. Holds objects in place
3. Maintains posture
66
- Constant, exhaustive stimulation increases the number of organelles/proteins in a fiber
- Increases the overall enlargement of the muscle
Hypertrophy
67
Hypertrophy increases the number of... (4)
1. Mitochondria
2. Glycolytic enzyme reserves
3. Myofibrils
4. Filaments within myofibrils
68
During hypertrophy, muscle cells (do/do not) reproduce
DO NOT
69
The lack of constant motor neuron stimulation reduces organelles ad proteins
Atrophy
70
Atrophy can be due to... (4)
1. Age
2. Hormones
3. Lack of use
4. Nerve damage
* Is reversible as long as the fiber isn't dead
71
Attachment site that doesn't move
Origin
72
Attachment site that moves
Insertion
73
Tension=
Force
74
Fascicle arrangement varies based on...
Position of the muscle
75
- Fascicles parallel to long axis
| - Unidirectional force
Parallel Muscles
76
Example of parallel muscles
Biceps brachii
77
- Fan shaped muscles
- Multidirectional force
- Versatility
- Generates least amount of force
Convergent Muscles
78
Example of Convergent Muscles
Pectoralis major
79
- Feather shaped muscle
- Fascicles oblique to long axis
- Tendon passes through the muscle
- Greatest force
Pennate Muscle
80
Example of pennate muscle
Deltoid
81
- Concentric fascicles around an opening
| - Contraction decreases lumen diameter
Circular muscles
82
Example of circular muscles
Orbicularis oculi
83
-Rotation around one axis
Uniaxial
84
Uniaxial Movements
Rotation- atlantoaxial and pivot joints
Angular- knee and IP joints
85
Movement along 2 axes
Biaxial
86
Angular movement of biaxial articulations
Angular-
- flexion/extension
- Abduction/Adduction
87
Examples of biaxial Joints (4)
1. Ellipsoidal Joint
2. Radiocarpal
3. Metacarpal Phalange
4. Carpometacarpal (2-5)
88
Movement on all axes
Mutliaxial Movement
89
Multiaxial Movement
Angular-
- Flexion/Extension
- Abduction/Adduction
Rotation-
-Circumduction
90
Example of Multiaxial Movement
Ball and socket
91
- Main muscle causing directional force
| - This can be any muscle of interest
Agonist
92
-Muscle that contracts to oppose agonist
Ex. Bicep brachii
Tricep brachii
Antagonist
93
-Muscle that assists/modifies movement
| Ex. Brachialis and pronator teres
Synergist
94
-Muscle that stabilizes elements associated with agonist
| Ex. Deltoid stabilizes glenohumeral joint
Fixator
95
This type of system modifies movement
Levers
96
Levers can change... (4)
1. Magnitude of force
2. Speed
3. Direction
4. Distance of limb movements
97
The 4 components of the Lever System...
1. Lever (L)
2. Effort (E)
3. Fulcrum (F)
4. Resistance (R)
98
Skeletal Element
Level
99
Applied force
Effort
100
Joint
Fulcrum
101
Body part or object moved
Resistance
102
3 types of levers
1. First Class
2. Second Class
3. Third Class
103
Type of lever that...
| -R opposite of E with central F
First Class
104
E, F, and R of neck extension
E- neck extensions
F- atlanto-occipital joint
R- Skull
105
Type of lever that...
- E is opposite of F to move R
- Example is plantar flexion
Second Class
106
E, F, and R of plantar flexion
E- calf
F- MP joint
R- Weight of body
107
Type of lever that...
- E is in between F and R
- Example is elbow flexion
Third Class
108
E, F, R of elbow flexion
E- biceps brachii
F- elbow joint
R- weight distal to joint
109
Types of Skeletal Muscle Fibers (3)
1. Fast Fibers
2. Slow Fibers
3. Intermediate Fibers
110
Characteristics of Fast Fibers (7)
1. Fast acting, high energy requirements
2. Anaerobic
3. Large diameter
4. Densely packed myofibrils
5. Large glycogen reserves
6. Few mitochondria
7. Rapid, powerful and brief contractions
111
Characteristics of Slow Fibers (5)
1. More myoglobin, slower sustained contraction
2. Aerobic
3. Smaller diameter
4. Longer to contract
5. Contract for longer time
112
Characteristics of Intermediate Fibers
- Has attributes of both
- Similar to fast fibers
- Greater resistance to fatigue
- Exercise or lack of can change one muscle type to another
113
Smooth Muscle characteristics (7)
1. Attached to hair follicles
2. In walls of hollow organs and blood vessels
3. Nonstriated
4. Involuntary control
5. Contractions are slow and sustained
6. Spindle shaped
7. Very elastic
114
Smooth muscles are stimulated by... (4)
1. Nervous System
2. Hormones
3. Ions
4. Stretching
115
Smooth muscle types (2)
1. Single Unit
| 2. Multi Unit
116
-Many gap junctions
-Sheets of spindle shaped cell
-Contract together (syncytial contraction)
Ex. BV's, digestive tract, resp. tract, and urinary tract
Single Unit
117
-Few/No gap junctions
-Separate fibers that contract independently
-Only contract when stimulated by motor nerve
Ex. walls of large BV's, uterus, and iris of eye
Multi Unit
118
Characteristics of Cardiac Muscles
- striated in appearance
- involuntary control
- network of fibers with intercalated disks at the ends
- only found in heart
