Musclular System Flashcards
1
Q
Location of Skeletal Muscle
A
Attached to bones
2
Q
Location of Cardiac Muscle
A
Heart only
3
Q
Location of Smooth Muscle
A
forms part of the structure of blood vessels, surrounds many hollow organs
4
Q
Function of Skeletal Muscle
A
movement of the body
5
Q
Function of Cardiac Muscle
A
pumping of blood
6
Q
Function of Smooth Muscle
A
constriction of blood vessels, movement of contents in hollow organs
7
Q
Basic Anatomy of Skeletal Muscle
A
very large, cylindrical, multinucleate cells arranged in parallel bundles
8
Q
Basic Anatomy of Cardiac Muscle
A
quadrangular cells with occasional branching points, jointed to other cells by intercalated disks
9
Q
Basic Anatomy of Smooth Muscle
A
Small, spindle-shaped cells with the long axis generally oriented in the same direction
10
Q
Striated Muscle Tissues
A
Skeletal and Cardiac
11
Q
Muscle Tissues with Gap Junctions
A
Cardiac and Smooth
12
Q
Initiation of Action Potential in Skeletal Muscle
A
Neurons only
13
Q
Initiation of Action Potential in Cardiac Muscle
A
spontaneous(pacemaker cells), or from another cardiac muscle cell
14
Q
Initiation of Action Potential in Smooth Muscle
A
spontaneous, whenever slow-wave potentials exceed the threshold
15
Q
Role of Nerve Stimulation in Skeletal Muscle
A
required for initiation of a twitch contraction,
summation and tetanus are possible
16
Q
Role of Nerve Stimulation in Cardiac Muscle
A
stimulatory and inhibitory nerves modulate the heart rate and force of contraction, not required for cardiac muscle to function
17
Q
Role of Nerve Stimulation in Smooth Muscle
A
stimulatory and inhibitory nerves can modulate a degree of tension developed, not required for smooth muscle to function
18
Q
Duration of Electrical Activity in Skeletal Muscle
A
short-duration action potentials (1-2 msec)
19
Q
Duration of Electrical Activity in Cardiac Muscle
A
long-duration action potentials (200 msec)
20
Q
Duration of Electrical Activity in Smooth Muscle
A
very long slow waves at roughly 10 second intervals,
occasional superimposed long-duration action potentials (300 msec)
21
Q
Energy Source for ATP Generation in Skeletal Muscle
A
phosphocreatine, stored glycogen, aerobic metabolism
22
Q
Energy Source for ATP Generation in Cardiac Muscle
A
aerobic metabolism
23
Q
Energy Source for ATP Generation in Smooth Muscle
A
aerobic metabolism
24
Q
Energy Efficiency in Skeletal Muscle
A
low
25
Energy Efficiency in Cardiac Muscle
moderate
26
Energy Efficiency in Smooth Muscle
high
27
Likelihood of Fatigue in Skeletal Muscle
low-very high, depends on energy source and work load, in extreme conditions may fatigue in second
28
Likelihood of Fatigue in Cardiac Muscle
low as long as blood supply is adequate
29
Likelihood of Fatigue in Smooth Muscle
very low
30
Rate of Muscle Shortening in Skeletal Muscle
fast compared to other muscle types, type 2 fibers are faster than type 1
31
Rate of Muscle Shortening in Cardiac Muscle
moderate
32
Rate of Muscle Shortening in Smooth Muscle
very slow
33
Duration of Contraction in Skeletal Muscle
as short as 100 msec for a single twitch, tetanus may be prolonged
34
Duration of Contraction in Cardiac Muscle
short, about 300 msec, summation and tetanus not possible
35
Duration of Contraction in Smooth Muscle
very long, may be sustained indefinitely
36
Stored ATP Quantities in Muscle
stored only in small quantities
37
Phosphocreatine Quantities in Muscle
three to five times the amount of stored ATP
38
Glycogen Quantities in Muscle
variable, some muscle types store large quantities of glycogen
39
Stored ATP Time Course of Use
~10 second
40
Phosphocreatine Time Course of Use
~30 seconds
41
Glycogen Time Course of Use
Primarily used during heavy exercise within the first 3-5 minutes
42
Aerobic Metabolism Time Course of Use
always present
## Footnote
increases dramatically within several minutes of onset of exercise, when blood flow and resipiration increase
43
Stored ATP Fun Fact
ATP is the only direct energy source
## Footnote
it must be replenished by other energy sources
44
Phosphocreatine Fun Fact
converted quickly to ATP
45
Glycogen Fun Fact
glucose can be metabolized to ATP without Oxygen
## Footnote
yields two ATP molecules per glucose molecule
46
Aerobic Metabolism Fun Fact
high yield
## Footnote
complete metabolism of one gluocose molecule yeilds 38 ATP molecules
47
Functions of Muscluar System
1. Motion - reflex, voluntary, homeostatic
2. Posture
3. Heat Production - up to 85% bosy heat
48
Characteristics of Muscle Tissue
1. Excitability
2. Contractility
3. Extensibility
4. Elasticity
49
Excitablility of Muscle Tissue
receives and responds to stimuli
50
Contractility of Muscle Tissue
shortens with stimuli
## Footnote
contraction is active
51
Extensibility of Muscle Tissue
Extension is passive
52
Elasticity of Muscle Tissue
can return to original shape after Extension or Contraction
53
Muscle Tissue Types
1. Skeletal
2. Cardiac
3. Smooth
54
Skeletal Muscle
striated, voluntary (most), True Syncytium,
## Footnote
syncytium - multinucleate cells
55
Types of Skeletal Muscle
1. Type 1 Fibers
2. Type 2 A Fibers
3. Type 2 B Fibers
56
Type 1 Fibers
slow twitch, fatigue resistant,
| Uses Oxidative Phosphorylation for Energy
## Footnote
Red Fiber (myoglobin), Posture Muscles
57
Myoglobin
red protein containing heme, carried and stores Oxygen in muscle tissue
## Footnote
Structurally similar to hemoglobin
58
Type 2 A Fibers
fast twitch, fatigue resistant
| Uses Oxidative Phosphorylation for Energy
## Footnote
Red Fiber (myoglobin), uncommon (extrinsic eye muscles)
59
Type 2 B Fibers
fast twitch, fatigue easily
| Uses Glycolysis for Energy
## Footnote
White Fiber (anaerobic), Arm and Leg muscles, sprinting
60
White Fiber (anaerobic)
skeletal muscle with low amounts of mitochondria and myoglobin,
61
Red Fiber
skeletal muscle with high amounts of mitochondria and myoglobin
62
muscle cell growth
due to hypertrophy, increase in myofilaments
## Footnote
no increase in cell number
63
Cardiac Muscle
striated, involuntary, functional syncytium,
| intercalated disks, Branched Fibers
## Footnote
Autorhythmiticity - 70-20/min
64
Smooth Muscle
"muscle of organs" blood vessels, respiratory passages, Gi system, Urinary system, Arrector Pilli of skin, Iris of eye
| not striated, thick and thin filaments, no Z lines
## Footnote
involuntary, sustained, tonic contraction (peristalsis)
65
Deep Fascia
dense, organized connective tissue
| surrounds muscle
66
Epimysium
wraps entire muscle
## Footnote
sheath of fibrous elastic tissue
67
Perimysium
seperates muscles into Fasicles
## Footnote
sheath of connective tissue surrounding a bundle of muscle fibers
68
Muscle Fasicle
bundle of skeletal muscle fibers
## Footnote
surrounded by Perimysium
69
Endomysium
seperates Fasicles into muscle fibers
## Footnote
sheath of areolar connective tissue that surrounds each individual muscle fiber
70
myofibrils
contractile elements within muscle cells
71
periosteum
part of bone that Tendons connect to
72
tendon
tough band of dense fibrous connective tissue that connects muscle to bone
73
sacrolemma
plasma membrane of Muscle Fiber
74
Sarcoplasm
cytoplasm of Muscle Fiber
75
Mitochondria
organelle that uses aerobic respiration to generate ATP
| is located in muscle fibers
## Footnote
"powerhouse of the cell"
76
Myoglobin
carries and stores oxygen in muscle fibers
77
T-Tubule
increases force of contraction by synchronising calcium release from the Sarcoplasmic Reticulum throughout a cell, helps give structure to the Sarcoplasmic Reticulum
| Transverse Tubule
## Footnote
spread of action potential
78
L-Tubule
helps give structure to the Sarcplasmic Reticulum
| Longitudinal Tubule
79
Sarcoplasmic Reticulum
regulates calcium flow, stores calcium,
80
Skeletal Muscle "Triad"
T-Tubule bordered by 2 Sarcoplasmic Reticulums
81
Thick Filament
Myosin
82
Titin
rebound qualities, stabilize sarcomere
83
Thin Filament
1. Actin
2. Tropomyosin
3. Nebulin
4. Troponin
84
Actin
Myosin head binding site
85
Tropomyosin
alpha helix chain
86
Nebulin
structural for strength
87
Types of Troponin
1. TnI
2. TnT
3. TnC
88
TnI
inhibitory for Actin/Myosin binding
89
TnT
anchors complex into tropomyosin
90
TnC
Calcium bonding
91
Myofibril arrangements
Sarcomere units
92
Z line to Z line
sarcomere
## Footnote
disatnce of Z lines shortens with contraction
93
A Band
Myosin and Actin
## Footnote
will not shorten with contraction
94
I Band
Actin and Z line
## Footnote
distance shortens with contraction
95
H Zone
Myosin centers
| M line is center of H Zone
## Footnote
distance shortens with contraciton
96
Motor End Plate
sarcolemma + axon termials
97
Synaptic Cleft
gap between adjacent neurons
98
Neurotransmitter of the Neuromuscular Junction
Acetyl Choline (ACh)
99
Motor Unit
axon + all Muscle Fibers it controls
100
Precise Control
few muscle fibers per axon
| eye muscles
## Footnote
3-10 muscle fibers
101
gross control
many muscle fibers per axon
| Biceps Brachii, Gastrocnemious
## Footnote
1000-2000 smaller motor units, more excitable
102
All or None Law
If threshold stimulus is applied, all muscle fibers controlled by a particular motor unit will fire
103
Recruitment
adjusting number and firing rates of motor units for smooth, sustained, contraction
104
Where is muscle contration initiated?
A band, where thick and thin filaments overlap
105
Tropomyosin and muscle contraction
when resting myosin and actin binding is blocked by Tropomyosin
106
Steps of Muscle Contraction
1. Axon Terminal depolarizes (Ca++ influx, ACh release across the synapse)
2. ACh binds the Sarcolemma Receptors
3. Chemically gated Na+ gates open, Na+ influx into muscle, depolarization
4. T-Tubule system spreads action potential along sarcomere (depolarization wave)
5. Electrical potential causes Sarcoplasmic Reticulum to release Ca++
6. Ca++ bind to Troponin, causes movement of Tropomyosin, Exposure of Myosin-Actin binding site
7. Binding between Myosin and Actin binding site
8. Ratcheting of Mysoin head due to ADP leaving, causing conformation change
9. new ATP binds to Myosin, causes dissociation of actin/myosin, resets myosin head
10. Repeats 7, 8, and 9 providing Ca++ is present
11. When stimulation ceases, Ca++ is sequestered in Sarcoplasmic Reticulum, binding sites blocked, muscle relaxes
107
What shortens during muscle contraction?
sarcomere, H Zone, I Band, Z line to Z line distance
108
Rigor Mortis
No ATP available, Actin/Myosin complex becomes stable
## Footnote
slow Ca++ influx, but no ATP to break the complex
109
Steps of Muscle Contraction that require ATP
8 Ratcheting of Mysoin head due to ADP leaving, causing conformation change
9 new ATP binds to Myosin, causes dissociation of actin/myosin, resets myosin head
11 When stimulation ceases, Ca++ is sequestered in Sarcoplasmic Reticulum, binding sites blocked, muscle relaxes
110
Creatine Phosphate
Phosphate store that donates phosphate to augment ADP + Pi = ATP
## Footnote
30 second supply
111
metabolism of blood glucose
longterm ATP generation
## Footnote
also liver glycogenolysis
112
Anaerobic glycolysis
yields 2 ATP
| lactic acid builds up
113
Aerobic glycolysis
total yield of 38 ATP
| Krebs cycle, glycolysis
114
Tetrodotoxin
blocks Na+, prevents nervous system from carrying messages, prevents muscle contraction
115
Botulinum
blocks ACh release, causes flaccid paralysis
## Footnote
botox facelift
116
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Curare
blocks ACh binding, paralyzing agent, causes weakness of skeletal muscles,
## Footnote
eventual death from asphixiation due to paralysis of the diaphragm
117
Sarin Nerve Gas
blocks Acetylcholinesterase, nerve impulses from acetylcholine are continually transmitted
118
Length Tension Curve
as a muscle shortens tension increases to a point until thin filaments start to overlap
| think bicep curl getting easier towards the top
119
Isometric Contration
muscle develops tension but does not shorten
120
Muscle Twitch Stimulus Response
1. Treppe
2. Summation (staircase)
3. Tetanus
4. Fatigue
121
Treppe
initial contraction after rest submaximal
| repeated contraction become more powerful
## Footnote
more Ca++ available from the Sarcoplasm
122
Summation (staircase)
absolute and relative refractory periods of axons are brief compared to muscle twitch time
| can re-stimulate a muscle before it has relaxed
## Footnote
force from first stimulus can be added to second
123
Tetanus
flat line response (20-60 stim/sec, action potentials released very fast)
Incomplete fusion: stimuli spaced far apart
Complete fusion: stimuli spaced close together
## Footnote
cardiac muscle will not tetanize
124
Fatigue
muscle depletes glycogen stores
125
Multiunit trait of Smooth Muscle
each cell operates as a discreate unit,
| fires seperately
## Footnote
each unit is controlled by nerves
126
Unitary or Visceral
linked by gap junctions,
| functional syncytium
## Footnote
uterus, bladder, small vessels, GI tract
127
What stimulates Smooth Muscle?
1. Nerves
2. spontaneous depolarization (slow waves)
3. hormones
4. local factors (O2, CO2, temp, prostaglandins)
5. an increase in plasma Ca++
128
Amount of Myosin in Smooth Muscle
very little
129
uses of Calmodium(Ca++ binding) in Smooth Muscle
1. activates mysosin light chain kinase (MLCK)
2. causes phosphorylation of myosin
3. causes cycling of myosin heads
130
location of contraction regulation in skeletal muscle
Thin filament
## Footnote
actin
131
location of contraction in smooth muscle
myosin
132
Muscular Dystrophy
genetic based degeneration of skeletal muscle fibers
| muscle tears, Ca++ enters
## Footnote
necrosis, macrophages, proximal muscles too
133
Dystrophin
structural membrane protein is lacking in muscular dystrophy
134
Myasthenia Gravis
abnormality in neuromuscular junction
| autoimmune disorder against ACh receptors on muscle
## Footnote
neostigmine treatment AChase inhibitor
135
Multiple Sclerosis
degeneration of myelin on nerves that direct muscle contraction
136
Anabolic Steroids
increase protein sysnthesis in muscle,
## Footnote
stimulates tumor growth, causes liver problems, causes psychological problems (Roidmania)
137
Charley Horse
bruise/tear of a muscle, followed by bleeding (hematoma)
138
Tennis Elbow
aggravation of the tendons of the forearm extensors by lateral epicondyle of humerous
139
peristalsis
involuntary contracting and relaxing of intestinal walls,
140
Steps of Muscle Contraction in Smooth Muscle
1. Ca++ binds to calmodium
2. MLCK is activated
3. increases ATPase activity
4. increased tension, contraction
141
Compartment Syndrome
swelling of lower calf muscles due to over exertion
## Footnote
muscle swells in fascia, no blood flow
