Musclular System Flashcards

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1
Q

Location of Skeletal Muscle

A

Attached to bones

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2
Q

Location of Cardiac Muscle

A

Heart only

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3
Q

Location of Smooth Muscle

A

forms part of the structure of blood vessels, surrounds many hollow organs

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4
Q

Function of Skeletal Muscle

A

movement of the body

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5
Q

Function of Cardiac Muscle

A

pumping of blood

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6
Q

Function of Smooth Muscle

A

constriction of blood vessels, movement of contents in hollow organs

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7
Q

Basic Anatomy of Skeletal Muscle

A

very large, cylindrical, multinucleate cells arranged in parallel bundles

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8
Q

Basic Anatomy of Cardiac Muscle

A

quadrangular cells with occasional branching points, jointed to other cells by intercalated disks

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9
Q

Basic Anatomy of Smooth Muscle

A

Small, spindle-shaped cells with the long axis generally oriented in the same direction

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10
Q

Striated Muscle Tissues

A

Skeletal and Cardiac

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11
Q

Muscle Tissues with Gap Junctions

A

Cardiac and Smooth

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12
Q

Initiation of Action Potential in Skeletal Muscle

A

Neurons only

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13
Q

Initiation of Action Potential in Cardiac Muscle

A

spontaneous(pacemaker cells), or from another cardiac muscle cell

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14
Q

Initiation of Action Potential in Smooth Muscle

A

spontaneous, whenever slow-wave potentials exceed the threshold

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15
Q

Role of Nerve Stimulation in Skeletal Muscle

A

required for initiation of a twitch contraction,
summation and tetanus are possible

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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

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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

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18
Q

Duration of Electrical Activity in Skeletal Muscle

A

short-duration action potentials (1-2 msec)

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19
Q

Duration of Electrical Activity in Cardiac Muscle

A

long-duration action potentials (200 msec)

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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)

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21
Q

Energy Source for ATP Generation in Skeletal Muscle

A

phosphocreatine, stored glycogen, aerobic metabolism

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22
Q

Energy Source for ATP Generation in Cardiac Muscle

A

aerobic metabolism

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23
Q

Energy Source for ATP Generation in Smooth Muscle

A

aerobic metabolism

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24
Q

Energy Efficiency in Skeletal Muscle

A

low

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25
Q

Energy Efficiency in Cardiac Muscle

A

moderate

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26
Q

Energy Efficiency in Smooth Muscle

A

high

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27
Q

Likelihood of Fatigue in Skeletal Muscle

A

low-very high, depends on energy source and work load, in extreme conditions may fatigue in second

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28
Q

Likelihood of Fatigue in Cardiac Muscle

A

low as long as blood supply is adequate

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29
Q

Likelihood of Fatigue in Smooth Muscle

A

very low

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30
Q

Rate of Muscle Shortening in Skeletal Muscle

A

fast compared to other muscle types, type 2 fibers are faster than type 1

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31
Q

Rate of Muscle Shortening in Cardiac Muscle

A

moderate

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32
Q

Rate of Muscle Shortening in Smooth Muscle

A

very slow

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33
Q

Duration of Contraction in Skeletal Muscle

A

as short as 100 msec for a single twitch, tetanus may be prolonged

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34
Q

Duration of Contraction in Cardiac Muscle

A

short, about 300 msec, summation and tetanus not possible

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35
Q

Duration of Contraction in Smooth Muscle

A

very long, may be sustained indefinitely

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36
Q

Stored ATP Quantities in Muscle

A

stored only in small quantities

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37
Q

Phosphocreatine Quantities in Muscle

A

three to five times the amount of stored ATP

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38
Q

Glycogen Quantities in Muscle

A

variable, some muscle types store large quantities of glycogen

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39
Q

Stored ATP Time Course of Use

A

~10 second

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40
Q

Phosphocreatine Time Course of Use

A

~30 seconds

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41
Q

Glycogen Time Course of Use

A

Primarily used during heavy exercise within the first 3-5 minutes

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42
Q

Aerobic Metabolism Time Course of Use

A

always present

increases dramatically within several minutes of onset of exercise, when blood flow and resipiration increase

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43
Q

Stored ATP Fun Fact

A

ATP is the only direct energy source

it must be replenished by other energy sources

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44
Q

Phosphocreatine Fun Fact

A

converted quickly to ATP

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45
Q

Glycogen Fun Fact

A

glucose can be metabolized to ATP without Oxygen

yields two ATP molecules per glucose molecule

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46
Q

Aerobic Metabolism Fun Fact

A

high yield

complete metabolism of one gluocose molecule yeilds 38 ATP molecules

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47
Q

Functions of Muscluar System

A
  1. Motion - reflex, voluntary, homeostatic
  2. Posture
  3. Heat Production - up to 85% bosy heat
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48
Q

Characteristics of Muscle Tissue

A
  1. Excitability
  2. Contractility
  3. Extensibility
  4. Elasticity
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49
Q

Excitablility of Muscle Tissue

A

receives and responds to stimuli

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50
Q

Contractility of Muscle Tissue

A

shortens with stimuli

contraction is active

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51
Q

Extensibility of Muscle Tissue

A

Extension is passive

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52
Q

Elasticity of Muscle Tissue

A

can return to original shape after Extension or Contraction

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53
Q

Muscle Tissue Types

A
  1. Skeletal
  2. Cardiac
  3. Smooth
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54
Q

Skeletal Muscle

A

striated, voluntary (most), True Syncytium,

syncytium - multinucleate cells

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55
Q

Types of Skeletal Muscle

A
  1. Type 1 Fibers
  2. Type 2 A Fibers
  3. Type 2 B Fibers
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56
Q

Type 1 Fibers

A

slow twitch, fatigue resistant,

Uses Oxidative Phosphorylation for Energy

Red Fiber (myoglobin), Posture Muscles

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57
Q

Myoglobin

A

red protein containing heme, carried and stores Oxygen in muscle tissue

Structurally similar to hemoglobin

58
Q

Type 2 A Fibers

A

fast twitch, fatigue resistant

Uses Oxidative Phosphorylation for Energy

Red Fiber (myoglobin), uncommon (extrinsic eye muscles)

59
Q

Type 2 B Fibers

A

fast twitch, fatigue easily

Uses Glycolysis for Energy

White Fiber (anaerobic), Arm and Leg muscles, sprinting

60
Q

White Fiber (anaerobic)

A

skeletal muscle with low amounts of mitochondria and myoglobin,

61
Q

Red Fiber

A

skeletal muscle with high amounts of mitochondria and myoglobin

62
Q

muscle cell growth

A

due to hypertrophy, increase in myofilaments

no increase in cell number

63
Q

Cardiac Muscle

A

striated, involuntary, functional syncytium,

intercalated disks, Branched Fibers

Autorhythmiticity - 70-20/min

64
Q

Smooth Muscle

A

“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

involuntary, sustained, tonic contraction (peristalsis)

65
Q

Deep Fascia

A

dense, organized connective tissue

surrounds muscle

66
Q

Epimysium

A

wraps entire muscle

sheath of fibrous elastic tissue

67
Q

Perimysium

A

seperates muscles into Fasicles

sheath of connective tissue surrounding a bundle of muscle fibers

68
Q

Muscle Fasicle

A

bundle of skeletal muscle fibers

surrounded by Perimysium

69
Q

Endomysium

A

seperates Fasicles into muscle fibers

sheath of areolar connective tissue that surrounds each individual muscle fiber

70
Q

myofibrils

A

contractile elements within muscle cells

71
Q

periosteum

A

part of bone that Tendons connect to

72
Q

tendon

A

tough band of dense fibrous connective tissue that connects muscle to bone

73
Q

sacrolemma

A

plasma membrane of Muscle Fiber

74
Q

Sarcoplasm

A

cytoplasm of Muscle Fiber

75
Q

Mitochondria

A

organelle that uses aerobic respiration to generate ATP

is located in muscle fibers

“powerhouse of the cell”

76
Q

Myoglobin

A

carries and stores oxygen in muscle fibers

77
Q

T-Tubule

A

increases force of contraction by synchronising calcium release from the Sarcoplasmic Reticulum throughout a cell, helps give structure to the Sarcoplasmic Reticulum

Transverse Tubule

spread of action potential

78
Q

L-Tubule

A

helps give structure to the Sarcplasmic Reticulum

Longitudinal Tubule

79
Q

Sarcoplasmic Reticulum

A

regulates calcium flow, stores calcium,

80
Q

Skeletal Muscle “Triad”

A

T-Tubule bordered by 2 Sarcoplasmic Reticulums

81
Q

Thick Filament

A

Myosin

82
Q

Titin

A

rebound qualities, stabilize sarcomere

83
Q

Thin Filament

A
  1. Actin
  2. Tropomyosin
  3. Nebulin
  4. Troponin
84
Q

Actin

A

Myosin head binding site

85
Q

Tropomyosin

A

alpha helix chain

86
Q

Nebulin

A

structural for strength

87
Q

Types of Troponin

A
  1. TnI
  2. TnT
  3. TnC
88
Q

TnI

A

inhibitory for Actin/Myosin binding

89
Q

TnT

A

anchors complex into tropomyosin

90
Q

TnC

A

Calcium bonding

91
Q

Myofibril arrangements

A

Sarcomere units

92
Q

Z line to Z line

A

sarcomere

disatnce of Z lines shortens with contraction

93
Q

A Band

A

Myosin and Actin

will not shorten with contraction

94
Q

I Band

A

Actin and Z line

distance shortens with contraction

95
Q

H Zone

A

Myosin centers

M line is center of H Zone

distance shortens with contraciton

96
Q

Motor End Plate

A

sarcolemma + axon termials

97
Q

Synaptic Cleft

A

gap between adjacent neurons

98
Q

Neurotransmitter of the Neuromuscular Junction

A

Acetyl Choline (ACh)

99
Q

Motor Unit

A

axon + all Muscle Fibers it controls

100
Q

Precise Control

A

few muscle fibers per axon

eye muscles

3-10 muscle fibers

101
Q

gross control

A

many muscle fibers per axon

Biceps Brachii, Gastrocnemious

1000-2000 smaller motor units, more excitable

102
Q

All or None Law

A

If threshold stimulus is applied, all muscle fibers controlled by a particular motor unit will fire

103
Q

Recruitment

A

adjusting number and firing rates of motor units for smooth, sustained, contraction

104
Q

Where is muscle contration initiated?

A

A band, where thick and thin filaments overlap

105
Q

Tropomyosin and muscle contraction

A

when resting myosin and actin binding is blocked by Tropomyosin

106
Q

Steps of Muscle Contraction

A
  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
Q

What shortens during muscle contraction?

A

sarcomere, H Zone, I Band, Z line to Z line distance

108
Q

Rigor Mortis

A

No ATP available, Actin/Myosin complex becomes stable

slow Ca++ influx, but no ATP to break the complex

109
Q

Steps of Muscle Contraction that require ATP

A

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
Q

Creatine Phosphate

A

Phosphate store that donates phosphate to augment ADP + Pi = ATP

30 second supply

111
Q

metabolism of blood glucose

A

longterm ATP generation

also liver glycogenolysis

112
Q

Anaerobic glycolysis

A

yields 2 ATP

lactic acid builds up

113
Q

Aerobic glycolysis

A

total yield of 38 ATP

Krebs cycle, glycolysis

114
Q

Tetrodotoxin

A

blocks Na+, prevents nervous system from carrying messages, prevents muscle contraction

115
Q

Botulinum

A

blocks ACh release, causes flaccid paralysis

botox facelift

116
Q

Curare

A

blocks ACh binding, paralyzing agent, causes weakness of skeletal muscles,

eventual death from asphixiation due to paralysis of the diaphragm

117
Q

Sarin Nerve Gas

A

blocks Acetylcholinesterase, nerve impulses from acetylcholine are continually transmitted

118
Q

Length Tension Curve

A

as a muscle shortens tension increases to a point until thin filaments start to overlap

think bicep curl getting easier towards the top

119
Q

Isometric Contration

A

muscle develops tension but does not shorten

120
Q

Muscle Twitch Stimulus Response

A
  1. Treppe
  2. Summation (staircase)
  3. Tetanus
  4. Fatigue
121
Q

Treppe

A

initial contraction after rest submaximal

repeated contraction become more powerful

more Ca++ available from the Sarcoplasm

122
Q

Summation (staircase)

A

absolute and relative refractory periods of axons are brief compared to muscle twitch time

can re-stimulate a muscle before it has relaxed

force from first stimulus can be added to second

123
Q

Tetanus

A

flat line response (20-60 stim/sec, action potentials released very fast)
Incomplete fusion: stimuli spaced far apart
Complete fusion: stimuli spaced close together

cardiac muscle will not tetanize

124
Q

Fatigue

A

muscle depletes glycogen stores

125
Q

Multiunit trait of Smooth Muscle

A

each cell operates as a discreate unit,

fires seperately

each unit is controlled by nerves

126
Q

Unitary or Visceral

A

linked by gap junctions,

functional syncytium

uterus, bladder, small vessels, GI tract

127
Q

What stimulates Smooth Muscle?

A
  1. Nerves
  2. spontaneous depolarization (slow waves)
  3. hormones
  4. local factors (O2, CO2, temp, prostaglandins)
  5. an increase in plasma Ca++
128
Q

Amount of Myosin in Smooth Muscle

A

very little

129
Q

uses of Calmodium(Ca++ binding) in Smooth Muscle

A
  1. activates mysosin light chain kinase (MLCK)
  2. causes phosphorylation of myosin
  3. causes cycling of myosin heads
130
Q

location of contraction regulation in skeletal muscle

A

Thin filament

actin

131
Q

location of contraction in smooth muscle

A

myosin

132
Q

Muscular Dystrophy

A

genetic based degeneration of skeletal muscle fibers

muscle tears, Ca++ enters

necrosis, macrophages, proximal muscles too

133
Q

Dystrophin

A

structural membrane protein is lacking in muscular dystrophy

134
Q

Myasthenia Gravis

A

abnormality in neuromuscular junction

autoimmune disorder against ACh receptors on muscle

neostigmine treatment AChase inhibitor

135
Q

Multiple Sclerosis

A

degeneration of myelin on nerves that direct muscle contraction

136
Q

Anabolic Steroids

A

increase protein sysnthesis in muscle,

stimulates tumor growth, causes liver problems, causes psychological problems (Roidmania)

137
Q

Charley Horse

A

bruise/tear of a muscle, followed by bleeding (hematoma)

138
Q

Tennis Elbow

A

aggravation of the tendons of the forearm extensors by lateral epicondyle of humerous

139
Q

peristalsis

A

involuntary contracting and relaxing of intestinal walls,

140
Q

Steps of Muscle Contraction in Smooth Muscle

A
  1. Ca++ binds to calmodium
  2. MLCK is activated
  3. increases ATPase activity
  4. increased tension, contraction
141
Q

Compartment Syndrome

A

swelling of lower calf muscles due to over exertion

muscle swells in fascia, no blood flow