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Flashcards in muscular system Deck (198)
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1
Q

Name 2 root words for muscle.

A

myo and sarco

2
Q

the study of muscles

A

myology

3
Q

a skeletal muscle cell

A

myofiber or muscle fiber

4
Q

under conscious control

A

voluntary

5
Q

not under conscious control

A

involuntary

6
Q

striped or banded in appearance

A

striated

7
Q

long, striated, multinucleate, voluntary cylinders

A

skeletal muscle

8
Q

short, branched, striated, uni-nucleate and involuntary muscle

A

cardiac muscle

9
Q

fusiform, uni-nucleate, non-striated, and involuntary

A

smooth muscle

10
Q

4 characteristics of muscle tissue

A
  1. excitability - can react to stimuli
  2. elasticity - snaps back to shape
  3. extensibility - can stretch
  4. contractility - can shorten
11
Q

5 functions of muscle

A
  1. cause movement
  2. produce body heat
  3. protect internal organs
  4. guard entrances and exits to the body
  5. give posture and body position and stabilize joints
12
Q

Why do muscles need a good nerve and blood supply?

A

nerves tell it to contract

blood brings in food and oxygen and carries away waste

13
Q

outer CT covering, over the entire muscle

A

epimysium

14
Q

covering over muscle fascicles

A

perimysium

15
Q

covering over individual muscle fibers

A

endomysium

16
Q

What do the epimysium, perimysium and endomysium form at the ends of a muscle?

A

tendon or aponeurosis

17
Q

What is the difference between a tendon and an aponeurosis?

A

tendon - cord - Achilles (calcaneal)

aponeurosis - sheet - lumbar, galea

18
Q

What travels throughout the perimysium?

A

blood supply and nerves

19
Q

where a muscle starts, usually on the less movable bone

A

origin

20
Q

where a muscle ends, usually on the more movable bone

A

insertion

21
Q

what a muscle does

A

action

22
Q

the nerve supply to a muscle

A

innervation

23
Q

when the epimysium is fused to the periosteum

A

direct attachment

24
Q

Which is more common, an indirect or a direct attachment? Why?

A

indirect - Most muscles have a tendon or aponeurosis because there is less bulk, and it can pass over joints more easily.

25
Q

muscle cell membrane

A

sarcolemma

26
Q

muscle cell cytoplasm

A

sarcolemma

27
Q

muscle ER

A

SR - sarcoplasmic reticulum

28
Q

contractile organelle in a muscle - cylinders of thick and thin myofilaments

A

myofibril

29
Q

contractile unit of a myofibril - from z line to z line

A

sarcomere

30
Q

the stored glycogen granules in a muscle

A

glycosomes

31
Q

pigment in muscle that stores oxygen

A

myoglobin

32
Q

How many myofibrils are in a single muscle fiber?

A

hundreds to thousands - 80% of fiber volume

33
Q

the lighter region of the striations - made of thin fibers

A

I band

34
Q

the darker region of striations - made of the length of the thick fibers

A

A band

35
Q

holds actin threads together and forms a sarcomere

A

z lines

36
Q

holds thick fibers together at middle of sarcomere

A

m line

37
Q

the region where there are both thick and thin fibers

A

zone of overlap

38
Q

the regulatory proteins on the actin

A

troponin and tropomyosin

39
Q

the protein thick fibers are made up of

A

myosin

40
Q

the protein that most of the thin filament is made up of

A

actin

41
Q

the myosin heads form this when they connect to the actin

A

cross bridges

42
Q

the place on the actin where the myosin head attaches

A

active site (binding site)

43
Q

the lighter region in the middle of the A band, where there is no overlap

A

H zone

44
Q

ATPase is what - Where is it found in muscle?

A

enzyme that breaks down ATP - found on the myosin head

45
Q

the elastic protein filament that extends from the thick filament to the Z line and helps it spring back to place

A

titin

46
Q

the end sacs of the SR that hold calcium

A

terminal cisternae (cistern)

47
Q

the protrusions of the sarcolemma into the interior of the muscle fiber

A

t-tubules

48
Q

2 terminal cisternae and 1 t-tubule

A

triad

49
Q

What does the triad correspond to on the sarcomere? Why is this location important?

A

zone of overlap - so calcium is released to the correct location

50
Q

a structural protein that links the thin filaments to the sarcolemma

A

dystrophin

51
Q

the model of muscle contraction

A

sliding filament theory

52
Q

do the actin or myosin molecules shorten when a muscle contracts? Explain.

A

No, they slide past one another as the myosin heads grab and pull on the actin threads. The actin slides toward the M line.

53
Q

a nerve impulse

A

action potential

54
Q

a place where a nerve and muscle meet

A

neuromuscular or myoneural junction

55
Q

neurons that stimulate muscles

A

motor neurons

56
Q

neurons that take information to the CNS

A

sensory neurons

57
Q

the gap between a neuron and a muscle or another neuron

A

synaptic cleft

58
Q

the sacs of chemicals in a synaptic knob

A

synaptic vesicles

59
Q

the chemicals that send nerve messages across the synapse

A

neurotransmitters

60
Q

the neurotransmitter in a neuromuscular junction

A

ACh - acetylcholine

61
Q

what are the folds in the motor end plate, and what is their purpose

A

junctional folds - increase SA - more receptors

62
Q

the cell membrane before the synapse

A

presynaptic membrane

63
Q

the cell membrane after the synapse

A

postsynaptic

64
Q

the sarcolemma of a muscle at the point of the synapse

A

motor end plate

65
Q

the enzyme that breaks down ACh

A

AChE - acetylcholinesterase

66
Q

What is the importance of AChE?

A

allow the message to stop

67
Q

food poisoning that prevents the release of ACh causing paralysis

A

botulism

68
Q

an autoimmune disease that attacks the ACh receptors causing paralysis

A

MG - myasthenia gravis

69
Q

the electrical condition of the motor end plate before it receives the message

A

polarized - having 2 opposite charges on different sides of the membrane

70
Q

What happens to the sarcolemma’s polarity as it sends the message?

A

depolarized - loses its charge difference

71
Q

What has to happen to the sarcolemma’s charge before it can send another message?

A

repolarized - get the opposite charges again

72
Q

How is the membrane repolarized?

A

sodium-potassium pump

73
Q

local depolarization

A

end plate potential

74
Q

the period of time during which the membrane cannot respond to another stimulus because it isn’t completely repolarized

A

refractory period

75
Q

What are the two types of refractory period, and how are they different?

A
  1. absolute refractory period - absolutely no response no matter how strong the stimulus
  2. relative refractory period - will respond if stimulus is strong enough
76
Q

Why does cardiac muscle need a longer refractory period?

A

We want the heart to fill with blood before contracting again.

77
Q

stiffness after death

A

rigor mortis

78
Q

What causes rigor mortis?

A

no ATP or energy so cross bridges don’t release

79
Q

When does rigor mortis finally stop?

A

after myofilaments start to decay

80
Q

When does rigor mortis start? When is its peak time? When does it typically cease?

A

starts - 3 to 4 hours after death
peak - 12 hours after death
stops 48 to 60 hours after death

81
Q

Other than time, what affects rigor mortis?

A

environmental conditions like temperature

82
Q

the force exerted by a contracting muscle

A

muscle tension

83
Q

the opposing force to muscle contraction

A

load

84
Q

when the load is not moved but the tension increases

A

isometric

85
Q

when the load is moved

A

isotonic

86
Q

one motor neuron and all its fibers

A

motor unit

87
Q

How do muscles generate more power?

A

more motor units are recruited

88
Q

Compare motor units in the eye and leg.

A

eye - small and precise

leg - large and powerful

89
Q

a graph of a single contraction/relaxation sequence in a muscle - a muscle twitch

A

myogram

90
Q

the period at the beginning of the myogram where there is not a response yet

A

latent period

91
Q

the upward tracing as tension increases

A

contraction phase

92
Q

the downward tracing as tension decreases

A

relaxation

93
Q

as the stimuli come a little faster and the next twitch is higher

A

wave summation

94
Q

when the muscle reaches maximum tension with some relaxation

A

incomplete tetanus

95
Q

when the stimuli come so fast that no relaxation is seen in the graph

A

complete tetanus

96
Q

All actual muscle activity is what kind of myogram?

A

complete tetanus

97
Q

when our muscles can respond to different needs like lifting something light or something heavy

A

graded muscle response

98
Q

How can we get a graded muscle response? 2 ways

A
  1. stronger stimulus

2. higher frequency stimulus

99
Q

the minimum stimulus necessary to cause a response - 2 terms

A
  1. threshold

2. liminal

100
Q

a stimulus below that necessary to cause a response - 2 terms

A
  1. subthreshold

2. subliminal

101
Q

getting more motor units involved - 2 terms

A
  1. recruitment

2. multiple motor unit summation

102
Q

the strongest stimulus that can increase contractile force

A

maximal stimulus

103
Q

How does recruitment progress?

A

smallest motor units first - largest and least reactive last

104
Q

usually not all motor units are working at the same time so others can rest and take over when needed

A

asynchronous

105
Q

when some muscle fibers are contracted at any given time

A

muscle tone

106
Q

What are the 2 biggest advantages of having muscle tone?

A
  1. higher metabolism - burn food more

2. more stability for joints - muscles are ready to contract if needed

107
Q

What are the two parts of an isotonic contraction, and how are they different?

A
  1. concentric - shortening

2. eccentric - lengthening - stronger

108
Q

usable cellular energy

A

ATP - adenosine triphosphate

109
Q

Where is the energy stored in ATP, and how does the cell get the energy?

A

phosphate bonds - break bonds

110
Q

a chemical that can store phosphate to phosphorylate ADP and make ATP

A

CP - creatine phosphate

111
Q

How long can stored energy in muscles last?

A

14-16 seconds

112
Q

What does the body have to do after the muscles use all their stored energy?

A

make more by respiration

113
Q

What are the 2 kinds of respiration, and how do they compare?

A
  1. aerobic - more efficient (with oxygen) - makes more energy and less waste
  2. anaerobic - less efficient (without oxygen) - makes less energy and more waste
114
Q

What are the end products of aerobic respiration, and what happens to them?

A

CO2 and H2O - exhale them

115
Q

What are the end products of anaerobic respiration, and what happens to them?

A

lactic acid - circulates in blood until it can be removed - makes muscles tired and sore

116
Q

another name for anaerobic respiration

A

glycolysis

117
Q

What does glycolysis literally mean, and how much energy is produced?

A

breakdown of glucose into 2 pyruvic acids - 4 ATP - 2 are invested so a net of 2ATP per glucose

118
Q

What are the advantages of anaerobic respiration?

A

starts quickly and can progress faster - also when there is no oxygen present

119
Q

How long can anaerobic exercises last?

A

a minute

120
Q

What organelle does aerobic respiration? How much ATP is generated?

A

mitochondrion - 32 ATP per glucose

121
Q

the length of time a muscle can use aerobic respiration

A

aerobic endurance - anaerobic threshold

122
Q

the main muscle that causes a movement - 2 terms

A
  1. agonist

2. prime mover

123
Q

the muscle that works opposite the agonist

A

antagonist

124
Q

a muscle that helps with a motion but is not the main muscle

A

synergist

125
Q

a muscle that stabilizes a joint to allow another to work

A

fixator

126
Q

Give 2 examples of antagonistic muscle pairs

A
  1. biceps and triceps

2. quadriceps and hamstrings

127
Q

Give 7 ways muscles are named.

A
  1. location
  2. shape
  3. relative size
  4. direction of fibers
  5. number of origins
  6. location of attachment
  7. action
128
Q

the inability to contract with sufficient neural stimulation

A

fatigue

129
Q

What has to happen for a muscle to recover from activity?

A
  1. release heat
  2. pay back oxygen debt by breathing heavily
  3. replace energy reserves - ATP, glycogen, CP
    `
130
Q

when a muscle loses mass due to inactivity

A

atrophy

131
Q

when a muscle gains mass due to use

A

hypertrophy

132
Q

force generated by cross bridges

A

internal tension

133
Q

force transferred from cross bridges to load

A

external tension

134
Q

how much overlap determines the strength of a contraction - ideal is 80-100% of resting length
- can’t contract with too much or too little overlap

A

length-tension relationship

135
Q

immature muscle cells

A

myoblasts

136
Q

what happens to myoblasts

A

fuse to make a myotube

137
Q

what do we call myoblasts that don’t fuse, and for what are they used

A

satellite cells - repair of damaged muscle

138
Q

What happens to satellite over time - so how is muscle repaired?

A

are used up - get fibrosis instead of regeneration

139
Q

In what direction does muscle develop?

A

head to toe

proximal to distal

140
Q

Who has more muscle mass, men or women and why?

A

men - due to testosterone which stimulates muscle development

141
Q

synthetic male sex hormones

A

anabolic steroids

142
Q

world’s most common genetic disorder, affects muscle - muscle first enlarges due to fat and then atrophies

A

muscular dystrophy

143
Q

the most common form of MD - what causes it

A

Duchenne muscular dystrophy - lack of the protein dystrophin

144
Q

What is the most common cause of death in muscular dystrophy?

A

respiratory failure

145
Q

gradual loss of muscle mass with age

A

sarcopenia

146
Q

a condition that limits blood flow to the muscles of the appendages (particularly the legs) causing pain during walking

A

intermittent claudidication

147
Q

What should be done first for minor muscle injuries?

A

RICE - rest, ice, compression, elevation

148
Q

a sudden, involuntary muscle twitch

A

spasm

149
Q

a pulled muscle with excessive stretching and some torn fibers due to overuse

A

strain

150
Q

inflammation of muscle

A

myositis

151
Q

muscle pain

A

myalgia

152
Q

disease of muscle

A

myopathy

153
Q

How are muscle fibers classified? 2 ways

A
  1. speed of contraction - size of fiber (fast and slow twitch)
  2. how they make energy (glycolytic and oxidative)
154
Q

How do glycolytic fibers get energy?

A

glycolysis - anaerobic

155
Q

How do oxidative fibers get their energy?

A

aerobic respiration - with oxygen

156
Q

fast twitch fiber scientific name

A

slow oxidative

157
Q

slow twitch fiber scientific name

A

fast glycolytic

158
Q

intermediate fiber scientific name

A

fast oxidative

159
Q

What are fast twitch fibers best at?

A

endurance

160
Q

What are slow twitch fibers best at?

A

power - sprints and jumps

161
Q

What is the advantage of intermediate fibers?

A

can be trained to get better at both power and endurance

162
Q

which fibers are thin because they don’t have a lot of stored energy or many myofibrils but with many mitochondria and good blood supply

A

slow oxidative - slow twitch

163
Q

which fibers are thick with lots of stored energy and myofibrils but without a good blood supply and without many mitochondria

A

fast glycolytic - fast twitch

164
Q

Which fiber type would be called red meat? Why

A

slow - good blood supply

165
Q

Which fiber type would be called white meat? Why?

A

fast - poor blood supply

166
Q

Where do the characteristics of the fast oxidative fibers fit in with the other two?

A

intermediate - pink, medium amounts of most everything

167
Q

What determines the predominate fiber type?

A

genetics - interspersed throughout the muscle

- but within a motor unit, they are all the same

168
Q

How does load affect contraction speed?

A

greater load slows contraction speed

169
Q

a disease of chronic inflammation of muscles, its CT and tendons

A

fibromyalgia or fibromyositis

170
Q

protrusion of an organ through a body cavity wall

A

hernia

171
Q

a non-sex linked type of MD, less common than Duchenne MD

A

myotonic dystrophy

172
Q

a disease of sustained, powerful muscular contractions caused by a toxin released from bacteria

A

tetanus

173
Q

Why are people more likely to get tetanus from a puncture wound?

A

doesn’t bleed and flush out the wound

174
Q

What is another name for the disease tetanus and why?

A

lockjaw - jaw muscles are often affected first

175
Q

What does aerobic exercise do to promote endurance?

A

more capillaries, more mitochondria, more myoglobin

176
Q

What kind of muscle activity promotes hypertrophy?

A

resistance exercises like weightlifting

177
Q

What happens to a muscle to make a muscle hypertrophy?

A

larger fibers rather than more fibers - more CT, splitting of fibers

178
Q

What are 5 differences between skeletal and smooth muscle?

A
  1. less CT
  2. different neuromuscular junction - has varicosities and diffuse junctions or swellings instead of the classic bulb…
  3. less developed sarcoplasmic reticulum
  4. no striations - no sarcomeres
  5. have a third kind of myofilament called an intermediate filament which attaches to the sarcolemma at regular intervals by something called a dense body
179
Q

What are the two layers of smooth muscle?

A
  1. longitudinal layer - makes lumen shorter

2. circular layer - constricts lumen

180
Q

the wavelike contractions of smooth muscle that move food through the digestive tract - alternating longitudinal and circular contraction

A

peristalsis

181
Q

What is different about the thick filaments of smooth muscle?

A

fewer and with heads along the entire length

182
Q

What is different about the regulation and calcium binding site of smooth muscle?

A

has a chemical called calmodulin instead of troponin

183
Q

What is the major difference in the arrangement of thick and thin fibers in smooth muscle?

A

diagonal so they twist when they contract

184
Q

Why are smooth muscle fibers synchronized?

A

gap junctions allow transmission from fiber to fiber

185
Q

What is the purpose of pacemaker cells?

A

self-excitatory cells that set the rhythm but can be affected by neural stimulation or hormones

186
Q

a circular muscle that opens or closes a hole

A

sphincter

187
Q

examples of sphincters

A

orbicularis oris and orbicularis oculi

188
Q

muscles with a broad origin and a tendon insertion

A

convergent

189
Q

example of convergent muscles

A

pectoralis major

190
Q

muscles whose fibers run side by side - what is the advantage?

A

parallel - most movement

191
Q

example of parallel muscles

A

sartorius

192
Q

muscles whose fibers come in on an oblique angle to the tendon - like a feather

A

pennate

193
Q

pennate on 1 side, 2 sides, many sides - what is the advantage?

A

unipennate, bipennate, multipennate - most power - especially multipennate

194
Q

muscles with a big belly and a torpedo shape

A

fusiform

195
Q

what provides leverage for muscles?

A

bones

196
Q

what is the fulcrum for the muscles?

A

joints

197
Q

What are the 3 types of lever systems? Give an example for each.

A

1st - seasaws and scissors
2nd - wheelbarrow
3rd - tweezers

198
Q

most muscles in the body are what type of lever?

A

3rd class lever