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A&P 1 > Chapter 10 > Flashcards

Chapter 10 Flashcards

1
Q

Why are skeletal muscles on either sides of joints?

A

to stabilize them

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2
Q

What is contractility?

A

shorten using energy; return to shape when relaxed

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3
Q

What is excitability?

A

electrical events can be started in skeletal muscles (called an action potential)

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4
Q

What does it mean that a skeletal muscle is conductive?

A

muscles are long, so the whole muscle can get “excited”

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5
Q

What is distensibility?

A

stretch

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6
Q

What is elasticity?

A

recoil

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7
Q

How do muscle fibers develop?

A

through fusion of myoblasts

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8
Q

How do myoblasts form muscle fibers?

A

myosatellite cells give rise to new myoblasts that fuse together to form muscle fiber

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9
Q

Where do nuclei sit in skeletal muscle fibers?

A

on the edges (peripheral); right up under plasma membrane

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10
Q

What causes striations in mature muscle cells?

A

proteins

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11
Q

What is one of the roles of muscle fiber nuclei?

A

constantly fixing proteins in cells and making proteins

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12
Q

What is the sarcolemma?

A

plasma membrane of the muscle fiber
surrounds sarcoplasm

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13
Q

What is the sarcolemma capable of?

A

changing charge
a change in transmembrane potential at the sarcolemma begins contractions

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14
Q

What are transverse (T) tubules?

A

tunnels that have inside open to ECF
filled with positive fluid, compared to negative charge inside cell

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15
Q

How does an action potential travel in the muscle cell?

A

travels down sarcolemma and down t-tubules, setting off charge change

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16
Q

What is the sarcoplasmic reticulum?

A

a membranous structure surrounding each myofibril
stores calcium necessary for muscle contraction
has end chambers (terminal cisternae) attached to t-tubules

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17
Q

What is a triad?

A

one t-tubule and 2 terminal cisternae from 2 different SR

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18
Q

What does an action potential allow the cisternae and SR to do?

A

release calcium

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19
Q

Where do the terminal cisternae release calcium into?

A

the sarcoplasm

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20
Q

What are myofibrils?

A

overlapping myofilaments

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21
Q

What are myofilaments responsible for?

A

muscle contractions

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22
Q

Where do thin filaments attach to?

A

z-disc

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23
Q

Where do thick filaments attach to?

A

m-line

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24
Q

What is the sarcomere?

A

contractile unit of muscle

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25
Q

What is the A-band?

A

always the length of the thick filament

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26
Q

What is the H zone?

A

thick filaments only

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27
Q

What is the I band?

A

thin filaments only

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28
Q

Where does the sarcomere run to and from?

A

z-disc to z-disc

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29
Q

What is the zone of overlap?

A

both myofilaments overlap

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30
Q

What is a fascicle?

A

a bundle of muscle fibers

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31
Q

What surrounds a fascicle?

A

the perimysium

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32
Q

What covers the skeletal muscle as a whole?

A

epimysium

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33
Q

What covers individual muscle fibers?

A

endomysium

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34
Q

What controls the skeletal muscles?

A

nerves of the somatic system

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35
Q

What is the epimysium?

A

external collagen layer
connected to deep fascia
separates muscle from surrounding tissues

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36
Q

What is the perimysium?

A

surrounds fascicles
contains blood vessel and nerve supply to fascicles

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37
Q

What is the endomysium?

A

surrounds individual muscle fibers
contains capillaries and nerve fibers contacting muscle cells
contains myosatellite (stem) cells that repair damage

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38
Q

Where do the epimysium, perimysium, and endomysium meet?

A

at ends of muscles to form connective tissue

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39
Q

What is apneurosis?

A

typically connects muscle to muscle (sheet like)

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40
Q

How is tendon attachment described?

A

cord-like bundle

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41
Q

What is the sliding filament theory?

A

z-discs move toward m-line, increasing overlap between thin and thick filaments

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42
Q

What happens to the A zone in the sliding filament theory?

A

the width stays the same

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43
Q

What happens to the Z-discs in the sliding filament theory?

A

they move closer together

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44
Q

What happens to the H zone and I bands in the sliding filament theory?

A

they get smaller

45
Q

What happens to the zone of overlap in the sliding filament theory?

A

it gets bigger

46
Q

What is the plasma membrane impermeable to?

A

charged ions like sodium and potassium

47
Q

How do the ions get through the plasma membrane?

A

leak channels
gated channels

48
Q

How is an excitable membrane described?

A

potassium high inside cell
sodium high outside cell

49
Q

What does the electrical gradient do?

A

attracts ions of opposite charge

50
Q

Where do positively charged ions want to be?

A

inside the cell

51
Q

What is the charge of the cell at rest?

A

positive outside
negative inside

52
Q

What is the electrical and concentration gradient of potassium?

A

electrical gradient wants to go inside cell
concentration wants to go out

53
Q

What is the electrical and concentration gradient of sodium?

A

concentration gradient to go inside cell
electrical gradient to go inside cell

54
Q

What is a neuromuscular junction?

A

a synapse (where a neuron and a muscle fiber connect)

55
Q

What do neuron synaptic terminals contain?

A

vesicles containing Ach at the end of the neuron

56
Q

What is Ach?

A

a neurotransmitter

57
Q

What is a synaptic cleft?

A

the space between a neuron and a muscle

58
Q

What is the communication at the synapse?

A

action potential releasing neurotransmitter to make things happen

59
Q

What is the motor end plate?

A

contains Ach receptors

60
Q

What has to happen to initiate an action potential?

A

it has to reach the axon terminal

61
Q

What happens when the action potential reaches the axon terminal?

A

it opens calcium channels

62
Q

What happens when calcium enters the cell?

A

Ach is released from the vesicles via exocytosis

63
Q

What happens to Ach once released from the vesicles?

A

It diffuses across the synaptic cleft and binds onto Ach receptors (sodium channels)

64
Q

What kind of channels are the calcium channels?

A

voltage gated calcium channels?

65
Q

What kind of channels are the Ach receptors?

A

ligand-gated ion channels (sodium channels)

66
Q

What happens when Ach binds onto the Ach receptors?

A

Ach opens the channels
Sodium moves into the cell, initiating an action potential

67
Q

What happens to the sarcolemma sodium moves into the cell?

A

depolarizes

68
Q

What is tropomyosin?

A

on actin filaments
prevents actin-myosin interaction

69
Q

What is troponin?

A

Binds tropomyosin to actin
controlled by calcium

70
Q

What is the sarcomere function in excitation-contraction coupling?

A

t-tubules encircle the sarcomere near zones of overlap

71
Q

What causes thick and thin filaments to interact?

A

release of calcium from SR

72
Q

What is a crossbridge?

A

where thick and thin filaments connect

73
Q

What kind of channels are on terminal cisternae?

A

voltage-gated calcium channels

74
Q

What is the 1st step of excitation-contraction coupling?

A

activation of myosin head by ATP hydrolysis

75
Q

What is the 2nd step of excitation-contraction coupling?

A

myosin head binds to actin

76
Q

What is titin?

A

spring/coil that runs from ends of thick filaments to z-discs
dumps calcium back into SR
pushes z-discs away to return muscle fiber to shape

77
Q

How does a muscle fiber return to resting length?

A

elastic forces (titin)
opposing muscle contractions
gravity

78
Q

What causes rigor mortis?

A

ions pumps cease to function; ran out of ATP
calcium builds up in sarcoplasm
SR leaks calcium

79
Q

What is glycotic catabolism?

A

occurs in cytosol
anaerobic
2 ATP per glucose

80
Q

What is oxidative catabolism?

A

occurs in mitochondria
aerobic
34 ATP per glucose

81
Q

How does ADP become ATP again?

A

steals a phosphate from creatine phosphate in the presence of creatine kinase

82
Q

How does the muscle store glucose?

A

as glycogen for ATP production

83
Q

How does muscle generate ATP?

A

breaks down 6 carbon molecule into 2 three-carbon molecules (pyruvate and 2 ATP)

84
Q

What happens to pyruvate during ATP generation?

A

it becomes lactic acid and lactic acid acid stays in the muscle fiber or is put into the blood

85
Q

What happens when muscle runs out of oxygen?

A

It relies on glycolysis
pyruvic acid builds up and converts to lactic acid

86
Q

What does tension of a single muscle fiber depend on?

A

the # of cross bridges
the fiber’s resting length at the time of stimulation
the frequency of stimulation

87
Q

What is a twitch?

A

a single neural stimulation that produces a single contraction in response to a single batch of Ach binding

88
Q

What is tetanus?

A

repeated frequency of stimulus with no relaxation
max tension

89
Q

what is a type 1 muscle fiber?

A

slow to contract and slow to fatigue
contain myoglobin
more mitochondria, less myofibrils and contractile proteins
relies on O2 and ability to make ATP

90
Q

What is a type 2 muscle fiber?

A

contracts very quickly, fatigues quickly
less mitochondria, more myofibrils and contractile proteins
relies on glucose

91
Q

What happens when the motor unit is smaller?

A

the motor control is finer

92
Q

What is a motor unit?

A

a motor neuron and the muscle fiber or fibers it controls

93
Q

What is smooth motion?

A

increase tension by adding motor units until desired tension is reached for specific task

94
Q

When is max tension achieved?

A

when all motor units reach tetanus

95
Q

What is a hypotonic contraction?

A

no tension (flaccid)

96
Q

What is a hypertonic contraction?

A

contractures (brain inhibits motor neurons)

97
Q

What is an isotonic concentric contraction?

A

muscle shortens

98
Q

What is isotonic eccentric contraction?

A

muscle lengthens

99
Q

What is an isometric conctraction?

A

muscle stays the same length but changes tension

100
Q

What does endurance affect?

A

increases # of mitochondria and their efficiency
increases blood supply to muscles

101
Q

What happens when a muscle fatigues?

A

it relies on glycolytic metabolism
build-up of pyruvate to lactic acid

102
Q

What does lactic acid do to muscle?

A

damages the sarcolemma and SR
calcium leaks out
causes pain and muscle cramps
moves into the blood

103
Q

How does muscle recovery occur?

A

-needs oxygen and build up of ATP and creatine phosphate reserves
-heat moves into blood, vasodilates and releases into atmosphere
-calcium is pumped back into SR
-correction of lactic acid PH by exhaling CO2

104
Q

When is epinephrine (adrenaline) released?

A

during times of stress from adrenal glands

105
Q

What does adrenaline do?

A

increases duration and force of contraction for short time

106
Q

How does an action potential spread in cardiac muscle tissue?

A

through the intercalated discs

107
Q

What does cardiac muscle tissue rely on?

A

extracellular and intracellular calcium
relies on mitochondrial ATP production

108
Q

What makes smooth muscle tissue special?

A

it is not worried about tension and always has an active actin site for myosin
relies exclusively on extracellular calcium for contraction
no sarcomere

A&P 1 (12 decks)

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