The Muscle System Flashcards

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2
Q

Musculoskeletal system

A

Comprised of muscles and skeltons

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3
Q

Muscles and skeletons are ____ that produce movment

A

effectors

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4
Q

3 types of vertebret muscle

A

skeletal, cardiac, smooth

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5
Q

Skeletal muscle involves

A

voluntary movement, breathing

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6
Q

Cardiac involves

A

beating of the heart

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7
Q

Smooth muscle

A

involuntary, movement of internal organs

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8
Q

What does it mean when skeletal muscles are “striated”

A

they have “strips” of muscle cells

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9
Q

skeletal muscle cells are called

A

muscle fibers

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10
Q

Muscle fibers are extremely ____, _____ cells

A

large - multinucleated

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11
Q

Skeletal muscles form by _____ of _____

A

fusion of embryonic myoblasts

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12
Q

One muscle consists of many _____ bundled together by connective tissue

A

muscle fibers

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13
Q

Each muscle fiber has several ______

A

myofibrils

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14
Q

Myofibrils consist of

A

bundles of actin and myosin filaments

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15
Q

The contractile proteins

A

Actin and myosin

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16
Q

Actin are ____ filaments

A

thin

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17
Q

Myosin are ____ filaments

A

thick

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18
Q

Sarcomere

A

overlapping actin and myosin filaments

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19
Q

Each myofibril consists of repeating units called

A

Sarcomeres

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20
Q

Titin and what does it do?

A

the largest protein in the body that holds bundles of myosin filaments in place

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21
Q

Describe the “sliding filament mechanism”

A

myosin heads bind to specific sites on actin molecules to form cross bridges, then change conformation to cause the actin filments to slide 5-10 nm

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22
Q

During the sliding filament mechanism mysoin heads _____ to specific sites on ____ to form ______

A

bind; actin; crossbridges

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23
Q

Muscle contration is initiated by ______ from a ____ neuron at the ______

A

action potentials, motor neruon, neuromuscular junction

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24
Q

A motor unit

A

all the muscle fibers that are activated by one motor neuron

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25
Q

Muscle cells are inhibited or excited?

A

excited

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26
Q

the plasma membrane of the muscle cells can ____ action potentials

A

conduct

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27
Q

____ is released by the motor neuron at the ______ and opens _____ in the _______

A

ACH; neuromuscular junction; ion channels; motor end plate

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28
Q

The chemical synapse between a motor neuron and a muscle cell is

A

the neuromuscular junction

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29
Q

Action potentials move through fibers via

A

T-tubules (transverse tubules)

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30
Q

T-tubules descend into the

A

sarcoplasm (muscle fiber cytoplasm)

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31
Q

The sarcoplasm is

A

the muscle fiber cytoplasm

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32
Q

T-tubules run close to the

A

sarcoplasmic reticulum

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33
Q

The sarcoplasmic reticulum (SR) is

A

a closed compartment that surrounds every myofibril, the ER of muscle cells

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34
Q

the SR has ____ pumps

A

Ca2+

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35
Q

At rest here is a ____ concentration of Ca in the _____ of the SR

A

high concentration; lumen

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36
Q

An action potential will ____ Ca channels and Ca flows ______ of the SR and triggers the interaction of

A

open; out; action and myosin

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37
Q

Actin filaments also include

A

tropomyosin and troponin

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38
Q

3 subunits of troponin bind to ___,__,___

A

actin, tropomyosin, and Ca2+

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39
Q

At rest, _____ blocks binding sites on actin

A

tropomyosin

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40
Q

Troponin changes conformation when

A

Ca2+ is released and binds to it

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41
Q

Tropomyosin is bound to _____ and the twisting of it exposes ___ on actin

A

troponin; binding sites

42
Q

When ___ pumps remove Ca2+ from the sarcoplasm, ____ stops

A

Ca2+; contraction

43
Q

The cardiac muscle is also striated

A

True

44
Q

The cardiac muscle cells are ____ than skeletal muscle cells and have how many nuclei?

A

smaller; just one nucleus

45
Q

Cardiac muscle cells can withstand high pressures due to

A

branching and interdigitating

46
Q

What initiates and coordinates heart contractions?

A

pacemaker and conducting cells

47
Q

The heartbeat is generated by the heart muscle itself which means that it is

A

myogenic

48
Q

Heart transplantations are possible because

A

the autonomic NS modifies the rate of pacemaker cells, but isnt nescessary

49
Q

Cardiac and smooth muscle cells are arranged in

A

sheets

50
Q

cells in cardiac sheets are in electrical contact vi

A

gap junctions

51
Q

the cell sheets allow an action potential to ___ to all others in the sheet, so the heart can _____ contractions

A

spread; sync

52
Q

what connects the cytoplasm of two neighboring cells and allow electrical communication?

A

gap junctions

53
Q

Gap junctions in cell sheets allow ___ and ____ muscle cells to contract simultaneously

A

cardiac and smooth

54
Q

The simplest muscle cells

A

smooth muscle cells

55
Q

smooth muscle cell contains just

A

one cell/nucleus

56
Q

They are “smooth” muscle cells because

A

actin/myosin are not as regularly arranged

57
Q

Smooth muscle cells are under ____ control

A

Autonomic NS control

58
Q

What is a twitch

A

minimum unit of contraction by skeletal muscle

59
Q

Twitch is measured in terms of

A

tension

60
Q

A _____ generates a twtich

A

a single action potential

61
Q

If action potentials are close together the twitches add up.

A

True

62
Q

How do twitches build up?

A

calcium pumps can’t clear out all the Ca from the sarcoplasm before the next one comes and it piles up

63
Q

Tetanus is

A

when APs are so frequent that this is always calcium in the sarcoplasm

64
Q

How long a muscle fiber can sustain tetanic contraciton depends on ____ supply

A

ATP

65
Q

What is needed to break actin/mysoin bonds and “re-cock” the heads?

A

ATP

66
Q

To maintain contraction…

A

actin-myosin bonds have to keep cycling

67
Q

3 systems for muscles to obtain ATP

A

Immediate, glycolytic, oxidative

68
Q

Immediate system

A

uses pre-formed ATP and creatine-phosphate

69
Q

Glycolytic system

A

metabolizes carbs to pyruvate and lactic acid; anaerobic

70
Q

Oxidative system

A

carbs and fatty acids to H2O and CO2 (aerobic)

71
Q

Creatine phosphate (CP) ___ energy in a ____ bond that can transfer to ADP

A

stores energy in a phosphate bond

72
Q

ATP+CP is the ____ system

A

immediate

73
Q

The ATP from the ____ immediate system is exhusted within seconds; ___ yield of ATP

A

immediate; low yield of ATP

74
Q

In the glycolytic system, enzymes are in the _______

A

sarcoplasm/cytoplasm

75
Q

ATP generated during glycotic system is not directly available to myosin

A

False, its FAST!

76
Q

Is glycotic system aerobic or anaerobic?

A

Anerobic

77
Q

Glycotic system has a ___ ATP yild

A

Low as well

78
Q

Immidate and glycolytic systems provide energy for _____

A

less than one minute

79
Q

Oxidative phosphorylation occurs in the

A

Mitochondria

80
Q

Oxidative method makes _____ of ATP and is ____

A

a lot of; aerobic (CO2) is created

81
Q

ATP must ____ from the mitochondria to the ____ in the cytoplasm, therefore it is ____ than the other two systems

A

diffuse; mysoin; slower

82
Q

Two main types of skeletal muscle fibers

A

slow and fast twitch

83
Q

The slow twitch muscle fibers are the _____ or ___ muscle

A

oxiative or red

84
Q

ST fibers contain ____ which is the oxygen binding protein

A

myoglovin

85
Q

ST fibers contain many _____ and _____

A

Mitochondria and blood-vessels

86
Q

In ST fibers, max tension develops ____ and is _____ to fagitue

A

slowly; highly resistant

87
Q

ST fibers have reserves of what?

A

Glycoghen and fat

88
Q

ST fibers and produce ATP as long as ____ is avaialble

A

oxygen

89
Q

ST fibers are good to use with ____ excercise

A

aerobic exercise

90
Q

Fast-twitch muscle fibers are ____ or ___ muscles

A

glycolytic/white

91
Q

Complete opposite of ST fibers - _____ mitochonrdria, blood vessels, myoglobin

A

LITTLE

92
Q

FT fibers develop max tension ____ and fatigue ______-

A

faster and faster

93
Q

FT fibers can replenish ATP for prolonged contraction

A

FALSE

94
Q

What determines muscle strength and endurance?

A

The proportion of ST and FT fibers

95
Q

Genetic heritage plays a role in determining

A

Proportion of ST and FT fibers

96
Q

Training a muscle can alter muscle properties

A

True (to an extent)

97
Q

Anerobic exercise increases muscle _____.

A

Strength

98
Q

What happens when a muscle gets stronger?

A

new actin/myosin filaments form, muscle gets JACKED

99
Q

Aerobic exercise increases muscle _____

A

Endurance

100
Q

What happens when muscle gains endurance?

A

oxidative capacity is enhanced due to the increase in mitochondria, blood vessels, myoglobin, and enzymes