Lecture 10: Muscle Tissue I And II Flashcards

1
Q

3 types of muscle tissue

A

-skeletal
-cardiac
-smooth

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2
Q

Muscle fiber definition

A

-muscle cell
-myocyte

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3
Q

Functions of muscle fibers (3)

A

Produce force, movement and heat

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4
Q

Muscle fibers are surrounded by

A

Connective tissue

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5
Q

Sarcoplasm

A

Cytoplasm in muscle cell

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6
Q

What is contraction

A

Interaction of myofilaments

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7
Q

2 myofilaments in muscle fibers

A

Actin and myosin

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8
Q

Actin are __________ filaments

A

Thin

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9
Q

Myosin are __________ filaments

A

Thick

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10
Q

How/why do actin and myosin move (general)

A

-calcium causes conformational change
-actin and myosin move relative to each other (stack)

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11
Q

Which muscle tissue types are striated

A

Skeletal and cardiac

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12
Q

Which muscle type is non striated

A

Smooth

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13
Q

2 general Features of skeletal muscle

A

-larger cell diameter = greater force
-rich blood supply

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14
Q

Is skeletal muscle mononucleated or multinucleated

A

Multi

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15
Q

Skeletal muscle contains an abundance of

A

-mitochondria
-glycogen
-myoglobin

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16
Q

Myoglobin vs hemoglobin

A

Myoglobin has more oxygen

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17
Q

What is skeletal muscle usually attached to

A

Bone
-sometimes other muscles

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18
Q

Fascia

A

Connective tissue arranged in a sheet

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19
Q

Fascicle definition

A

Bundles of muscle fibers

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20
Q

Muscle fiber definition

A

Myocyte (muscle cell)

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21
Q

Myofibrils definition

A

Long row of myofilaments

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22
Q

Organization of skeletal muscle (biggest to smallest)

A

Bone —> muscle —> fascicle —> muscle fiber —> myofibrils

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23
Q

3 layers surrounding skeletal muscle

A

-epimysium
-peri my sim
-endomysium

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24
Q

Epimysium

A

Surrounds entire muscle

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25
Q

Perimysium

A

Surround fascicles

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26
Q

Endomysium

A

Surrounds muscle cell/myocyte

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27
Q

Epimysium and perimysium are composed of what kind of structural protein

A

Type 1 collagen

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28
Q

Endomysium is composed of what structural proteins

A

Other types of collagen (not type 1)

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29
Q

What do striations result from in skeletal muscle

A

Overlapping myofilament arrangement

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30
Q

What 3 skeletal muscle striations can we see at the level of light microscopy

A

-A bands
-I bands
-Z disk

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31
Q

A bands appearance

A

Dark bands

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32
Q

I bands appearance

A

Light bands

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33
Q

Z disk aka

A

Z line

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34
Q

Z disk appearance

A

Dark line in I band

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35
Q

What striations get closer together in skeletal muscle during contraction

A

Z disks

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36
Q

What 5 skeletal muscle striations are visible at TEM

A

-I band
-A band
-Z disk
-H band
-M line

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37
Q

Sarcomere definition

A

Z disk to Z disk

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38
Q

What is the smallest contractile unit in skeletal muscle

A

Sarcomere

39
Q

Sliding filament theory

A

Z lines brought closer together as myofilaments (actin and myosin) slide past each other

40
Q

Do myofilaments change length

A

No

41
Q

Invaginations of the sarcolemma that cause depolarization and calcium release are called

A

T tubules

42
Q

Triad definition

A

2 terminal cisternae + 1 t tubule located at junction of the A and I bands

43
Q

Cisternae are

A

Flattened membrane found in smooth ER

44
Q

Motor unit is defined as

A

Motor neuron + muscle fibers it innervates

45
Q

Terminal bouton aka

A

Synaptic knob

46
Q

Skeletal muscle fiber contraction is similar to propagation of action potential in axon how?

A

All or none

47
Q

All or none principle of contraction in skeletal muscles

A

All will contract or none

48
Q

Neuromuscular junctions are basically just

A

Synapses

49
Q

Structures involved in skeletal muscle fiber motor innervation (3)

A

-axon terminal of motor neuron containing synaptic vesicles with ACh
-synaptic cleft
-sarcolemma of myocyte containing junctional folds and ACh receptors

50
Q

2 structures involved in skeletal muscle fiber sensory innervation

A

-muscle spindles
-golgi tendon organ

51
Q

Function of muscle spindles: skeletal muscle fiber sensory innervation

A

-non contractile
-proprioception

52
Q

Golgi tendon organ

A

-sensory innervation
-monitor changes in length and tension (keep track of how much muscle is contracting)

53
Q

Primary response of skeletal muscle to stress

A

Hypertrophy

54
Q

Response to stress: hypertrophy (how it works)

A

-Myocytes enlarge by adding proteins
-satellite cells fuse with muscle fibers

55
Q

What process is limited in skeletal muscle during stress response

A

Hyperplasia = adding new cells

56
Q

Because hyperplasia is limited, how does stress affect skeletal muscle

A

Scar tissue formed

57
Q

Rigor mortis

A

-after death
-lack of ATP prevents dissociation of actin and myosin
-so actin and myosin stuck in whatever position they were in (stiffness)

58
Q

Where is cardiac muscle located

A

Myocardium of heart and proximal portion of pulmonary

59
Q

Cardiac muscle features/appearance (2)

A

-striated
-Sarcomeres

60
Q

How cardiac muscle contractions are modulated (what system)

A

Autonomic nervous system

61
Q

How cardiac muscle contractions are propagated (by what)

A

Gap junctions

62
Q

Cardiac muscle: nucleus

A

-mononucleated
-centrally located

63
Q

Do cardiac muscle fibers branch

A

Yes

64
Q

Intercalated disks

A

-unique to cardiac muscle
-where intercellular junctions occur

65
Q

What structure allows cardiac muscle cells to stick together

A

Desmosomes

66
Q

2 portions of intercalated disk

A

-transverse
-longitudinal

67
Q

2 components/structures found in transverse portion of intercalated disk

A

-fascia adherens
-desmosomes

68
Q

components found in longitudinal portion of intercalated disk

A

-gap junctions

69
Q

Transverse vs longitudinal portion of intercalated disk (function)

A

-Transverse = stability
-Longitudinal = less mechanical stress

70
Q

How t tubules and sarcoplasmic reticulum are arranged in cardiac muscle fibers (vs skeletal)

A

Diad

71
Q

Where does diad occur in cardiac muscle fiber

A

Z disk

72
Q

How cardiac muscle responds to stress (3)

A

-negligible hyperplasia
-hypertrophy
-injury leading to cell death and fibrosis (scar tissue)

73
Q

Where is smooth muscle found

A

Hollow organs, blood vessels, dermis, respiratory passages

74
Q

What does smooth muscle produce themselves

A

their own CT matrix

75
Q

What kind of layers are smooth muscle often found in

A

Perpendicular

76
Q

Smooth muscle shape

A

Fusiform

77
Q

Smooth muscle nucleus (General)

A

Mononucleated, central

78
Q

What happens to smooth muscle nucleus during contraction

A

Corkscrew

79
Q

Is smooth muscle striated

A

No

80
Q

Does smooth muscle have sarcomeres, actin and myosin

A

-kind of sarcomeres
-yes, actin and myosin

81
Q

Does smooth muscle have t tubules

A

No

82
Q

Where is most calcium found in smooth muscle cells

A

Extracellular

83
Q

Caveolae

A

Membrane invaginations that facilitate intake of calcium

84
Q

Of the 3 kinds of muscles, which has the slowest contractions

A

Smooth muscle

85
Q

How are myofilaments arranged in smooth muscle and what is the function

A

-Crisscross pattern
-contraction of fusiform shape

86
Q

3 main components/structures of smooth muscle

A

-myofilaments
-nucleus
-dense body

87
Q

Dense body

A

-where actin is anchored
-similar function as Z lines (get closer)
-stabilized by intermediate filaments

88
Q

2 types of smooth muscle contraction

A

-multi unit
-single unit (unitary)

89
Q

Multi unit contraction: smooth muscle

A

-muscle functions as multiple units of cells
-each unit innervated by single ANS neuron
-no/few gap junctions

90
Q

Example of smooth muscle multiunit contraction

A

Iris, vas deferens

91
Q

Where are axon terminals located in multiunit contraction of smooth muscle

A

Connective tissue

92
Q

Single unit contraction: smooth muscle

A

-all cells contract together
-cells linked by gap junctions
-contractions initiated by mechanical/chemical stimulated, modulated by ANS
-slow, energy efficient contractions

93
Q

Examples of single unit contraction in smooth muscle

A

-uterus
-GI
-urinary tract