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Histology Exam 2 - Brendan > Muscle > Flashcards

Muscle Flashcards

1
Q

Muscle is surrounded by a dense connective tissue layer called ____

A

epimysium

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2
Q

muscle consists of _____ ______ bundles (Fascicles) surrounded by ______

A

muscle fiber

perimysium

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3
Q

_____ ______ ______ consist of individual multinucleated muscle fibers 10-100 um wide and up to 30 cm long.

A

Muscle fiber bundles

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4
Q

Muscle cells are surrounded by a ______ _____ and reticular fibers that make up the _____

A

basal lamina

endomysium

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5
Q

endomysium contains _____ that supply blood to the muscle fiber

A

capillaries

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6
Q

Complete the “muscle flow chart”

  1. _____ (surrounded by epimysium)–>
  2. ______ (surrounded by perimysium) –>
  3. _____ (Surrounded by endomysium) –>
  4. _______
  5. _______
A 
muscle
muscle fiber bundle aka fascicle
muscle fiber aka muscle cell
myofibril
myofilament
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7
Q

_____ cells are infrequent small cells found between the sarcolemma and basal lamina. They are stem cells that can proliferate after trauma and form new _____

A

satellite

myoblasts

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8
Q

In LM with H and E staining, A bands stain _____ while I bands are _____. A dark ___ line may be seen bisecting the I band.

A

dark
light
Z

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9
Q

The _____ is the functional unit of contraction, and runs from ____ to _____

A

sacromere

z-disk to z-disk

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10
Q

The ____ _____ is in the middle of I bands and is where actin filaments insert

A

Z disk

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11
Q

Skeletal muscle has a well developed _____ system.

A

Triad

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12
Q

The inner portion of the triad in skeletal muscle is an infolding of the plasma membrane called a ___ ____. The 2 triad side portions are modified smooth ER called ____ ______

A

T-tubule

sarcoplasmic reticulum

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13
Q

The triad system in skeletal muscle is found in the ___ ____ band junction

A

A and I

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14
Q

The interaction between nerve axon and muscle is called the ____ ____ ____ (aka myoneural junction)

A

motor end plate

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15
Q

Axon loses myelin sheath near the muscle cell, but ____ ____ still cover the axon

A

schwann cells

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16
Q

At the motor end plate, the axon and schwann cells (aka teloglia) basal lamina fuse with the ____ _____

A

muscle fiber

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17
Q

Axon terminals contain ____ which diffuses across the synaptic cleft and binds to receptors in ____ _____ of the sarcolemma

A

acetylcholine

junctional folds

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18
Q

The nerve and the muscle fibers it innervates is called a ____ _____

A

motor unit.

a single axon can innervate multiple muscle fibrs

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19
Q

____ ____ binds to the pre-snyaptic membrane, blocking ACH release

A

botulism toxin

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20
Q

Both the _____ _____ autoantibody and ______ bind to ACH receptors

A

myasthenia gravis

curare

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21
Q

Mysathenia gravis contains antibodies that block ____, leading to _____ ____ _____

A

acetylcholine

progressive muscle weakness

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22
Q

The action potential generated at the motor end plate is propagated along the _____ and is carried into myofirbils by the ____ __ _____ system (located at junction of A and I band) that is continuous with the myofibril _____

A

sarcolemma
transverse t tubule
sarcolemma

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23
Q

Depolarization of the T-tubule system causes release of ____ from ____ ______ of the sarcoplasmic reticulum

A

Calcium

terminal cisternae

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24
Q

The release of Ca causes conformational changes in troponin-__ that mediate the interaction of actin and ____, causing muscle contraction

A

C

myosin

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25
Q

___ fibers are Type 1 and slow twitch. They have ____ myoglobin content and _____ mitochondria. They are fatigue _____. They stain strongly for mitochondrial enzymes such as _____ ______

A 
red
high
numerous
resistant
succinate dehydrogenase
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26
Q

White fibers are type __ and ____ twitch. They have _____ myoglobin and mitchondria content, but have more stored ______ than red fibers. They also have higher ____-_____ than Type 1

A

2, fast
lower
glycogen
myosin ATPase

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27
Q

_____ controls fiber type differentiation.

A

innervation

ie, a red fiber can be changed to a white by denervating and replacing with nerve from white fiber

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28
Q

____ _____ are sensory receptors that run parallel with the main muscle fibers. They sense changes in ____ _____

A 
muscle spindles
muscle length (ie stretch receptors)
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29
Q

Muscle spindles contain modified muscle fibers called ____ fibers and neuron terminals in a fluid filled CT capsule.

A

intrafusal

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30
Q

The nerve terminal discharge rate _____ as the sensory ending is stretched. The nerve terminal has a ______ ending

A

increases

annulospiral

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31
Q

There are 2 types of intrafusal fiber: _____ _____ and ____ _____

A

nuclear bag and nuclear chain

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32
Q

After muscle injury, ____ transcription factor in combination with ___ _____ ____ induces proliferation of satellite cells (quiescent myoblasts).

A

myoD

hepatocyte growth factor (HGF)

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33
Q

In rigor mortis (after death), muscle cell membranes become ____ permeable to Ca. This promotes the cross-bridge attachment between ___ and ____.

A

more

actin and myosin

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34
Q

Rigor mortis–msucle fibers contract while Ach and ATP are present or until fully contracted. Muscles use ATP to pump ____ out of the cells, and once the ATP is used up, the actin and myosin proteins will stay ____ until decomposition

A

calcium

linked

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35
Q

Muscle atrophy is due to disuse and is caused by a reduction in _____ _____ _____

A

muscle fiber size.

the number of muscle fibers doesn’t change

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36
Q

Myofirbils consist of myofilaments that contain 4 main proteins:

A

actin, tropomyosin, troponin (thin)

myosin (Thick)

37
Q

____ is an elastic protein that connects myosin to Z-disk. It acts like a spring to keep ____ filaments centered in the sarcomere

A

titin

myosin

38
Q

____ is an INELASTIC protein attached to the Z-disk that runs parallel to actin

39
Q

___ is a mysoin binding protein that holds myosin filaments in register at the M-line

40
Q

__ _____ is a myosin binding protein that functions similarily to myomesin

41
Q

___ ___ bundles actin filaments into parallel arrays and anchors them to the Z-disk

A

alpha actinin

42
Q

____ is an IF that helps bind myofibrils to each other. It also encircles the Z disk. It is linked to each other by _____

A

desmin

plectin

43
Q

_____ is an actin binding protein that anchors muscle membrane proteins to actin. It

A

dystrophin

it is ABSENT in duchenne muscular dystrophy

44
Q

The _ ____ is the only band that contains thick filaments. It also contains thin myofilaments

45
Q

the _ band consists of thin myofilaments attached to the Z disk that extend to the A band.

46
Q

the _ band contains myosin (with no heads) and ____ ____ that catalyzes ATP formation from ADP and phosphocreatine

A

H

creatine kinase

47
Q

The _ ____ is a region of myomesin linking with myosin. It is located within the H band

48
Q

The _ ____ is the attachment region of thin filaments that contains __ _____

A

Z disk

alpha actinin

49
Q

Polymerization of actin in vivo is regulated by _____ and ____ and other cytosolic proteins

A

thymosin

profilin

50
Q

_____ is an elongated protein dimer that lies in grooves of the actin helix

A

tropomyosin

51
Q

Tropomyosin molecoule binds 3 troponin (Tn) peptides:
Tn-_ binds the Tn complex to tropomyosin
Tn-_ with tropomyosin inhibits the binding of actin to myosin
Tn-_ is the calcium binding subunit

52
Q

Binding of Calcium to the Tn-C subunit releases the TnI tropomyosin inhibition of actin activation of ___ ____

A

myosin ATPase

53
Q

___-_____ is a heat shock protein that protects desmin from stress-induced damage

A

alphabeta-crystallin

54
Q

____ reinforces and stabilizes the sarcolemma during contraction by linking the cytoskeleton with the ECM. Defective or lack of this protein disrupts sarcolemma and Ca entrance into the cell, leading to ____ ____ ____

A

dystrophin
muscle fiber necrosis

(ie this is duschennes muscular dystrophy)

55
Q

________ (aka limb-girdle muscular dystrophies) are mutations in genes for sarcoglycans, which disrupts the association of sarcolemma with ____

A

sarcoglycanopathies

ECM

56
Q

Myosin is the thick myofilament. It is both a ____ ____ and a ____ ____ ____

A

globular enzyme

fibrous structural protein

57
Q

Myosin consists of ___________ and ________

A

2 identical heavy and 2 pairs of light chains

58
Q

___ ____ contains the ATP and actin binding region

A

heavy meromyosin

59
Q

In striated muscle, myosin forms ____ ____

A

bipolar filaments

60
Q

muscle contraction–Ca released from the SR after membrane depolarization binds to the __-__ subunit of troponin

61
Q

Binding of the Tn-C unit with calcium causes a configuration shift of ____ and moves the tropomyosin molecoule deeper into the actin helix groove and exposes the ____ binding site on actin

A

troponin

myosin

62
Q

myosin binds to actin and the energy yielding breakdown of ___ to ____ flexes the ____ head and actin thin filaments are pulled into the a-band.

A

ATP to ADP

myosin

63
Q

A new ATP molecoule binding the myosin head causes the release of the bond between ___ and ____

A

actin and myosin

After contraction

64
Q

Cardiac muscle consists of ___ (1/multiple) nucleus/nuclei ____ located in the cell

A

1

centrally

65
Q

Cardiac muscle fiber is composed of several cardiac muscle cells joined end to end by junctional zones called ___ ____

A

intercalated disks

66
Q

intercalated disks have a transverse portion which contains ____ ____ and ___ ___ that bind adjacent cells together

A

fascia adherens

macula adherens

67
Q

intercalated disks contain a transverse portion and a lateral portion that contains ___ ____ that ionically couple adjacent cells

A

gap junctions

68
Q

A hallmark of cardiac muscle is ___ _____ _____

A

branched muscle fibers

69
Q

Cardiac muscle has more ____ and extrafibrillar sarcoplasm than skeletal muscle

A

mitochondria

70
Q

In cardiac muscle, the T-tubules are larger than in skeltal muscle and are located at the level of the __ _____

71
Q

A ____ arrangement is more common in cardiac muscle

72
Q

cardiac muscle responds to injury by forming a ____ ____ ____ ____. Under normal conditions, cardiac muscle does/does not regenerate

A

fibrous connective tissue scar

does not

73
Q

In skeletal muscle, all Ca ions come from the SR. In hear muscle, Ca ions can come from the SR as well as ___ ___ via slow ion channels

A

extraceullar fluid

74
Q

After myocardial infarction, cardiocytes have a _____ cytoplasm and ____ nuclei

A

eisonophillic

pyknotic (whatever that means)

75
Q

after 3 days from an MI, ___ ___ infiltrate cardiac tissue

A

inflammatory cells

76
Q

smooth muscle cells are ____ shaped but may branch. They contain a single ____ oval nucleus with 1 or more _____.

A

spindle
central
nucleoli

77
Q

smooth muscle cells are surrounded by a ___ ___ and may secrete collagen and elastin

A

basal lamina

78
Q

2 smooth muscles cells in contact may form ___ ____ and interdigitations that facillitate electrical conduction

A

gap junctions

79
Q

the plasma membrane of smooth muscle cells contain numerous ____ on the surface and ____ ____ in cytoplasm that contain alpha actinin.

A

caveolae

dense bodies

80
Q

Single smooth muscle cells are myoepithelial cells of ____ origin, found around sweat, salivary, lacrimal, and mammary glands, as well as the iris and cilliary body of the eye. They are basket shaped cells which contain ____ that attach them to basal lamina.

A

ectodermal

hemidesmosomes

81
Q

In mammary glands, smooth muscle cells contract in response to _____ and in lacrimal glands, they respond to _____

A

oxytocin

acetylcholine

82
Q

smooth muscle cells of ____ origin are located in respiratory, circulatory, digestive, and reproductive tracts

A

mesodermal

83
Q

Smooth muscle does not contain _____. The functional equivalent of the Z-disk is ___ _____

A

sarcomeres

alpha actinin

84
Q

Smooth muscle cytoplasm contains bundles of thin filaments (actin and tropomyosin but not _____), IF (desmin and _____) and thick filaments (____)

A

troponin
vimentin
myosin

85
Q

If smooth muscle myosin is _____, it is completely soluble

A

dephosphorylated

86
Q

Smooth muscle contraction–when stimulated, calcium increases in the cytoplasm and complexes with ____

A

calmodulin

87
Q

The Ca-calmodulin complex activates ___ ____ ____ ____, causing myosin to unfold and form filaments, allowing it to interact with actin

A

myosin light chain kinase

88
Q

___ may also activate myosin light chain kinase

Histology Exam 2 - Brendan (6 decks)

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