Muscle Histology Flashcards

1
Q

3 main points of muscle

A
  1. Body movement
  2. Aggrates of special long cells for contrsction
  3. Actin and myosin
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2
Q

Thin myofilament, formed from globular ____ proteins

A

Actin filament

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3
Q

thick myofilament consisting of 200-300 ____ molecules

A

Myosin filament

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4
Q

cells do not have cross-striations

A

Smooth musle cells

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5
Q

cells have cross-striations

A

Striated Muscle cell

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6
Q

Striated Muscle cell

attached to bone, responsible for movement

A

Skeletal

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7
Q

Striated Muscle cell

restricted to soft tissues (tongue, pharynx, upper esophagus, lumbar part of diaphragm) no bones.

A

Visceral Striated

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8
Q

Striated Muscle cell

wall of heart and base of large veins that empty into the heart

A

cardiac

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9
Q

Skeletal muscles cells are ____

rich blood supply

A

Multinucleated(formed from fusion of myoblasts)

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10
Q

Lenght of skeletal muscle cell depeneds on what?

A

On muscle it makes up

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11
Q

Skeletal muscle cells are surroudned by what that aids in force transduction from muscle to tendon

A

Connective tissue

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12
Q

How are skeletal muscle connected to bone?

A

Via tendon

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13
Q

(inner most)
* CT surrounding individual muscle cells
* composed of reticular fibers, external lamina (basal lamina), and thin areolar tissue
* allows room for capillaries and nerve fibers essential for initiat muscle contraction.

A

Endomysium

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14
Q

thicker CT, surrounds and defines fascicles (functional bundles of muscle fibers)

A

Perimysium

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15
Q

(outer most) sheet of dense connective tissue which surrounds a collection of fascicles. surrounds entire muscle

A

Epimysium

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16
Q

Types of Skeletal Muscle Fibers

  • Fatigue resistant motor units
  • Large numbers of mitochondria and amounts of myoglobin
  • Endurance athletes

long term

A

Type I- Slow oxidative

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17
Q

Types of Skeletal Muscle Fibers

  • Fast-twitch, fatigue-resistant motor units
  • Generate high-peak muscle tension
  • Hockey players, mid distance 400-800m sprinters higher concentration.
A

Type IIa- fast oxidative

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18
Q

Types of Skeletal Muscle Fibers

  • Fast-twitch, fatigue-prone motor (fast) units
  • Fastest of all fiber types
  • Short-distance sprinters, weightlifters; higher levels of fast glycolytic fibers.
A

Type IIb fast glycolytic

sprinters

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19
Q

dark bands (myosin)

A

A band

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20
Q

light bands (actin)

A

I band

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21
Q

anchor for actin

A

Z line

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22
Q

only myosin, no actin

A

H band

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23
Q

middle of sarcomere

A

M line

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24
Q

Each sarcomere in contraction myosin filament stay stable in center, thick filament slide over thin filament and bring ____ closer together.

A

Z line

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25
Q

molecule that polymerizes to form double-stranded to form F-actin

A

G actin

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26
Q

filament in the groove of F-actin 2 in double helix.

A

Tropomyosin

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27
Q

What doe tropomyosin do ?

A

Masks myosin binding site at rest, doesnt allow actin ot bind, prevents muscle contraction

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28
Q

3 parts of troponin complex

A
  1. TnC; bind Ca+
  2. TnT; bind tropomyosin
  3. Tn; bind actin
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29
Q

What does the **binding of calcium on TnC **of the troponin complex do?

A

Moves the tropomyosin out of way allowing myosin and actin to ineract and contract. Calcium is very important for muscle contraction

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30
Q

actin capping protein sit at end of actin filament and acts as a cap.

A

Tropomodulin
* maintains + regulate actin filiment lenfh preventing unwinding & degredation

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31
Q

Acts as a molecular ruler and adds stability to thin filaments (actin)

A

Nebulin

lack of would resilt in diff size actin

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32
Q

3 parts of myosin thick filament

A
  1. Tail
  2. Lever arm
  3. Head
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33
Q

intertwin to form thick myosin filament

A

Tail

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34
Q

important in movment of thick filament andallow actin to slide over myosin

A

Lever arm

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35
Q

important in grabbing onto acitn, hydrolyzing atp, and forming connection btwn myosin and actin for muscle contraction. Contain actin binding site and ATP binding site.

A

Head

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36
Q

zone in the M-line that has no myosin heads

A

bare Zone

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37
Q

____ shape allow consistent smooth contraction smooth sliding of actin filment onto myosin filament

A

Spiral

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38
Q

Acessory protien

  • prevents excessive stretching of the sarcomere
  • One of larget portien in body
A

Titin

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39
Q

Acessoru {protems

attach titin to Z-line

A

A-actin

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40
Q

Acessory protiens

forms stabilizing cross-links between myofibrils

A

Desmin

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41
Q

Acessory protiens

attach titin to M-line
* Titin stretch from M line to Z line, prevent over stretching.

A

M-line protiens

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42
Q

Acessory protiens

links laminin to actin filaments.
* Important for transfer of contraction form indv sarcomere out into connective tissue for muscle contraction
Lack of linkage will result in no mvmt in muscle.

A

Dystrophin

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43
Q

mutation in dystrophin protein.

Lose ability of transduction of muscle contraction from sarcomere to CT

A

Muscular dystrophys

44
Q

X-linked recessive trait
* primarily affects boy
* Onset is between 3 and 5
* Lose the ability to walk by age 12 and need a respirator by age 20

A

Duchenne muscular dystrophy

45
Q

similar to DMD but progression is much slower
* Onset 3-5 but progression much slower
* Due to mutation in dystrophine gene being different.

A

Becker muscular dystrophy

46
Q

Muscle Contraction

5 steps pf muscle contraction

A
  1. Attachment
  2. release
  3. Bending
  4. Force Generatation
  5. Reattachemnt

Duration of each stage depends on muscle type

47
Q

Muscle Contraction

Activation from CNA causes release of what?

A

Release of AcH which tavles via nerve to muscle cell and attaches

48
Q

Muscle Contraction

Attachment of AcH to muscle cell result in what?

A

Depolarizatio of cell and release of Ca+ ions

49
Q

Muscle Contraction

Release of Ca ions causes hwat?

A

Ca+ ions wil bind to TnC and moving tropomyosin from groove alowing **myosin head to acess to actin **

50
Q

Muscle Contraction

When ATP binds to myosin head what occurs?

A

Myosin head releases causingzone of hydroxylationo of ATP to ADP bending the myosin head

51
Q

Muscle Contraction

Mysoin head reaches and binds___

A

Binds actin, dumping phosphate off= muscle contraction.

52
Q

what 2 components are necessary for muscle contraction?

A

Calcium and ATP

53
Q

When does muscle contraction cycle end?

A

Muscle cell repolarized by removal of Ca+ and tropomyocin back to block

54
Q

____ regulation is key to contraction and relaxation
Needed to move tropomyosin out of the way for

A

Calcium

55
Q

Calcium reservoir
Most important calcium storage

A

Terminal cisternae

56
Q

____ carries depolarization signal into muscle and initiates release of calcium

A

T-tubules

57
Q

Lack of t-tubuled and cisternae would result in what?

A

Bad muscle contraction because depolarization would only occur on surface cells.

58
Q

the connection between nervous and muscular systems

A

Neuromuscular junction

59
Q

is the neurotransmitter

A

AcH

60
Q

Presence of ____ will help terminate signal for muscle contraction

A

AChE (acetylcholine esterase)

Toxins prevent AchE over contraction of muscles

61
Q

Lack of AChE results in what 3 things?

A

Prolonged contraction

62
Q
A
63
Q
  • Transmits information about muscle stretch
  • Located within muscle
  • Overactivation, inhibitory signal to spinal cord and shut down what is causing overstreach of muscle.
  • Stretching resets muscle spinldles to improve flexibility.
A

Muscle Spindles

64
Q
  • Monitor muscle tension and force of contraction
  • Located within tendon
  • Look at development of force, designed toshut down muscle if too much force produced, to protect from tearing muscle off the bone.
  • Sends inhibitory singal to spinal cord to shut down m. force generation
A

Golgi Tendon Organs

65
Q

what two things protect muscle from over generation of force and stretch.

A
  1. Muscle Spindle
  2. Golgi Tendon Organs
66
Q

?

A

Cardiac Muscle

67
Q
  • Striated muscle
  • intercalated discs
  • Fibers arranged end to end and branched
  • Single nucleus
A

Cardiac muscle

68
Q

specialized attachment sites between adjacent cells

A

Intercallated discs

69
Q

Contain atrial and brain natriuretic factor (ANF and BNF)
* Diuretics which inhibit renin and aldosterone secretion

A

Atrial granules in atrac cardica m. cells

70
Q

released in cases of conjestive heart failure with stress of atria and ventricle muscle, cells degranulate and release

A

ANF and BNF

71
Q

Cardiac muscle cells have many of what 2 things?

A
  1. Mitochondria
  2. Glycogen storage granules
72
Q

compoent of intercallated disc

site where thin filaments anchor to the plasma membrane this is how muscular contraction goes to thin to think filamanets sliding.

A

Fascia Adherens

73
Q

compoent of intercallated disc

bind individual cells together

A

Maculae adherens

74
Q

compoent of intercallated disc

provide ionic continuity between adjacent cardiac muscle cells, help with coordination of contraction.

A

Gao junctions

75
Q

Cardiac muscle contraction have longer?

A

Longer lasting membrane depolarization

76
Q

What is the purpoe of delayed depolarization in cardiac muscle cells?

A

causes delay from star of depo, to initiation of contraction
* allow time for more Ca to build ip
* Pause btwn atria and ventricular contraction

77
Q
  • Specialized cardiac conducting cells
  • Exhibit spontaneous rhythmic contraction no ext. imput required.
  • Resting 100bpm
A

Purkinje fibers

78
Q

Explain para vs symp stimulation of perkinji fibers

A
  • Para= slow heart rate, decrease impulse freuqency
  • SYM= increaase impuse frequency
79
Q
  • Ischemic event in the myocardium, no blood to area.
  • Localized injury replaced muscle cels with fiborous connecitve tissue
A

Myocardial Infarction

80
Q

Confirmation of suspected ____ due to blood markers TNL and TnT

A

MI

81
Q

Increase severity of MI leads to what?

A

Conjestive heart faliure

82
Q

fibrous connective repair tissue cannot contract causing more stretch in cardiac muscle

A

Conjestive heart faliure

83
Q
  • Bundles of sheets of elongated fusiform cells
  • Thin and thick filaments are loosely arranged; no stration
  • Connected via gap junctions
A

Smooth muscle

84
Q

?

A

Smooth Muscle

85
Q

Smooth muscle

calmodulin binding protein

A

Caldesmon

86
Q

Smooth Muscle

calcium binding protein

A

Calponin

87
Q

Smooth muscle thin filament contain what (2)?

A
  1. actin
  2. smooth muscle form of tropomyosin
88
Q

Smooth Muscle Structure have what?

A
  • Myosin with no bare zone
  • Side polar formation
89
Q

initiates the contraction cycle

A

Myosin light chain kinase

90
Q

regulates intracellular calcium concentration

A

Calmodulin

91
Q

structural component of dense bodies; where actin equivalents will bind to plasma membrane which allows for contraction of smooth m protein.

A

α-actini

92
Q
  1. Bundles of thin and thick filaments anchored dense body
  2. Contraction actin filaments slide in opposite direction shortering myofilament
  3. Corkscrew shape shorterning
A

Smooth muscle cell contraction

93
Q

Initiation of Smooth Muscle Contraction

stretching of vascular smooth muscle,

A

mechanical

94
Q

Initiation of Smooth Muscle Contraction

neural stimulation of smooth muscle

A

Electrical

95
Q

Initiation of Smooth Muscle Contraction

responses initiated by angiotensin II or vasopressin

A

Chemical

96
Q

Cardiac and skeletal muscle contracion initiated by what?

A

Only electical

97
Q
  • Calmodulin complex(troponin complex in cardiac and skeletal instead);
  • binds calcium
  • Activates release calcium, binds to calmodulim then binds myosin light chain kinsanse
  • Posphylation occurs opening actin binding protein,.
A

Smooth muscle contraction

98
Q

Smooth muscle contraction can be what?

A

maintained for long-time periods

slow, prolonged contraction

99
Q
  • Myosin head attached to actin is dephosphorylated which reduces ATPase activity
  • Prevents the myosin head from detaching and keeps muscle in contracted state

doesnt consume ATP

A

Latch state

sphincters!!

100
Q
A
101
Q
A
102
Q
A
103
Q
A
104
Q
A
105
Q

Smooth muscle in uterus during pregnancy

A

hyperplasia.