OS 203 2.2 Muscle Tissue - Sheet1 Flashcards

1
Q

A band - “A,” means?

A

anisotropic - birefringent in polarized light

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2
Q

what’s in the A band

A

thick and thin filaments except at H band (thick only)

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3
Q

I band - “I,” meaning?

A

isotropic - does not alter polarized light

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4
Q

bisects the I band, name means?

A

Z line, Zwischesheibe - between discs

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5
Q

light area bisecting the A band, name means? contains what?

A

H band, Heller (light), thick filament only

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6
Q

bisects H band, proteins? (3)

A

M line; myomesin, a-actinin, titin

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7
Q

attaches thick filaments at the center of the M line

A

myomesin

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8
Q

attaches thin filaments to the Z line

A

a-actinin

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9
Q

extends from M line to Z line; maintains central location of A band; prevents over-stretching. appearance?

A

titin; coiled appearance at the attached portion in the I band

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10
Q

inner surface of sarcolemma is coated with what? function?

A

dystrophin - protects muscle from stress during contraction

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11
Q

x-linked autosomal recessive mutation affecting the expression of dystrophin (unable to walk by puberty)

A

duchenne muscular dystrophy

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12
Q

sarcoplasm contains

A

glycogen (for anaerobic glycolysis) and myoglobin

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13
Q

continuation of SR with gated calcium release channels; reservoir of?

A

terminal cisternae; calcium ions and calsequestrin

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14
Q

continuation of sarcolemma; location in skeletal muscle; fxn

A

T tubule; A-I jxn; interiorization of action potential

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15
Q

myosin components

A

2 chains heavy meromyosin (HMM) with heads at A band, ATP-binding site; light meromyosin (LMM) with tail at H band

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16
Q

thin filament components (3)

A

F-actin, troponin, tropomyosin

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17
Q

F-actin is made of

A

2 strands G-actin (with myosin binding sites) wound around e/o

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18
Q

troponin portions (3)

A

TnC (binds Ca), TnI (inhibit actin-myosin, binds to actin), TnT (binds to tropomyosin)

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19
Q

remove this to expose the binding site

A

troponin-tropomyosin complex

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20
Q

remains unchanged during contraction

A

A band

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21
Q

motor neuron and all muscle fibers it innervates

A

motor unit / neuromotor unit

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22
Q

branches in the terminal ends of nerve axon attached to the myofiber

A

terminal bouton

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23
Q

large motor unit: how many innervated? examples?

A

~100 muscle fibers; back, biceps

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24
Q

small motor unit: how many innervated? examples?

A

~3-5 muscle fibers; eye, hand

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25
Q

motor end plate / myoneural jxn: neurotransmitter

A

acetylcholine

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26
Q

primary vs secondary synaptic cleft

A

primary: between axon and sarcolemma; secondary (subneural cleft?): deep folds in the sarcolemma

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27
Q

postsynaptic membrane contains

A

nicotinic acetylcholine receptors (ligand-gated Na+ channels)

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28
Q

disorder: antibodies developed against receptors for acetylcholine -> weakness and fatigue in eyes, fingers, respiratory muscles

A

myasthenia gravis

29
Q

red muscle //

A

red / type 1 / slow twitch oxidative

30
Q

white muscle //

A

white / type 2b / fast twitch glycolytic

31
Q

intermediate muscle //

A

intermediate / type 2a / fast twitch oxidative

32
Q

red vs white vs intermediate: fiber diameter

A

red small, white large, intermediate intermediate :))

33
Q

red vs white vs intermediate: color

A

red red, white white, intermediate pink hahahahaha

34
Q

red vs white vs intermediate: mitochondria

A

red many, white few, intermediate many (*oxidation!!)

35
Q

red vs white vs intermediate: myoglobin, capillary density

A

red rich, white few, intermediate intermediate :))

36
Q

red vs white vs intermediate: fatigue rate

A

red slow, white fast, intermediate intermediate

37
Q

red vs white vs intermediate: twitch rate

A

red slow, white fast, intermediate fast

38
Q

red vs white vs intermediate: glycogen content

A

red low, white abundant, intermediate intermediate

39
Q

red vs white vs intermediate: histochemical reaction

A

red - high NADH, succinate dehydrogenase; white - low both; intermediate - medium to high

40
Q

red vs white vs intermediate: fxn

A

red - steady power, endurance (marathon); white - explosive bursts (weight lifting, short sprint); intermediate - combination (long sprint)

41
Q

intensity of contraction is based on (3)

A

number of motor units innervated, kind of motor units stimulated, firing frequency of activated units

42
Q

repairs muscle fibers; location? appearance? only seen in? repair can be done only if?

A

bet plasmalemma & lamina; large nucleus scarce cytoplasm; in skeletal muscle only; only if basal lamina is intact!

43
Q

single celled embryologic cells that fused -> multinucleated skeletal muscle

A

myoblasts (syncytium)

44
Q

smooth: vesicular invaginations of plasmalemma; fxn (analogous to)

A

caveolae; aids in calcium uptake and release (analogous to T tubule system)

45
Q

smooth: where thin & intermediate filaments converge and attach directly/indirectly to sarcolemma; analogous to? contains what?

A

dense bodies; analogous to z line; contains alpha actinin

46
Q

contraction of smooth: release of (?) -> binds with (?) -> phosphorylates (?) -> reacts with (?)

A

Ca-calmodulin complex; myosin light chain kinase (MLCK) enzyme; phosphorylates light chain (myosin); reacts with actin

47
Q

unique about the contraction of smooth muscle

A

light chain (myosin) must be phosphorylated before it can react with actin

48
Q

unitary innervation: how does impulse travel? fibers contract as a unit called? location?

A

gap jxn; syncytial smooth muscle; visceral muscles & bv

49
Q

multiunit innervation: one nerve cell innervates many muscle fibers which can contract individually location? (3)

A

ciliary body (eyes), wall of large bv, male reproductive tract

50
Q

pigment observable in cardiac muscle

A

lipochrome? lipofuscin from residual bodies

51
Q

xs: skeletal vs cardiac

A

skeletal - polygonal outlines; cardiac - continuum of myofibrils interspersed with sarcosome

52
Q

skeletal vs cardiac: t tubule, sarcoplasmic reticulum

A

cardiac - wider t tubule but less numerous & less developed SR

53
Q

skeletal is to triad as cardiac is to what? components? location?

A

dyad = t tubule + flattened saccule (no terminal cisternae); found in Z line

54
Q

intercalated disc configuration; coincides w/?

A

stairway; Z line

55
Q

intercalated disc: 3 types of jxn

A

fascia adherens, macula adherens (desmosome), gap junction

56
Q

intercalated disc: fascia adherens fxn

A

anchoring sites for actin filaments

57
Q

intercalated disc: desmosomes fxn

A

binds cardiac cells together (prevents tearing apart when heart contracts)

58
Q

intercalated disc: gap jxn fxn

A

ionic continuity

59
Q

atrial vs ventricular muscle fibers: t tubules, granules

A

atrial - smaller & fewer T tubule; atrial natriuretic peptide (ANP) in secretory granules

60
Q

ANP released in response to? fxn? opposite to?

A

in response to high blood volume; reduce blood pressure by vasodilation & Na+ & H2O loss; opposite to aldosterone

61
Q

2 types proprioreceptors

A

muscle spindle, golgi tendon

62
Q

muscle spindle location

A

perimysium

63
Q

muscle spindle structure

A

intrafusal (modified striated) fibers within CT capsule witihin extrafusal fibers

64
Q

what exactly does the muscle spindle detect? what is it responsible for?

A

change in length of extrafusal fibers; for regulation of muscle tone via spinal stretch/myotactic reflex (patellar reflex)

65
Q

intrafusal vs extrafusal fibers

A

intrafusal - very few myofibrils

66
Q

nuclear chain fibers vs nuclear bag fibers

A

nuclei closely aligned; piled in central dilation

67
Q

golgi tendon location

A

junction of muscle and tendon

68
Q

golgi tendon structure

A

small bundle of encapsulated collagen fibers

69
Q

golgi tendon: what exactly does it detect?

A

changes in muscle tension or force of muscle contraction