Exam #3 chapter 9 (Histology & physiology) Part 3 Flashcards Preview

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Flashcards in Exam #3 chapter 9 (Histology & physiology) Part 3 Deck (113)
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1
Q

Types of skeletal muscle fibers

A

1) slow-twitch oxidative (SO) (Type I)
2) Fast twitch Oxidative Glycolytic (FOG) (Type IIa)
3) Fast twitch Glycolytic (FG) (Type IIb)

2
Q

what type of myoglobin content does slow-twitch oxidative (Type I) have?

A

high

3
Q

what type of myoglobin content does FOG (type IIa) have?

A

high

4
Q

what type of myoglobin content does FG (type IIb) have?

A

low

5
Q

does SO (type I) have many or few mitochondria?

A

many

6
Q

does FOG (type IIa) have many or few mitochondria?

A

many

7
Q

does FG (type IIb) have many or few mitochondria?

A

few

8
Q

what type of metabolism does type I fibers have?

A

high aerobic capacity, low anaerobic capacity

9
Q

what type of metabolism does type IIa fibers have?

A

intermediate aerobic capacity, high anaerobic capacity

10
Q

what type of metabolism does type IIb fibers have?

A

low aerobic capacity, highest anaerobic capacity

11
Q

what type of fatigue resistance does type I fibers have?

A

high

12
Q

what type of fatigue resistance does type IIa fibers have?

A

intermediate

13
Q

what type of fatigue resistance does type IIb fibers have?

A

low

14
Q

what type of myosin ATPase activity do all three skeletal muscles have?

A

type I is slow and type II a and b are fast

15
Q

what type of glycogen concentration do all three skeletal muscle fibers have?

A

type I is low and type II a and b are high

16
Q

what location are type I fibers most abundant?

A

generally in postural muscles and more in lower limbs than upper limbs

17
Q

what location are type IIa fibers most abundant?

A

generally in lower limbs

18
Q

what location are type IIb fibers most abundant in?

A

generally in upper limbs

19
Q

what is the function of type I fibers?

A

maintenance of posture and performance of endurance activities

20
Q

what is the function of type IIa fibers?

A

endurance activities in endurance-trained muscles

21
Q

what is the function of type IIb fibers?

A

rapid, intense movements of short duration

22
Q

what are some characteristics of slow-twitch muscle fibers (type I)?

A

contract slowly but fatigue resistant.

23
Q

since the myosin ATP kinase in Type I fibers are slow, what happens to the myosin heads?

A

they pivot slowly

24
Q

what is ATP generated by in type I fibers?

A

aerobic metabolism

25
Q

what are type I fibers surrounded by?

A

abundant capillaries

26
Q

what are some characteristics of fast-twitch (type II) fibers?

A

they contract quickly and fatigue quickly

27
Q

what does type IIa use for ATP generation?

A

both anaerobic and aerobic respiration

28
Q

what does type IIb use for ATP generation?

A

anaerobic metabolism

29
Q

what does the distribution of muscle fiber types vary between?

A

different muscles in an individual and between individuals

30
Q

what can exercise cause for different muscle fibers?

A

hypertrophy and some type IIa and type IIb to convert to the other

31
Q

what do skeletal muscles require a huge amount of for contraction?

A

ATP

32
Q

what type of muscle fibers would be used for sprinting?

A

type IIa

33
Q

what type of muscle fibers would a marathoner use?

A

type I

34
Q

what type of muscle fiber would weight lifting use?

A

type IIb

35
Q

since a muscle can hypertrophy in strength and endurance what can happen if a muscle is not used?

A

it can decrease or atrophy

36
Q

what type of respiration does slow-twitch fibers generally use and for what?

A

aerobic respiration to generate ATP

37
Q

what type of respiration does fast-twitch fibers generally use?

A

anaerobic respiration

38
Q

what type of fibers and methods does any muscle contraction use?

A

both fiber types and both methods of ATP generation

39
Q

what does anaerobic respiration do? (2) (QW)

A

1) quickly generate 2 ATP per glucose by glycolysis

2) will generate some lactic acid (lactate) with little oxygen available

40
Q

what can lactate be metabolized to?

A

pyruvate or glucose

41
Q

how is lactate metabolized to pyruvate or glucose?

A

by certain cells such as liver, heart, kidney, adipose tissue and skeletal muscle

42
Q

where is most of the lactate metabolized?

A

in the liver

43
Q

what does aerobic respiration do?

A

slowly generate 36 ATP per glucose

44
Q

what does aerobic respiration require?

A

oxygen

45
Q

what else can aerobic respiration use?

A

fats, amino acids or carbohydrates

46
Q

which type of respiration is more efficient?

A

aerobic respiration

47
Q

even though aerobic respiration is more efficient what is it not?

A

quicker, it takes longer

48
Q

at rest what do skeletal muscles use?

A

fatty acids and aerobic respiration

49
Q

at maximal contraction what do skeletal muscles use?

A

more anaerobic respiration

50
Q

what do cells not store large amounts of?

A

ATP

51
Q

what is creatine phosphate?

A

an energy storage molecule

52
Q

what does creatine phosphate do?

A

quickly generate an ATP when needed for muscle contraction (8-10 seconds)

53
Q

when is creatine phophsate created?

A

when a muscle is at rest from ATP

54
Q

at rest what is ATP produced by?

A

aerobic respiration

55
Q

what are small amounts of ATP used for during rest?

A

in muscle contractions that maintain muscle tone and posutre

56
Q

what is excess ATP used for during rest?

A

to produce creatine phosphate

57
Q

during exercise what is supplying the ATP

A

the ATP that’s already in the cell is used first but during moderate exercise aerobic respiration provides most of the ATP necessary for molecule contraction

58
Q

during times of extreme exercise what provides small amounts of ATP that can sustain muscle contraction for brief periods?

A

anaerobic respiration

59
Q

what can energy stores in creatine phosphate during exercise also be used to do?

A

produce ATP

60
Q

throughout times of exercise what provides energy for active muscle contraction?

A

ATP from all of these sources (4-6)

61
Q

when does muscle fatigue occur?

A

when muscles DON’T contract properly

62
Q

what can muscle fatigue occur from?

A

from a lowered pH (acidosis)

63
Q

what is a lowered pH in muscles due to?

A

lactic acid or ATP depeletion or decreased ATP production

64
Q

what is the biggest cause of lactic acid or ATP depletion?

A

Type II fibers

65
Q

besides lowered pH what are other causes for muscle fatigue?

A

1) oxidative stress
2) inflammation in heavily used muscles
3) psychological fatigue

66
Q

what is oxidative stress characterized by?

A

build-up of excess reactive oxygen species (ROS; free radicals)

67
Q

when muscle contraction beings what happens to respiration?

A

there is a small increase but less than required

68
Q

what does the small increase of respiration during contraction cause?

A

oxygen deficit

69
Q

after exercise is completed what happens to respiration?

A

there is an oxygen debt to be paid that requires increased respiration to restore pre-contraction conditions (recovery oxygen consumption)

70
Q

what is recovery oxygen consumption?

A

the elevated oxygen consumption that occurs after exercise has ended

71
Q

what the recovery oxygen consumption used for?

A

a portion is used to “repay” the oxygen deficit but most of it is used to support metabolic processes that restore homeostasis after it was disturbed.

72
Q

how long does recovery oxygen consumption generally last?

A

minutes to hours

73
Q

what does the time that recovery oxygen consumption lasts depend on?

A

on the individual’s physical conditioning and on the length and intensity of the exercise session.

74
Q

in smooth muscle what are thin filaments attached to?

A

dense bodies

75
Q

what are dense bodies in smooth muscle anchored in?

A

the plasma membrane

76
Q

what are dense bodies in smooth muscle interconnected by?

A

intermediate filaments

77
Q

how are the actin and myosin filaments arranged in smooth muscle?

A

they overlap

78
Q

how are the actin and myosin filaments organized?

A

as loose bundles instead of sarcomeres

79
Q

what happens with thin and thick filaments during contraction?

A

they slide

80
Q

what is different about smooth muscle vs. skeletal muscle? (4) (NLSC)

A

1) no T tubules
2) less developed sarcoplasmic reticulum
3) stores calcium
4) calcium comes from the sarcroplasmic retiuculum and across sarcolemma to cause contraction

81
Q

what type of contraction does smooth muscle have?

A

slow

82
Q

why is contraction slower in smooth muscle?

A

it’s a longer process

83
Q

what must calcium do first during smooth muscle contraction?

A

calcium must diffuse in the cell and out of the sarcoplasmic reticulum

84
Q

after calcium is diffused out of the sarcoplasmic reticulum what must it bind to?

A

calmodulin

85
Q

what does the binding of calcium and calmodulin have to active?

A

myosin kinase

86
Q

what does the activation of myosin kinase during smooth muscle contraction have to do?

A

attach a phosphate group to the myosin head before it can bind to actin

87
Q

what does smooth muscle no contain during muscle contraction that skeletal muscle does?

A

troponin and tropomyosin

88
Q

what is relaxation in smooth muscle?

A

prolonged or sustained

89
Q

during muscle relaxation in smooth muscle what must myosin phosphatase do?

A

remove a posphate from the myosin head

90
Q

what does removing a phosphate while the cross bridge is formed do in smooth muscle?

A

sustain a contraction in the latch state and relaxation occurs more rapidly

91
Q

what is the most common type of smooth muscle?

A

visceral smooth muscle

92
Q

where does visceral smooth muscle occur?

A

in the digestive, urinary and reproductive tracts

93
Q

what does the visceral smooth muscle that occur in the digestive, urinary and reproductive tracts appear as?

A

sheets in the walls of the hollow organs

94
Q

in visceral smooth muscle what is true of the fibers?

A

only a few are innervated and most are connected by gap junctions

95
Q

what does the gap junctions that connect most visceral smooth muscle allow?

A

the tissue to function as a unit

96
Q

what do some tissues have in visceral smooth muscle?

A

pacemaker cells

97
Q

what does pacemaker cells in some visceral smooth muscle do?

A

cause the tissue to contract periodically (autorhythmicity)

98
Q

what does stimulation by any signal cause in visceral smooth muscle?

A

causes entire tissue to contract

99
Q

what does contraction of a muscle depend on?

A

where the muscle is

100
Q

where does the other less common type of smooth muscle, multiunit smooth muscle found?

A

in the muscles inside the eye, the arrector pilli muscles and blood vessel walls

101
Q

what are some characteristics of multiunit smooth muscle? (4) (AINA)

A

1) arranged into motor units
2) innervated
3) no connected by gap junctions
4) allows for precise control of the smooth muscle

102
Q

what are some functional properties of smooth muscle that are not seen in skeletal?

A

1) some smooth muscle is autorhythmic
2) when smooth muscle is stretched quickly it tends to contract
3) when smooth muscle is stretched slowly it maintains a constant tension (smooth muscle tone)
4) the tension generated is constant over a large range of length

103
Q

why is the tension generated of smooth muscle constant over a large range of length?

A

there no sarcomeres

104
Q

what innervates smooth muscle?

A

the autonomic nervous system (ANS)

105
Q

what does the ANS neurotransmitters acetylcholien and norepinephrine cause in smooth muscle?

A

contraction or relaxation depending on the neurotransmitter receptor

106
Q

what do certain hormones stimulate during smooth muscle contraction?

A

oxytocin

107
Q

what is oxytocin used for?

A

stimulates contraction of uterine smooth muscle especially during childbirth

108
Q

what affects smooth muscle contraction?

A

many local chemical substances

109
Q

what are cardiac muscle cells connected by?

A

intercalated disks with gap junctions

110
Q

how is calcium moved in cardiac muscle?

A

it comes across the sarcolemma and out of the sarcoplasmic reticulum

111
Q

compared to skeletal muscle, what is true of cardiac muscle?

A

it contracts much longer than a skeletal muscle twitch

112
Q

unlike skeletal muscle what is true or contractions?

A

not every depolorization of the sarcolemma produces a contraction

113
Q

what can certain signals do in smooth muscle?

A

open calcium channels in the sarcolemma and cause a contraction without depolorizing the sarcolemma

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