Chapter 11: Muscular System Flashcards Preview

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Flashcards in Chapter 11: Muscular System Deck (123)
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91

40-50 stimuli per second produces what? describe

complete tetanus; muscle has no time to relax between stimuli

92

isometric contraction

producing internal tension; but external resistance causes it to stay at the same length or become longer (NO MOVEMENT)

93

concentric contraction

muscle shortens as it maintains tension

94

eccentric contraction

muscle lengthens as it maintains tension

95

ATP supply depends on availability of: (2)

oxygen
organic energy sources (glucose & fatty acids)

96

2 pathways of ATP synthesis? which yields the most ATP?

aerobic respiration (use oxygen) yields more ATP (36 per molecule) anaerobic fermentation (without the presence of oxygen)

97

For short intense exercises how is oxygen supplied?

via myoglobin for limited aerobic respiration

98

What enzymes are used by muscles for transfer of phosphate? (2)

myokinase (makes cyclic AMP)
creatine kinase (uses creatine phosphate)

99

What system is used for nearly all energy used for short bursts of intense activity?

phosphagen system

100

After the phosphagen system-> a muscle enters ___ ____ which uses ___ to produce _____. How many ATPs are gained?

Anaerobic fermentation; glucose ; lactic acid
2 ATPs per molecule

101

long term energy uses which synthesis pathway?

aerobic respiration

102

What happens during fatigue? (4)

-ATP synthesis decline as glycogen consumed
-ATP shortage; slows down Na-K pumps
-lactic acid lowers pH of sarcoplasm
-motor nerve fibers use up ACh

103

endurance? how is it determined?

ability to maintain high intensity exercise for more than 4-5 minutes; by one's max oxygen uptake

104

How can you "beat" fatigue? (2)

-taking oral creatine (increases level of creatine phosphate in tissue: increase speed of ATP regeneration)
-carbohydrate overload (extra glycogen packed in)

105

slow oxidative muscle fibers (3)

-slow twitch, red, type I fibers
-abundant in mitochondria, myoglobin
-adapted for aerobic respiration & fatigue resistance

106

fast glycolytic muscle fiber

-fast twitch, white, type II fiber
-quick response, but not fatigue resistance

107

properties of cardiac muscle? (5)

-contraction w/ regular rhythm
-must contract in unison
-contractions must last long to expel blood
-must work in sleep
-tightly resistant to fatigue

108

Cardiac muscles are _____ and contain _____

striated; myocytes

109

in cardiac muscle, myocytes are joined at notched linkages called what?

intercalated disc

110

Cardiac muscles contain _____, so they can contract without need for nervous stimulation

built in pacemaker

111

How are damaged cardiac muscle cells repaired?

via fibrosis (not capable of mitosis-very little)

112

which synthesis is used almost exclusively by cardiac muscle?

aerobic respiration

113

Smooth muscle does not contain?

t-tubule or sarcomere structure

114

characteristics of smooth muscle (3)

-capable of mitosis & hyperplasia
-injured muscle can regenerate well
-some lack nerve supply

115

Describe myocyte structure in smooth muscle?

-fusiform shape
-no visible striations
-Z discs are replaced by dense bodies

116

Which type of smooth muscle is more widespread? does it require a nerve supply?what does it use

single unit smooth muscle; NO; gap junctions

117

Smooth muscle can contract in response to ____. Such as (3)

-chemicals
-hormones, CO2, stretch, oxygen deficiency

118

Does stimulation mean contraction in smooth muscle?

NO; relax arteries or contract bronchiles

119

What do the smooth single units contain?

autonomic nerve fibers varicosities

120

What are varicosities?

beadlike swellings that contain synaptic vesicles & few mitochondria