Midterm 2: Chapters 1 & 10 Flashcards Preview

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Flashcards in Midterm 2: Chapters 1 & 10 Deck (107)
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1

What are the three types of muscle tissue?

- skeletal muscle
- smooth muscle
- cardiac muscle

2

_______: voluntary, skeleton.

skeletal muscle

3

_______: involuntary, hollow organs.

smooth muscle

4

_______: involuntary, heart.

cardiac muscle

5

the entire muscle is surrounded by and consists of?

- surrounded by epimysium
- consists of many bundles (fasciculi)

6

what is the fasciculi surrounded by and consist of?

- surrounded by perimysium
- consists of individual muscle cells (muscle fibers)

7

what is the muscle fiber surrounded by and consist of?

- surrounded by endomysium
- consist of myofibrils divided into sarcomeres

8

_________: fuses with tendon, conducts action potential, maintains pH, transports nutrients.

plasmalemma also referred to as the cell membrane.

9

_______: cytoplasm of muscle cell, has unique features: glycogen storage, myoglobin.

sarcoplasm

10

______: a protein inside the muscle cell that carries oxygen.

myoglobin

11

_________: a protein that carries oxygen within the blood system.

hemoglobin

12

_________: extensions of plasmalemma, carry action potential deep into muscle fiber.

transverse tubules (T-Tubules)

13

________: calcium (ca 2+) storage.

sarcoplasmic reticulum

14

_______: muscle -> fasciculus -> muscle fiber -> ? , sections known as sarcomeres.

myofibrils

15

______: basic contractile element of skeletal muscle, end to end for full myofibril length.

sarcomeres

16

what are the band parts of the sarcomeres referred to as?

~ a-bands: dark/blue stripes
~ I-bands: light/pink stripes
~ h-zone: middle of a-band
~m-line: middle of h-zone

17

what is the common boundary of the sarcomeres?

Z-disk (or Z-line)

18

______: show up lighter under microscope (red), I-bands contains only ?.

Actin (thin filaments)

19

Actin (thin filaments) actually composed of three proteins what are they?

- actin
- tropomyosin
- troponin

20

_____: contains myosin-binding site.

actin

21

_____: covers active site at rest.

tropomyosin

22

_____: anchored to actin, moves tropomyosin.

troponin

23

_____: two intertwined filaments with globular heads.

myosin (thick filaments)

24

______: protrude 360 degrees from thick filament axis, will interact with actin filaments for contraction.

globular heads

25

muscle fiber contraction starts with?

nervous system

26

____: innervates muscle fibers.

alpha-motor neurons

27

_____: single alpha-motor neuron + all fibers it innervates, more operating motor units = more contractile force.

motor unit

28

fibers contract through sequence of events:

"excitation contraction coupling"

29

What would the process of a muscle contraction?

1. action potential (ap) starts in brain
2. AP carries at axon terminal, releases ACh
3. Ash crosses synapse, binds to Each receptors on plasmalemma
4. AP travels down plasmalemma, T-tubules
5. Triggers Ca 2+ release from sarcoplasmic reticulum
6. Ca 2+ enables actin-myosin contraction

30

When the action potential arrives at SR from t-tubule what happens?

- SR sensitive to electrical charge
- causes mass release of Ca 2+ into sarcoplasm

31

what happens when Ca 2+ binds to troponin on actin?

- at rest, tropomyosin covers myosin-binding site
- troponin-Ca 2+ complex moves tropomyosin
- myosin binds to actin, forming a cross-bridge. allowing a contraction to occur

32

how muscles create movement is the process of?

actin-myosin contraction

33

____: no actin-myosin interaction at binding site, myofilaments overlap a little.

relaxed state

34

type II fibers consist of?

type IIa and type IIx

35

type II fibers in general?

- poor aerobic endurance, fatigue quickly
- produce ATP through anaerobic pathways

36

what are the characteristics of type IIa fibers?

- more force, faster fatigue than type I
- short, high-intensity endurance events

37

what are the characteristics of type IIx fibers?

- seldom used for everyday activities
- short explosive sprints (100 m)

38

________: myosin head pull actin toward sarcomere center (POWER STROKE), filaments slide past each other, sarcomeres, myofibrils, muscle fiber all shorten.

contracted state

39

according to the sliding filament theory what happens after power stroke ends?

- myosin detaches from active site
- myosin head rotates back to original position
- myosin attaches to another site farther down

40

according to the sliding filament theory process continues until?

- z-disk reaches myosin filaments
- AP stops, Ca 2+ gets pumped back into SR

41

_______: most influential in determining percentage

genetic factors

42

_____: can induce small (10%) change in fiber type, IIx -> IIa

training factors

43

______: muscles lose type II motor units

aging

44

what would be the other predictors for athletic success, since fiber type is not the sole predictor?

- cardiovascular function
- motivation
- training habits
- muscle size

45

muscle fiber recruitment is also referred to as?

motor unit recruitment

46

what does "muscle fiber recruitment" mean?

when a motor unit is recruited, ALL of its fibers are activated

47

what is the method for altering force production?

- less force: fewer or smaller motor units (type I)
- more force: more or larger motor units (type II)

48

what is the recruitment order?

- smallest (type I) motor units
- mid sized (type IIa) motor units
- largest (type IIx) motor units

49

T/F ? Motor units are recruited in the same order each time.

true

50

________: order recruitment of motor units directly related to size of a-motor neuron

principle of orderly recruitment (size principle)

51

_______: muscle produces force and changes length, joint movement produced.

dynamic contraction

52

what are the two subtypes of muscle contraction?

concentric and eccentric

53

______:
- muscle shortens while producing force
- sarcomere shortens, filaments toward center

concentric contraction

54

______:
- muscle lengthens while producing force
- cross-bridges form but sarcomere lengthens
- Ex.) lowering heavy weight

eccentric contraction

55

______:
- muscle produces force but does not change length
- joint angle does not change
- myosin cross-bridges form and recycle, no sliding

static (isometric) contraction

56

the amount of force developed depends on?

- number and type of motor units activated
- size of the muscle
- frequency of stimulation of each motor unit
- muscle fiber and sarcomere length
speed of contraction

57

when more force is generated and more motor units are activated what happens to type II and type II fibers?

- type I motor units = less fibers = less cross-bridges = less force
- type II motor units = less fibers = less cross-bridges = more force

58

single motor unit can exert varying levels of force dependent on _____ of stimulation.

frequency

59

_____: contractile response to single electrical stimulus.

twitch

60

_____: consecutive stimuli for greater force.

summation

61

_____: continued stimulation resulting in peak force

tetanus

62

process of varying levels is?

rate coding

63

what is the length-tension relationship?

fibers have optimal length for force production
- optimal sarcomere length = optimal overlap of actin/myosin
> maximizes cross-bridge interaction
-too short or too stretched = little or no force develops

64

what is the speed-force relationship?

ability to develop force also depends on speed of contraction

65

_____: maximal force development decreases at higher speeds.

concentric

66

_____: maximal force development increases at high speeds.

eccentric

67

what is the sensory-motor integration?

process of communication and traction between sensory and motor systems
> sensory stimulation can give rise to motor response

68

_____:
- fastest mode of response
> impulse does not travel up to the brain
- instant, preprogrammed response to a given stimulus
- only one response is possible
- occurs before conscious awareness

motor reflex

69

specific reflexes that help control muscle function involving two special structures:

1. muscle spindles
2. Golgi tendon organs

70

what are muscle spindles?

- group of 4-20 small, specialized intramural muscle fibers
- different from normal (extrafusal) muscle fibers
- innervated by y-motor neurons
- sensory receptors for muscle fiber stretch

71

when stretched, muscle spindle sensory neuron stimulated ... ?

- synapse in spinal cord with an a-motor neuron
- triggers reflex muscle contraction
- prevents further stretch
- stretch reflex

72

what are the Golgi tendon organs?

- sensory receptor embedded in tendon
> 5 to 25 muscle fibers attached to each GTO
> sensitive to tension in tendon

73

when stimulated by excessive tension, Golgi tendon organs ... ?

- inhibit agonists, excite antagonists
- safety mechanism that prevents excessive tension in muscle/tendon
- reduce potential for injury

74

what should you know about "motor response" ?

- a-motor neuron carries AP to muscle
- AP spreads to muscle fibers of motor unit

75

_____:
- fewer fibers per motor unit
- extraocular muscles have innervation ratio of 1:15

fine motor control

76

_____:
- more fibers per motor unit
- gastrocnemius has innervation ratio of 1:2000

gross motor control

77

_____: fiber types not mixed within a given motor unit, either type I fibers or type II fibers

homogeneity of motor units

78

explain hypertrophy versus atrophy ...?

- increase muscle size leads to an increase in muscle strength
- decrease in muscle size leads to a decrease in muscle strength
- but the association is more complex

79

strength gains result from?

- altered neural control
- increased muscle size

80

according to the mechanisms of muscle strength gain what is neural control?

- strength gain cannot occur without neural adaptations
> strength gain can occur without hypertrophy
> property of neuromotor system, not just muscle

81

what are the factors that are important to strength gains?

- increase motor unit synchronization and recruitment
- decrease autogenic inhibition
- reduced coactivation

82

according to the mechanisms of muscle strength gain what is synchronization and recruitment?

- motor units generally recruited asynchronously; not all engaged at the same instant
- resistance training -> synchronous recruitment
- synchronous recruitment -> strength gains

83

_____ = more motor units fire at the same time
- improves rate of force development
- increases capability to exert steady force

synchronicity

84

_____: normal intrinsic inhibitory mechanisms
- e.g., Golgi tendon organs
- inhibit muscle contraction if tendon tension too high
- prevent damage to bones and tendons

autogenic inhibition

85

training can _____ inhibitory impulses
- muscle can generate more force

decrease

86

_____:
- coactivation of agonists, antagonists
- normally antagonists oppose agonist force
- ... may -> strength gain

reduced coactivation

87

_____: increase in muscle size.

hypertrophy

88

what are the two types of hypertrophy?

- transient hypertrophy and chronic hypertrophy (long term)

89

_____: (after exercise bout)
- due to edema formation from plasma fluid
- disappears within hours

transient hypertrophy

90

_____: reflects actual structural change in muscle

chronic hypertrophy (long term)

91

muscle hypertrophy is maximized by?

- high-velocity eccentric training
- disrupts sarcomere Z-lines (protein remodeling)

92

______ only training may limit muscle hypertrophy and strength gains.

concentric

93

fiber hypertrophy may occur as a result of?

- more actin, myosin filaments
- more myofibrils
- more sarcoplasm
- more connective tissue

94

resistance training leads to ______ in protein synthesis.

increase

95

(T/F) ? according to fiber hypertrophy muscle protein content is always changing, during exercise synthesis decreases, while degradation increases, after exercise synthesis increases while degradation decreases.

true

96

______: facilitates fiber hypertrophy
- natural anabolic steroid hormone
- massive doses of anabolic steroids + resistance training -> large increases in muscle mass

testosterone

97

_____:
- short-term increase in muscle strength
- neural factors critical in first 8 to 10 weeks
- due to increase voluntary ?

neural activation

98

_____:
- long-term increases in muscle strength
- ? major factor after first 10 weeks
- associated with significant fiber hypertrophy
- net increases protein synthesis takes time to occur

hypertrophy

99

atrophy and inactivity can lead to?

reduction or cessation of activity -> major change in muscle structure and function
- seen in: limb immobilization studies, detraining studies

100

what happens after a client or patient is immobilized?

- major changes after 6 hours
- lack of muscle use -> reduced protein synthesis
- first week: strength loss of 3 to 4% per day
-( decreased size/atrophy)
- ( decreased in neuromuscular activity)
- reversible
- (recover when activity is resumed)
- (but recovery period longer than immobilization)

101

detraining can lead to?

- decreases in 1RM
- strength losses can be regained (~ 6 weeks)
- new 1 RM matches or exceeds old 1RM

102

once training goal is met, maintenance resistance program prevents detraining such as?

- maintain intensity (most potent)
- reduced training frequency

103

according to fiber type alteration the training regimen may not outright change fiber type, but?

- type II becomes more oxidative with aerobic training
- type I become more anaerobic with anaerobic training

104

according to the resistance trading for special populations: children and adolescents what would be considered a myth(s)?

- unsafe due to growth plate injuries
- ineffective before puberty due to. lack of hormones.

105

according to the resistance trading for special populations: children and adolescents what would be considered the truth?

- safe with proper safeguards
- children can gain both strength and muscle mass
- EMPHASIZE PROPER LIFTING TECHNIQUE!

106

(T/F) ? weight lifting or resistance training will be beneficial for the older population.

true

107

how can weight lifting help benefit the older population?

- helps restore age-related loss of muscle mass
- improves quality of life and health
- helps prevent falls
increases in strength dependent primary on neural adaptations