kin 346 exam 1

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1

Which layer of connective tissue surrounds a single muscle fiber?

Endomysium

2

What is the function of the transverse tubules?

Deliver action potentials to myofibrils

3

What is the function of the sarcoplasm?

Glycogen and myogobin storage

4

What is the function of the sarcoplasmic reticulum?

Calcium delivery and storage

5

Which event immediately precedes/triggers the power stroke?

Release of inorganic phosphate (Pi) from myosin

6

Which event immediately precedes/triggers the binding of the myosin head with actin?

Tropomyosin lifting off of actin

7

Which event immediately precedes/triggers the removal of the myosin head from actin?

ATP binding to myosin head

8

Which event immediately precedes/triggers the re-cocking of the myosin head so that it can bind to actin?

Hydrolysis of ATP

9

What determines the order in which motor units are recruited?

The size of the motor neuron

10

What primarily explains the differences in contraction velocity between a Type I and Type II muscle fiber?

The type of myosin ATPase

11

What is the rate-limiting step for Chemo-Mechanical Coupling?

ATP Hydrolysis

12

What explains the Parallel Elastic Component of muscle tension?

Connectins and mysmiums

13

Why are Type 1 motor units recruited before Type 2 motor units?

Lower threshold potential because they are smaller

14

Of the two methods used to alter force production in a muscle, which method do small finer control muscles rely most on?

Rate Coding

15

Why do Type 2 Motor Units generate more force than Type I Motor Units?

More fibers per neuron

16

Why does the force of all fibers decrease as their velocity of shortening increases?

Unable to hydrolyze ATP fast enough.

17

Why does relaxation of a muscle fiber require ATP?

To pump calcium out of cytosol into the sarcoplasmic reticulum

18

What are we really testing in traditional 1-Rep Max (1-RM) testing?

Max concentric strength

19

Slow twitch fibers are not recruited for "fast" movements such as running.

True or False

False

20

What is the physiological advantage of being born with a high% of Type IIx fibers?

Faster shortening velocity at peak force

21

During continuous intense exercise, what is the primary energy substrate for contracting skeletal muscle?

Muscle glycogen

22

During continuous intense exercise, what is the primary energy substrate for contracting skeletal muscle?

Muscle glycogen

23

Inside the human body, which of the following has the largest available supply of energy?

Subcutaneous and visceral triglycerides

24

What does phosphorylation mean?

Add a phosphate

25

What does the enzyme Creatine Kinase do?

Removes a phosphate from Phosphocreatine

26

Which of the following increases Creatine Kinase activity?

Increased ADP concentration

27

Which of the following decreases Creatine Kinase Activity?

Increased ATP concentration

28

Which of the following is the synthesis of glycogen from glucose?

Glycogenesis

29

Where in the muscle fiber does Glycolysis occur?

Cytosol

30

Despite a series of 10-12 enzymatic reactions, if coming from a glucose molecule glycolysis yields only ___mol of ATP.

2

31

Muscle cells cannot share their stored CHO directly with other muscle cells because?

muscle lacks glucose-6-phosphatase

32

Muscle cells can share their stored CHO indirectly via the ___________ shuttle

Lactate

33

Which one of the following is NOT a fundamental benefit of lactate formation within a muscle cell during high intensity exercise?

The formation of lactate creates an ATP molecule

34

How does the Phosphagen Energy System "know" that it needs to activate and produce ATP?

Increasing ADP levels from ATP hydrolysis stimulates creatine kinase to phosphorylate an ATP.

35

Which of the following shuttles indirectly generates ATP from glycolysis?

Glycerol-phosphate shuttle

36
  1. Why must there be NAD to maintain the glycolytic flux of a muscle cell?

NAD available for reduction to oxidize glycerladehyde-3-phosphate

37

Where in a muscle cell do the Krebs Cycle and the ETC occur in?

Mitochondria

38

What by-product released during glycolysis, the conversion of pyruvate to Acetyl-CoA, and the Krebs Cycle gets shuttled to the ETC?

Hydrogen Ions

39

In the Electron Transport Chain, what is the energy released in the passage of electrons from complex to complex used for?

To pump protons into the outer mitochondrial compartment

40

In the Electron Transport Chain, what role does oxygen play?

Final electron acceptor

41
  1. Although necessary steps in fat metabolism, _______________, _________________, and _________________, DO NOT produce any ATP directly.

lipolysis, Beta-Oxidation, activation

42

For both CHO and FFA, the process of oxidative metabolism begins with _____________.

Krebs Cycle

43

Fat metabolism can generate much more ATP than CHO metabolism because so much more _____________ is formed from___________________.

acetyl-CoA, Beta-oxidation

44

Type I (aka "slow oxidative") muscle fibers have a higher oxidative capacity than Type II muscle fibers because they have more______________.

mitochondria

45

At the end of the Electron Transport Chain what forms when the electrons combine with oxygen with the protons?

Water

46

Why is the NET ATP production from NADH and FADH less than the gross ATP production?

The transport across mitochondrial membrane requires ATP.

47

What is the purpose of the Krebs cycle?

To generate NADH and FADH for the ETC

48
  1. Why is oxidative phosphorylation a more sustainable form of ATP formation than glycolysis?

water is the by product

49
  1. Besides ATP, what are the by-products of oxidative metabolism?

H20 and C02

50

Besides the Acetyl-CoA that forms, how does Beta-Oxidation generate ATP?

By forming NADH and FADH2

51

Why must all fibers progress through the phosphagen system prior to the aerobic system when initially recruited?

AMP stimulates PFK

52

What is the energy released from the electron transport chain directly used for?

to pump protons

53

How does CHO metabolism become inhibited once fat metabolism is activated?

Citrate from the Krebs cycle inhibits PFK

54

What stimulates the ETC to activate?

ADP and Pi levels

55

What role does oxygen play in metabolism?

accepts electrons from third cytochrome of ETC

56

What inhibits glycolysis during high intensity exercise?

Decreasing pH.

57

Energy expenditure estimates made from the measurement of respiratory gases is called_____________________.

Indirect calorimetry

58

Why does the amount of oxygen taken up by the lungs so closely match oxygen usage at the tissue level of the entire body?

The bodies oxygen storage is very limited

59

The amount of oxygen needed to oxidize a molecule of carbohydrate or fat is proportional to the amount of_____________________in that molecule.

Carbon

60

There is a _______________relationship between power output and oxygen consumption.

Linear

61

At your VO2max, oxygen consumption__________ with further increases in the workload.

Plateaus

62

How long does it take for the body to reach Steady-State in response to an aerobic exercise workload?

1-2 mins.

63

An average untrained college-age male would be expected to have a relative VO2max of _______ml/kg/min.

45

64

At low-moderate intensities at a constant workload, oxygen consumption ______________________.

Remains constant

65

What was the proposed estimate that could be made from measuring post-exercise oxygen consumption (EPOC)?

Anaerobic activity

66

In an untrained person the lactate threshold (LT) typically occurs at ________ of their VO2max.

50-60%

67

What does respiratory quotient measure?

Cellular respiration

68

What does RER estimate?

RQ

69

A person consuming 3 Liters of oxygen per minute is using approximately how many kcal of energy?

15

70

What is the principle reason that relative CHO usage increases as exercise intensity increases?

recruitment of progressively glycolytic fibers

71

In order to maximize fat loss, at what intensity should a person exercise during their allotted time for aerobic exercise?

as high as they can safely tolerate and sustain

72

If a 75kg person has a MET max = 20 METs, what is their relative VO2max?

math question

73

At what % of VO2max does the lactate threshold (LT) typically occur in an untrained person?

50-60

74

Why does the LT predict endurance performance better than VO2max does?

LT represents a sustainable workload

75

At constant intensities just above the lactate threshold, what happens to blood lactate levels?

plateaus

76

What component of force plays a significant role in economy?

Elastic

77

Peripheral fatigue refers to fatigue mechanisms that occur within the muscle itself.

True or False

True

78

"Hitting the wall" during a marathon is likely due to which of the following fatigue mechanisms?

glycogen depletion

79

Glycogen depletion and hypoglycemia limit performance in activities lasting less than 60 minutes.

True or false

False

80

How does increased temperature contribute to fatigue?

Increased CHO utilization due to higher EPI levels

81

Nocturnal muscle cramps and EAMC's are both likely caused by what?

Muscle spindle activation and GTO inhibition

82

Steroid and non-steroid hormones can pass through a cell membrane.

True or false

False

83

Which of the following can elicit direct gene activation?

Steroid

84

Which of the following does notincrease glucose availability?

Insulin

85

spite the reliance on CHO metabolism and increasing Glucose levels in the blood, ____________ levels decrease as exercise continues.

Insulin

86

Which two hormones are collectively referred to as catecholamines?

Epinepherine and Norepinepherine

87

At what exercise intensity are Epinepherine and Norepinepherine released?

60-70% VO2max

88

Which hormone stimulates both liver glycogenolysis and gluconeogenesis?

Glucagon

89

A limiting factor in continued blood glucose homeostasis while competing in a prolonged endurance event is the muscle glycogen supply.

True or False

False

90

Throughout prolonged endurance events lasting several hours, cortisol stimulates lipolysis to ensure adequate FFA concentration.

True or False

False

91

Which hormone stimulates proteolysis in muscle and frees amino acids for gluconeogenesis?

Cortisol

92

During a 10 second all out sprinting effort, which of the following is the most likely cause of fatigue?

Accumulation of inorganic phosphate

93

During a prolonged endurance event such as marathon, which of the following is the most likely cause of a fatigue?

glycogen depletion

94

Which of the followingDOES NOT contribute to hydrogen ion (H+) accumulation during high intensity exercise?

aerobic metabolism of glucose

95

How does heat contribute to muscle fatigue?

increased rate of CHO utilization

96

Why is blood glucose homeostasis a challenge during exercise?

supply is limited and glucose uptake by muscle doubles

97

What stimulates most of the feed forward glucose control during exercise?

EPI activation of liver Glycogenolysis

98

What is the contraction related activator of GLUT-4 vesicles in skeletal muscle?

Calcium

99

What is the advantage of a separate insulin independent signal for GLUT-4?

Targeted glucose delivery to metabolically active tissue

100

Which hormone plays a permissive role in lipolysis?

Insulin

101

Which hormones stimulate amino acid utilization in prolonged endurance events?

Cortisol and glucagon

102

In order for the muscle to relax, Ca2+ is pumped back into the sarcoplasmic reticulum. This process does not require ATP.

True or False

Needs ATP

103

During the 1rm test, the eccentric contraction is what is being tested.

True or False

Concentric contraction

104

The power stroke is the rate limiting step of the chemo-mechanical coupling step.

True or False

Hydrolysis

105

In this contraction, Myosin cross bridges are formed and recycle, however the filaments do not slide toward each other.

Isometric(static)

106

Three components of muscle fibers:

contractile:Actin and mysoin

series elastic: tendon

parallel elastic: mysium, connectins, s2 subunits

107

contractile:

Actin and mysoin

108

series elastic:

tendon

109

How are motor units recruited?

orderly size principle

110

what are the wto methods to increase force?

rate coding and recruit more muscle fibers

111

length-tension relationship:

optimal length exists for action and myosin interaction to generate active force. passive force increases as muscle length increases

112

force-velocity relationship:

more force generated isometrically than any concentric speed. eccentric contraction have a higher force generating capacities due to passive force

113

ATPase of type 1 unable to hydrolyze ATP as fast.

True or false

true

114

to generate high force, fibers need to shorten slow enough for cross bridging.

true or false

true