Lab 3: Substrate Utilization Flashcards

1
Q

storage form and location for carbohydrates

A

glycogen in the liver and muscle

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2
Q

storage form and location for fats

A

triglycerides in adipose tissue and intramuscular deposits

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3
Q

storage form and location for proteins

A

bodily protein in muscle

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4
Q

major sources of fuel for oxidative ATP production

A

carbs and fats

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5
Q

when is protein used as a fuel source

A

conditions of muscle glycogen depletion (i.e. exhaustive exercise or starvation)

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6
Q

define respiratory exchange rate (RER)

A

ratio of carbon dioxide produced over oxygen consumed (VCO2/VO2)

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7
Q

what technique can be used to calculate RER in the lab

A

indirect calorimetry

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8
Q

how can the RER be used to estimate substrate utilization?

A

fats and carbohydrates use and produce different amounts of O2 and CO2

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9
Q

when RER is known, what else can be calculated?

A

the total energy expenditure (carb + fat)

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10
Q

when total energy expenditure is known, what else can be calculated?

A

absolute amount of energy production from a given substrate

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11
Q

are free fatty acids or glucose oxidized faster?

A

glucose

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12
Q

describe the crossover concept

A

as exercise intensity increases, there is an increase in the contribution of carbohydrates as an energy source

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13
Q

for a trained individual, what happens to the crossover point (on a graph of % VO2 max vs percent energy from fat and carbs)

A

crossover point shifts right

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14
Q

where is the crossover point (50% CHO/ 50% fat) for an untrained individual?

A

30% VO2 max

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15
Q

where is the crossover point (50% CHO/ 50% fat) for a trained individual?

A

40-50% VO2 max

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16
Q

why is the delay in the crossover point advantageous for trained individuals?

A

it helps conserve limited glycogen stores

17
Q

distinguish between absolute and relative contributions of fat and carbohydrate at a given work rate

A

at a low intensity, the relative (%) contribution of fats is higher, but the absolute number of total calories is lower (the absolute amount of fat oxidation is lower (80% of 4 kcals/min = 3.2 kcals/min)

at a moderate intensity, the relative (%) contribution of fats is lower, but the absolute number of total calories is higher (40% of 10 kcals/min = 4 kcals/min)

18
Q

oxygen consumption represents total energy expenditure during what kind of exercise?

A

submaximal, steady state exercise

19
Q

as exercise intensity increases, what happens to VO2 and total energy expenditure

A

increases linearly

20
Q

explain the procedure generally

A

students split 3 groups, three 6 minutes exercise bouts performed on bicycle ergometer or treadmill at three incremental intensities w 5 min break in between; one student in each group performs all three exercise bouts

21
Q

how to determine kp needed to reach a certain power output (watts) at 60 rpm

A

power (watts) = rpm x kp