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38 Cards in this Set
- Front
- Back
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Homeostasis |
A steady and an unchanging internal environment |
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At rest, almost 100% of the energy required to sustain bodily functions is produced by what SYSTEM? |
Aerobic |
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Rest-to-exercise transitions |
Anaerobic energy sources contribute to the overall production of ATP at the beginning of exercise. During a 3 minute bout of exercise the PC concentration in muscle falls greatly |
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Does glycolysis contribute to ATP production in the first minutes of exercise? |
Yes. ATP levels remain unchanged. |
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Oxygen deficit |
Lag in oxygen uptake in the first few minutes of exercise and an equal time period after steady state has been obtaibed. |
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Recovery from exercise |
magnitude and duration of exercise of the elevated metabolic rate are influenced by the intensity of the exercise |
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Oxygen debt |
The elevated oxygen uptake [ above resting levels] following exercises |
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The two portions of oxygen debt [ EPOC]: |
Rapid portion--immediaty following exercise
Slow portion -- persist 30 minutes after exercise |
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Rapid portion of oxygen debt: |
Restores oxygen that was required to resynthesize stored ATP and related tissue stores of o2[ -20% of the of the o2 debt] |
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Reasons EPOC is greater during high intensity exercise: |
Heat production and body temperature are higher
PC is depleted and more o2 is required for its resynthesis
Higher blood lactate levels means more o2 is required for lactate conversion to glucose in GLUCONEOGENESIS
Hormones levels are much higher |
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Short term intense exercise |
ATP-PC system supplies all the needed ATP for exercise lasting 1 to 5 seconds After 5 seconds, glycolysis begins to make ATP |
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Prolonged exercise |
Energy for this, comes from aerobic metabolism |
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Incremental exercise tests |
Usually conducted on a treadmill or a cycle ergometer |
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Maximal oxygen uptake |
The maximal capacity to transport and utilize oxygen during exercise When VO2 max is reached, increase in power doesn't result in an increase in oxygen uptake |
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Onset of blood lactate accumulation |
Oxygen consumption at which a specific blood lactate concentration is reached |
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Possible mechanisms to explain the lactate threshold during incremental exercise |
Low muscle oxygen Accelerated glycolysis due to epinephrine Recruitment of fast-twitch fibers Reduced rate of lactate removal |
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Respiratory exchange ratio |
Ratio of the volume of carbon dioxide [ VCO2] produced to the volume of oxygen consumed[ O2] |
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How can the R be used to estimate whether fat or carbohydrate is being used as a fuel? |
The subject must reach a steady state |
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Crossover point |
A progressive shift occurring from fat to carbohydrate metabolusm |
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Which muscle fibers are best for the shift from fat to carbohydrate metabolism? |
Fast-twitch fibers. They have more glycolytic enzymes |
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High levels of hormones increase phoshorylase activity? T/f |
True |
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Why do low muscle glycogen levels produce fatigue? |
Depletion of available carbohydrates reduces the rate of glycolysis, reducing the number of pyruvate in the muscle. Fat metabolism is also reduced because of low levels of krebs-cycle intermediates |
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Increased glycogen usage during high intensity occurs due to: |
Fast twitch fibers and increased hormone levels |
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During prolonged exercise, much of the carbohydrate metabolized comes from muscle glycogen, when the levels decline, what happens? |
Blood glucose becomes an increasingly important source of fuel |
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Which fat stores are used as a fuel source varies as a function of the exercise intensity and duration |
Plasma fatty acids are primary during low- intensity exercise
Higher work rates increase metabolism of muscle Triglycerides
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Lactate as a fuel source |
Lactate removed from the blood can be converted to pyruvate, which can then be transformed to acetyl-CoA |
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In the context of prolonged exercise, a steady state oxygen uptake can generally be maintained during submaximal, --------- ---------- exercise |
Moderate- intensity |
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Anaerobic threshold |
A common term used to describe the point of a systematic rise in blood lactate during incremental exercise. |
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Maximal oxygen uptake |
The maximal capacity to transport and utilize oxygen during exercise |
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The energy to perform a short term exercise of high intensity is produced primarily from |
Anaerobic metabolic pathways |
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Onset of blood lactate |
The exercise intensity or oxygen consumption at which a specific blood lactate concentration is reached |
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A NONINVASIVE TECHNIQUE used to estimate the percent contribution of carbohydrate or fat to energy metabolism during an exercise is the |
Respiratory exchange ratio |
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During prolonged exercise of more than two hours, the muscle and liver stores of ---‐ can reach very low levels |
Glycogen |
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--‐--glycogen stores mainly serve as a means of replacing blood glucose levels |
Liver |
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Which of the following energy sources play a greater role during low intensity exercise? |
Blood glucose |
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Enzymes capable of degrading muscle proteins called ---- are activated |
Proteases |
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A factor that influences Vo2 max depends on the muscles ability |
Take up oxygen and produce ATP areobically |
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Respiratory quotient ratio |
A non-invasive technique used to estimate the percent contribution of Carbohydrate or fat energy metabolism
* ratiomof carbon dioxide output to the volume of oxygen consumed |
