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25 Cards in this Set
- Front
- Back
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What happens to tidal volume (Vt) and breathing frequency when exercise starts?
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They increase proportionally
->Then Vt plateau's |
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What are high ventilatory rates during hard exercise attributed to?
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Incremental increases in frequency
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What happens if breathing f increases?
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Inspiratory and expiratory times decrase during progressice exercise
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Which falls more: expiratory time or inspiratory time?
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Expiratory time
(.:peak expiratory flow rate increases more than peak inspiratory flow rate) |
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What happens to lung compliance at very high volume?
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Lung compliance decreases
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How does minute ventilation (Ve) and metabolic rate (VO2)compare in trained and untrained patients?
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Ve increases linearly with the metabolic rate to ~50-65% of VO2 max
After, Ve increases at a rate disproportionately greater than the change in VO2 |
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What effect does endurance training have on metabolism?
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Delays the ventilatory inflection point
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What is the inflection point?
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Ventilation threshold
(Lac threshold) |
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What is the ventilation/lac threshold?
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Point where lactate in the body is increased but not necessarily linked to ventilation
(increased ventilation doesn't mean increased lactate) |
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What happens past the inflection point?
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Hyperventilation
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By how much can resting values of Ve increase during exercise?
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35 fold (from 5L/min to 190L/min in fit ppl)
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By how much can resting values of cardiac output increase during exercise?
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5-6 times
(from 5L/min to 25-30L/min) |
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Why is ventilation not believed to limit aerobic performance?
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Ve/Q ~= 1 at rest
Ve can increase more than Q during exercise so the Ve/Q ratio increases (even in less fit ppl, the ratio increases similarly, though not to the same extent) |
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How is there a large capacity for gas exchange?
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Alveolar SA= 50m^2
Avg blood volume= 5L 4% of this 5L is in the pulmonary system at any one time during maximal exercise |
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What happens to the pH in the medullary ECF during exercise?
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It increases (pH increase, therefore more alkaline)
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What does this increase in pH mean for the ventilatory response?
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Ventilatory response decreases
.: the role o the central chemoreceptors are important at rest, but not so much during exercise |
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What are the peripheral chemoreceptors sensitive to?
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Mainly chnges in PO2
Also stimulated by increased PCO2 and decreased pH |
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Why can the increase in ventilation during exercise not be attributed to the peripheral chemoreceptors?
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PaO2 is ~ constant in exercise, .: peripheral chemoreceptors aren't stimulated by changes in O2
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What happens to PaCO2 during exercise?
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It DECREASES
.: increase in ventilation can't come from stimulation of peripheral chemoreceptors |
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What happens to arterial pH during exercise? PaO2?
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Arterial pH decreases
(PaO2 fluctuates a bit with arterial pulse waves . .:it's possible that in exercise, these fluctuations in PaO2 increase the sensitivity og the peripheral chemoreceptors t CO2 and H+) |
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What body muscles/receptors were thought to play a role in minute ventilation during exercise?
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Pulmonary mechanoreceptors
Muscle spindle fibers Golgi tendons Skeletal joint receptors |
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What kind of response in minute ventilation is there to the peripheral mechanoreceptors?
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Stimulation of the mechanoreceptors produces an increase in Ve
->this increase is small compared to the large and abrupt increases seen in exercise |
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When does Ve start increasing in the exercise cylce?
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Before exercise begins
->neural control ->similar control at the end of exercise because there's a rapid decrease in Ve |
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What control is responsible for the ventilatory response during exercise?
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Humoral control
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Look at the figures for all sections of respiration
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Look at the figures for all sections of respiration
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