Final answer:
The false statement regarding exhalation in a healthy quietly-breathing person is that 'Alveolar pressure goes below atmospheric pressure' during exhalation; actually, alveolar pressure rises above atmospheric pressure to push air out.
Step-by-step explanation:
The question asks which of the following is FALSE regarding exhalation in a healthy quietly-breathing person. The answers include some false and some true statements about the process of exhalation:
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- Some air remains in the respiratory tract at end of exhalation.
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- CO₂ will be displaced from hemoglobin.
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- Alveolar pressure rises above atmospheric pressure.
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- No muscular effort is required to exhale.
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- Alveolar pressure goes below atmospheric pressure.
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- Bicarbonate and H+ will be converted to CO₂ and water.
The false statement regarding exhalation in the options provided is that alveolar pressure goes below atmospheric pressure (e). During exhalation, alveolar pressure rises above atmospheric pressure, causing air to flow out of the lungs. This is because during a gentle exhalation, which is a passive process, the muscles relax and the lung's elasticity creates a positive pressure inside the lungs forcing the air out. All other statements are correct in the context of exhalation:
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- a: Residual volume remains in the respiratory tract even after full exhalation.
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- b: CO₂ is indeed displaced from hemoglobin during exhalation as blood travels through the lungs.
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- c: Alveolar pressure must rise above atmospheric pressure for air to be pushed out of the lungs.
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- d: Normally, exhaling does not require muscular effort because it is primarily a passive process, driven by the recoil of the lungs and relaxation of the diaphragm and intercostal muscles.
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- f: The bicarbonate buffering system does work to convert bicarbonate and hydrogen ions to carbon dioxide and water in the blood, which is then exhaled through the lungs.