Organ System Respiratory system Question #10044
Single Choice Easy

Q How does the partial pressure of oxygen and carbon dioxide compare in atmospheric air versus alveolar air?

ID: #10044 Respiratory system 145 views
Question Info
#10044Q ID
EasyDifficulty
Respiratory systemTopic

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  • A Partial pressure of oxygen lesser, partial pressure of carbon dioxide higher
  • B Partial pressure of oxygen higher, partial pressure of carbon dioxide lesser
  • C Partial pressure of oxygen lesser, partial pressure of carbon dioxide lesser
  • D Partial pressure of oxygen higher, partial pressure of carbon dioxide higher
Correct Answer

Explanation

The partial pressure of oxygen in atmospheric air is higher (159 mm Hg) compared to that in alveolar air (104 mm Hg). On the other hand, the partial pressure of carbon dioxide is lower (0.3 mm Hg) in atmospheric air compared to that in alveolar air (40 mm Hg). This difference in partial pressures of oxygen and carbon dioxide is due to the exchange of gases between alveoli and capillaries during respiration. Oxygen diffuses from alveoli into capillaries while carbon dioxide diffuses from capillaries into alveoli, leading to a decrease in partial pressure of oxygen and an increase in partial pressure of carbon dioxide in alveolar air.

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