The pH of the lungs and stomach varies significantly due to their different physiological functions and environments.
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Stomach: The pH of the stomach is typically very acidic, ranging from about 1.5 to 3.5. This low pH is primarily due to the secretion of gastric acid, mainly hydrochloric acid (HCl), which helps in digestion and protects against pathogens.
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Lungs: The pH in the lungs, particularly in the alveolar spaces and the blood that circulates through them, is more neutral to slightly alkaline, generally around 7.35 to 7.45. This range is crucial for proper gas exchange (oxygen and carbon dioxide) and maintaining normal physiological functions. The lungs play a role in regulating blood pH through the exhalation of carbon dioxide, which can affect the acidity of the blood.
In summary, the stomach has a low pH (acidic) due to digestive processes, while the lungs maintain a more neutral to slightly alkaline pH to support respiratory functions.