KEY TAKEAWAYS •
The upper airway involves the nose, pharynx, and larynx.
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There is a conducting zone and a respiratory zone in the airways. The conducting zone conducts air and the respiratory zone exchanges gases.
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There are three major alveolar cells: type I cells, type II cells, and alveolar macrophages.
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A bronchopulmonary segment has its own terminal bronchiole and its own arterial supply.
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The respiratory centers are contained with the medulla and the pons.
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There are several gas laws that determine the way gases behave in the body.
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Oxygen is mainly carried on hemoglobin, while carbon dioxide is carried as bicarbonate, dissolved CO2, and as carbaminohemoglobin.
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There are multiple lines of defense against pathogens and debris that get into the airways or alveoli.
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The pulmonary circuit starts at the pulmonary trunk and ends at four pulmonary veins.
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