Final answer:
The alveoli oxygen partial pressure is different from the ambient oxygen partial pressure due to factors such as the presence of water vapor and carbon dioxide, as well as changes in the alveolar air composition. These differences in partial pressure allow for efficient gas exchange across the alveolar membrane.
Step-by-step explanation:
The alveoli oxygen partial pressure is different from the ambient oxygen partial pressure due to several factors. First, the alveoli contain a greater amount of water vapor and carbon dioxide, and less oxygen, compared to the ambient air. This is because the respiratory system humidifies incoming air and removes oxygen while adding carbon dioxide.
The alveoli oxygen partial pressure is different from the ambient oxygen partial pressure due to factors such as the presence of water vapor and carbon dioxide, as well as changes in the alveolar air composition. These differences in partial pressure allow for efficient gas exchange across the alveolar membrane.
Second, deep and forced breathing cause rapid changes in the alveolar air composition, affecting the partial pressures of oxygen and carbon dioxide. These changes in partial pressure create a pressure gradient that allows for efficient gas exchange across the alveolar membrane.