Question

1- what is the effect of water vapor on the air entering the alveoli?

Answer 1

Answer - Brief Explanation

The composition of air in the atmosphere and in the alveoli differs. In both cases, the relative concentration of gases is nitrogen > O2 > water vapor > CO2. The amount of water vapor present in alveolar air is greater than that in atmospheric air. Recall that the respiratory system works to humidify incoming air, thereby causing the air present in the alveoli to have a greater amount of water vapor than atmospheric air. In addition, alveolar air contains a greater amount of carbon dioxide and less oxygen than atmospheric air. This is no surprise, as gas exchange removes oxygen from and adds carbon dioxide to alveolar air. Both deep and forced breathing cause the alveolar air composition to be changed more rapidly than during quiet breathing. As a result, the partial pressures of oxygen and carbon dioxide change, affecting the diffusion process that moves these materials across the membrane. This will cause oxygen to enter and carbon dioxide to leave the blood more quickly.