Where does air (and not food) pass during respiration?

During respiration, air passes through the nasopharynx, which is the upper part of the pharynx located behind the nose. The nasopharynx serves as a passageway for air from the nasal cavity to the oropharynx and then to the larynx and trachea, ultimately leading to the lungs. It is lined with mucous membrane and is involved in the warming and humidifying of inhaled air, as well as aiding in the immune response due to its association with the adenoids, which help trap pathogens.

In contrast, the esophagus is primarily a muscular tube that carries food from the mouth to the stomach and does not serve any function in respiration, while the oropharynx is a passage that allows both air and food to pass, but is primarily associated with the act of swallowing food rather than the respiratory process. The nasopharynx is specifically dedicated to the passage of air and plays a vital role in normal respiration.