The nasopharynx is the upper part of the pharynx located behind the nose and above the soft palate. It serves as a passageway for air from the nasal cavity to the oropharynx and plays a crucial role in respiratory function. Additionally, it houses the adenoids, which are part of the immune system, helping to trap pathogens and prevent infections. The nasopharynx also aids in equalizing pressure in the middle ear through the Eustachian tubes.