What structures are primarily involved in the upper airway?

• A. Lungs and pleura
• B. Nasal cavity, oropharynx, and larynx
• C. Nasal cavity, nasopharynx, oropharynx, and laryngopharynx
• D. Alveoli and bronchioles

Answer: (C)

The upper airway consists of several key structures that play a crucial role in transporting air and facilitating processes such as filtering, humidifying, and warming the inspired air before it reaches the lungs. The primary structures involved in the upper airway include the nasal cavity, nasopharynx, oropharynx, and laryngopharynx.

The nasal cavity is the entry point for air, where it is filtered by nasal hairs and warmed and humidified by the mucous membranes. Following the nasal cavity, air passes through the nasopharynx, which serves as a passageway that connects the nasal cavity to the oropharynx. The oropharynx is involved in both respiratory and digestive functions, as it is the part of the pharynx that is also shared with food during swallowing. Lastly, the laryngopharynx serves as the region where air and food diverge, leading to either the trachea for respiration or the esophagus for digestion.

In contrast, the other options refer to structures that are primarily involved in the lower airway and gas exchange, such as the lungs, pleura, alveoli, and bronchioles, which are essential for respiration but do not fall under the definition of upper airway structures. Understanding