Pathophysiology
Clinical meaning
The upper airway (nasopharynx, oropharynx, larynx) warms, humidifies, and filters inspired air before it reaches the lower airways. Airway patency depends on intact neuromuscular tone, adequate mucociliary clearance, and absence of obstruction. Loss of consciousness, edema, secretions, or foreign bodies can compromise the airway at any level, leading to hypoxemia within minutes.
