luftväg

Luftväg, or the airway, denotes the anatomical passageways that conduct air between the exterior and the gas-exchanging tissues of the lungs. The luftväg comprises the nasal cavity, pharynx, larynx, trachea and bronchi, and the smaller bronchioles down to the alveolar regions. It is commonly divided into upper airways (nose to larynx) and lower airways (trachea to alveoli).

The upper airways condition inspired air by warming, humidifying and filtering it, using mucus membranes, hairs and the mucociliary clearance system. They also participate in voice production and olfaction. The lower airways provide a conduit for air to reach the gas-exchanging surfaces of the lungs, with gas exchange occurring primarily in the alveoli and surrounding capillaries. The mucociliary escalator, along with immune defenses, helps remove inhaled particles and pathogens.

Physiology of the luftväg includes regulation of airway resistance, largely determined by the diameter of conducting airways and governed by autonomic innervation. Bronchodilation is promoted by sympathetic activity and certain circulating mediators, while bronchoconstriction can be driven by parasympathetic activity and inflammatory mediators. The airways also host defense mechanisms, including mucous membranes, secretions, cilia, resident immune cells and alveolar macrophages, which together reduce infection risk and clear debris.

Clinical relevance encompasses a range of conditions affecting patency and function, from upper-airway obstruction and edema to lower-airway diseases such as asthma and chronic obstructive pulmonary disease. Airway management in clinical settings focuses on maintaining patency and adequate ventilation, using strategies such as securing an airway, suction, supplemental oxygen and pharmacologic therapies to modulate tone and inflammation. The term luftväg thus covers both structure and function in respiratory physiology and medicine.