Légutak

Légutak are the airways that transport air between the external environment and the lungs. They include the upper airways, such as the nasal cavities, paranasal sinuses, and pharynx, and the lower airways, which comprise the larynx, trachea, bronchi, bronchioles, and the alveolar region where gas exchange occurs. The primary functions of the légutak are to conduct air to the lungs while conditioning it—cooling and warming, humidifying, and filtering out particles—and to protect the lower airways from injury and infection. The mucociliary apparatus, consisting of mucus production and ciliary movement, helps clear debris and pathogens from the passages.

Respiratory physiology involves ventilation—moving air in and out of the lungs—and the regulation of airway caliber. Breathing is controlled by the brainstem respiratory centers and chemical sensors that monitor carbon dioxide, oxygen, and pH levels. Airway resistance is modulated by smooth muscle tone in the bronchi and bronchioles, and can vary during physiological states or in disease, such as bronchoconstriction in asthma.

Clinical relevance: Diseases affecting the légutak range from upper airway conditions like rhinitis and sinusitis to lower airway diseases such as asthma, chronic obstructive pulmonary disease (COPD), bronchitis, and bronchiolitis. Infections, tobacco smoke, environmental exposures, and allergies can impair airway function. Diagnosis commonly uses spirometry to assess airflow, imaging to view structural changes, and endoscopic techniques for direct examination of the airways. Treatments aim to reduce inflammation, relieve obstruction, treat infections, and improve airway patency.

Development and variation: The légutak develop through fetal life and continue to adapt with age. There are anatomical and functional variations among individuals and species that influence ventilation efficiency and disease susceptibility.