Respiratory tract

The respiratory tract, also known as the airway or bronchial tree in some contexts, is an anatomical subdivision of the human body responsible for conducting air from outside into the lungs where gas exchange occurs. It consists of two main parts: - The upper respiratory tract, including nasal cavity, sinuses, pharynx, and larynx. - The lower respiratory tract, comprising trachea, bronchi, bronchioles, and alveoli. Its primary functions include transporting oxygen to alveoli for gas exchange with blood and removing carbon dioxide from circulation. The lining contains specialized epithelial cells—such as ciliated cells and goblet cells—that trap debris and pathogens in mucus which is then cleared by ciliary action. Immune defense is provided by resident macrophages and lymphocytes that respond to inhaled threats. While many drugs target specific proteins or cell types within this system (such as β2 adrenergic receptors in asthma), "respiratory tract" itself does not refer to a discrete therapeutic target but rather an organ system composed of multiple tissues performing integrated physiological roles.

Other names

AirwayAirwaysRespiratory passagesBronchial tree (context-dependent)