bronchial

Bronchial refers to anything relating to the bronchi, the air-conducting passages of the lungs. The term is used to describe structures, tissues, or processes associated with the bronchial tree, which begins at the bifurcation of the trachea into the right and left main bronchi and extends through progressively smaller airways: lobar (secondary) bronchi, segmental (tertiary) bronchi, bronchioles, and terminal bronchioles.

Anatomically, the walls of larger bronchi contain cartilage plates and a layer of smooth muscle. Smaller bronchi have less cartilage and more smooth muscle. The mucosal lining is pseudostratified ciliated columnar epithelium with goblet cells, which produce mucus. The bronchial circulation includes bronchial arteries that supply the airway walls, distinct from the pulmonary arteries involved in gas exchange. Innervation is autonomic: sympathetic fibers promote bronchodilation, while parasympathetic fibers promote bronchoconstriction.

Clinically, bronchial involvement is central to many respiratory conditions. Bronchitis denotes inflammation of the bronchi; chronic bronchitis is a component of chronic obstructive pulmonary disease. Asthma is characterized by bronchial hyperresponsiveness and reversible airway obstruction, often treated with bronchodilators and anti-inflammatory agents. Bronchoscopy is a procedure used to visualize the bronchial tree and obtain samples. Diagnostic imaging and pulmonary function testing can reveal bronchial thickening, mucus plugging, patterns consistent with asthma, or bronchiectasis.

Etymology: the term derives from Greek bronchía for windpipe, and is used in contrast to terms describing the alveoli or pulmonary vessels.