bronchiole

One of approximately six generations of increasingly finer subdivisions of the bronchi, all less than 1 mm in diameter, and having no cartilage in its wall, but relatively abundant smooth muscle and elastic fibers. SYN: bronchiolus [TA].

- respiratory bronchioles the smallest bronchioles (0.5 mm in diameter) that connect the terminal bronchioles to alveolar ducts; alveoli rise from part of the wall. SYN: bronchioli respiratorii.

- terminal b. the end of the nonrespiratory conducting airway; the lining is simple columnar or cuboidal epithelium without mucous goblet cells; most of the cells are ciliated, but a few nonciliated serous secreting cells occur. SYN: bronchiolus terminalis.

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bron·chi·ole 'bräŋ-kē-.ōl n a minute thin-walled branch of a bronchus

bron·chi·o·lar .bräŋ-kē-'ō-lər adj

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n.

a subdivision of the bronchial tree that does not contain cartilage or mucous glands in its wall. Bronchioles open from the fifth or sixth generation of bronchi and extend for up to 20 more generations before reaching the terminal bronchioles. Each terminal bronchiole divides into a number of respiratory bronchioles, from which the alveolus open. Each terminal bronchiole conducts air to an acinus in the lung.

• bronchiolar adj.

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bron·chi·ole (brongґke-ōl) a subdivision of the branched bronchial tree 1 mm or less in diameter, differing from the bronchi in having cuboidal epithelial cells and lacking cartilage plates. Each bronchiole subdivides into several smaller terminal bronchioles. In official terminology, called bronchiolus.

Bronchiole and subdivisions.