Library · Anatomy
Bronchiole
Make it clearer
Air that comes in through the nose travels down the trachea and spreads into the bronchi, and the deeper it goes into the lung, the narrower the tube becomes. The bronchioles are those fine tubes at the end: there are twenty to twenty-five generations of branching conducting bronchioles, one after another.
That is where the first big change happens. The bronchi have cartilage in their walls, the firm, flexible material the ear is also made of. Bronchioles no longer do: their walls are held up by smooth muscle, the kind of muscle you do not control at will, and by elastic fibers. The lining inside changes too, to a simple cuboidal epithelium, a single row of cube-shaped cells: club cells appear and goblet cells, the ones that make mucus, disappear.
The last one is called the terminal bronchiole, and it marks where the part of the lung that only carries air ends. After it come the respiratory bronchioles, and that is where the respiratory portion of the lung begins.
In brief
Bronchioles are the fine airways of the bronchial tree: after the segmental bronchi come twenty to twenty-five generations of conducting bronchioles.
Unlike those of the bronchi, their walls have no cartilage and are held up by smooth muscle and elastic fibers; the epithelium becomes simple cuboidal, with club cells and no goblet cells.
The terminal bronchiole ends the conducting zone and opens into the respiratory bronchioles, where the respiratory portion of the lung begins.
Sources (2)
- National Center for Biotechnology Information, StatPearls PublishingAnatomy, Thorax, Bronchial, StatPearlsPublished
- National Center for Biotechnology Information, StatPearls PublishingHistology, Lung, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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