Bronchioles in the Lungs: Structure, Function & Count

The lungs are made up of millions of tiny air sacs called alveoli. These alveoli are clustered together in groups of about 100, and these clusters are called lobules. Each lobule is supplied by a single bronchiole, which is a small airway that branches off from a larger airway called a bronchus. The bronchi themselves branch off from the trachea, which is the main airway that connects the lungs to the windpipe.

The total number of bronchioles in the lungs is not precisely known, but it is estimated to be in the range of 20 to 30 million. Each bronchiole is only about 1 to 2 millimeters in diameter, but they play a vital role in the respiratory system by allowing air to flow in and out of the alveoli.