The Probert Encyclopaedia of Medicine

BRONCHIOLES

The bronchioles are the intermediate air passages within the lungs. They branch off of the large bronchi and extend to the smaller branches of the alveolar ducts. Each respiratory bronchiole subdivides into five or more alveolar ducts. The structure of the bronchi, bronchioles, alveolar ducts, and alveoli is often called the ' pulmonary tree' because its extensive branching resembles the limbs and leaves of a tall deciduous tree.
Research Bronchioles