The respiratory bronchioles and the alveolar ducts are responsible for 10% of the gas exchange.

The receptors are less abundant in the distal airways, and absent beyond the respiratory bronchioles.

They travel with and branch with the bronchi, ending about at the level of the respiratory bronchioles.

In human anatomy, respiratory bronchioles exists proximal to the alveolar ducts.

Alveolar ducts are distal continuations of the respiratory bronchioles.

The respiratory bronchioles are the narrowest airways of the lungs, one fiftieth of an inch across.

Latter divisions including the respiratory bronchiole, alveolar ducts and alveoli, are specialized for gas exchange.

Each of the terminal bronchioles divides to form respiratory bronchioles which contain a small number of alveoli.

The respiratory bronchioles represent the transition from the conducting portion to the respiratory portion of the respiratory system.

Centriacinar (or centrilobular) emphysema: The respiratory bronchiole (proximal and central part of the acinus) has expanded.

Terminal bronchioles in turn divide into respiratory bronchioles which divide into alveolar ducts.

These structures occur most frequently around the initial site of coal dust accumulation - the upper regions of the lungs around respiratory bronchioles.

The respiratory bronchioles in the lungs terminate in acini, many-lobed sacs containing groupings of alveoli.

Panacinar (or panlobular) emphysema: The entire respiratory lobule, from respiratory bronchiole to alveoli, has expanded.

Mineral dust airway disease is due to inhaled mineral dust causing fibrosis and narrowing of primarily the respiratory bronchioles.

The lung parenchyma is strictly used to refer solely to alveolar tissue with respiratory bronchioles, alveolar ducts and terminal bronchioles.

The term diffuse signifies that lesions appear throughout both lungs, while panbronchiolitis refers to inflammation found in all layers of the respiratory bronchioles (those involved in gas exchange).

Alveolar ducts are tiny ducts that connect the respiratory bronchioles to alveolar sacs, each of which contain a bunch of alveoli (the balls).

The conducting zone contains the trachea, the bronchi, the bronchioles, and the terminal bronchioles The respiratory zone contains the respiratory bronchioles, the alveolar ducts, and the alveoli.

Terminal bronchioles mark the end of the conducting division of air flow in the respiratory system while respiratory bronchioles are the beginning of the respiratory division where actual gas exchange takes place.

The diagnostic criteria include severe inflammation in all layers of the respiratory bronchioles and lung tissue lesions that appear as nodules within the terminal and respiratory bronchioles in both lungs.

The segmental bronchi divide into many primary bronchioles which divide into terminal bronchioles, each of which then gives rise to several respiratory bronchioles, which go on to divide into two to 11 alveolar ducts.

DPB is distinguished by the presence of lesions that appear on X-rays as nodules in the bronchioles of both lungs; inflammation in all tissue layers of the respiratory bronchioles; and its higher prevalence among individuals with East Asian lineage.

In DPB, the nodules are more restricted to the respiratory bronchioles, while in OB they are often found in the membranous bronchioles (the initial non-cartilaginous section of the bronchiole, that divides from the tertiary bronchus) up to the secondary bronchus.