Library · Physiology
Pulmonary ventilation
Make it clearer
Pulmonary ventilation is the movement of air in and out of the alveoli, the little sacs where the respiratory tree ends. There, between alveolar air and the blood in the pulmonary capillaries, the smallest vessels in the lung, gases are exchanged: oxygen goes in and carbon dioxide comes out.
The path has two parts with different jobs. The conducting zone is made up of most of the bronchioles and the large airways, and its only job is to carry air to where exchange takes place. The respiratory zone is the destination, and it is made up of the respiratory bronchioles, the alveolar ducts, the alveolar sacs and the alveoli. The large tubes only distribute the air; the exchange happens at the end.
And the lung does not ventilate the same way everywhere. At the base, 50% more air comes in than at the apex, the top of the lung. When ventilation and perfusion, which is blood flow, stop matching up well, that can contribute to hypoxemia, which means too little oxygen in the blood.
In brief
Pulmonary ventilation is the flow of air in and out of the alveoli, where gases are exchanged with capillary blood.
Most bronchioles and large airways make up the conducting zone, which delivers air to the alveoli; the respiratory zone comprises respiratory bronchioles, alveolar ducts and alveolar sacs.
The large tubes only distribute the air; the exchange happens at the end.
The lung does not ventilate evenly: the base receives 50% more than the apex, and mismatch with perfusion can contribute to hypoxemia.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingPhysiology, Pulmonary Ventilation and Perfusion, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated