MODULE SUPPLEMENT: PULMONARY SYSTEM
Component 1: Pulmonary Ventilation

Mr. Ray, the 72 gentleman you met earlier, has a decreased FEV1, or the amount of air that he can get out forcefully from a full inspiration in 1 second. This is a problem with pulmonary ventilation--the first component in respiration.

The goal of ventilation is to get air from the outside into the alveoli so that gas exchange can occur between the alveoli and the blood. Thus, pulmonary ventilation is simply moving air in and out of our lungs. The air that does get as far as the alveoli is termed Alveolar Ventilation.

The normal relationship of the chest and lungs is such that the lungs keep trying to collapse (elastic recoil) while the chest wall keeps trying to expand. Elastic forces of the lung tissue and the elastic forces created by surface tension are the two main mechanisms involved in the tendency of the lung to recoil.