Gosset Molecular Classification
Other
Other Names
Alveoli (plural), Pulmonary alveolus, Air sac
Disease Roles
Alveolus Overview
The alveolus is the microscopic air sac at the end of each bronchiole in the lungs. It serves as the primary site of gas exchange between inhaled air and blood. Each alveolus has extremely thin walls composed mainly of type I pneumocytes that facilitate rapid diffusion of oxygen into blood and removal of carbon dioxide from it. Type II pneumocytes produce pulmonary surfactant, which reduces surface tension and prevents collapse during exhalation. Alveolar macrophages patrol these spaces, removing debris and pathogens. Diseases affecting the structure or function of alveoli can severely impair breathing efficiency.
Mechanism of Action
Biological Functions
Gas exchange (oxygen and carbon dioxide transfer)
Surfactant production (by type II pneumocytes)
Immune defense (via alveolar macrophages)
Disease Associations
Pneumonia
Emphysema
Tuberculosis
Acute respiratory distress syndrome (ARDS)
Pulmonary edema
Safety Considerations
- Susceptibility to collapse if surfactant is deficient
- Vulnerability to infection and inflammation
- Overdistention risk with mechanical ventilation