Alveolar septum

Alveolar septum is a thin wall or partition in the alveoli of the lungs, separating adjacent alveoli. It is a crucial component of the respiratory system, playing a vital role in the process of gas exchange.

Structure

The alveolar septum is composed of a thin layer of connective tissue and capillaries. The connective tissue provides structural support, while the capillaries facilitate the exchange of gases. The septum is lined with alveolar epithelial cells, which are of two types: Type I and Type II. Type I alveolar cells are flat and thin, allowing for efficient gas exchange, while Type II alveolar cells secrete surfactant, a substance that reduces surface tension and prevents the alveoli from collapsing.

Function

The primary function of the alveolar septum is to facilitate gas exchange. Oxygen from the inhaled air diffuses across the thin walls of the septum and into the capillaries, where it binds to hemoglobin in red blood cells. Simultaneously, carbon dioxide, a waste product of cellular metabolism, diffuses from the blood into the alveoli, from where it is exhaled.

Clinical significance

Damage to the alveolar septum can lead to various respiratory disorders. For instance, in pulmonary fibrosis, the septum becomes thickened due to the accumulation of excess fibrous connective tissue, impairing gas exchange. In emphysema, the walls of the alveoli are destroyed, leading to the formation of large air spaces that reduce the surface area available for gas exchange.

See also

• Alveoli
• Respiratory system
• Pulmonary fibrosis
• Emphysema