Type II alveolar cell

Type II alveolar cells (or Type II pneumocytes) are cells in the alveoli of the lungs that produce and secrete surfactant, a substance critical to the respiratory function. They are one of the two types of alveolar cells, the other being Type I alveolar cells, which are involved in the process of gas exchange.

Structure

Type II alveolar cells are cuboidal in shape and occupy approximately 5% of the alveolar surface area. Despite their small surface area, they are more numerous than Type I cells, making up about 60% of the alveolar epithelial cells.

Function

The primary function of Type II alveolar cells is the production and secretion of surfactant. Surfactant is a complex mixture of lipids and proteins that reduces the surface tension of the alveolar fluid, preventing the alveoli from collapsing during exhalation.

In addition to surfactant production, Type II cells are also capable of cellular division and differentiation into Type I alveolar cells. This ability is crucial for the repair and regeneration of the alveolar epithelium following lung injury.

Clinical significance

Deficiencies in surfactant production by Type II alveolar cells can lead to respiratory distress syndrome (RDS), a condition commonly seen in premature infants. In adults, damage to Type II cells can contribute to the development of pulmonary fibrosis, a disease characterized by the thickening and scarring of lung tissue.

See also

• Alveoli
• Type I alveolar cells
• Surfactant
• Respiratory distress syndrome
• Pulmonary fibrosis

References

This Respiratory system related article is a stub. You can help WikiMD by expanding it.