Which type of cells are involved in the repair and regeneration of lung epithelium?

• A. Type I pneumocytes
• B. Type II pneumocytes
• C. Goblet cells
• D. Clara cells

Answer: (B)

Type II pneumocytes play a crucial role in the repair and regeneration of lung epithelium primarily because they have the ability to proliferate and differentiate into Type I pneumocytes, which are essential for gas exchange. In the event of lung injury, Type II pneumocytes act as progenitor cells that replace damaged epithelial cells, helping to restore the integrity of the alveolar lining. Additionally, they produce surfactant, which reduces surface tension in the alveoli, preventing collapse during respiration and facilitating effective gas exchange.

Other cell types, such as Type I pneumocytes, are primarily involved in gas exchange and do not possess the same regenerative capabilities. Goblet cells produce mucus and contribute to airway protection but are not directly involved in alveolar epithelial repair. Clara cells, found in the bronchioles, have some role in secreting substances that can protect and regenerate bronchiolar lining; however, they are not specifically responsible for regenerating the alveolar epithelium. Thus, Type II pneumocytes are the key players in the repair and regeneration process of lung epithelium following injury.