Which cell type is the principal source of alveolar epithelium regeneration after injury?

Which cell type is the principal source of alveolar epithelium regeneration after injury?

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

Answer: (B)

The principal source of alveolar epithelium regeneration after injury is Type II pneumocytes. These cells act as the resident progenitor cells in the alveoli, proliferating in response to injury and then differentiating into Type I pneumocytes to re-create the thin, gas-exchanging lining. Type I pneumocytes themselves are specialized for gas exchange and do not proliferate to repair damaged areas; they are ultimately derived from Type II cells during the repair process. Alveolar macrophages are immune cells that clear debris and coordinate responses, not rebuild the epithelium, and goblet cells secrete mucus in the conducting airways rather than in the alveolar walls.

The principal source of alveolar epithelium regeneration after injury is Type II pneumocytes. These cells act as the resident progenitor cells in the alveoli, proliferating in response to injury and then differentiating into Type I pneumocytes to re-create the thin, gas-exchanging lining. Type I pneumocytes themselves are specialized for gas exchange and do not proliferate to repair damaged areas; they are ultimately derived from Type II cells during the repair process. Alveolar macrophages are immune cells that clear debris and coordinate responses, not rebuild the epithelium, and goblet cells secrete mucus in the conducting airways rather than in the alveolar walls.