Which alveolar cell type is primarily responsible for surfactant production?

Which alveolar cell type is primarily responsible for surfactant production?

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

Answer: (D)

Surfactant production is carried out by alveolar type II pneumocytes. These cuboidal cells line the alveoli and contain lamellar bodies packed with phospholipids and surfactant proteins. When released, surfactant coats the alveolar surface, lowering surface tension to prevent collapse during exhalation. Type II cells also act as progenitors that can differentiate into Type I cells to repair the alveolar epithelium after injury. By contrast, Type I pneumocytes form the thin gas-exchange barrier and do not produce surfactant, alveolar macrophages are immune cells in the airspaces, and Clara cells reside in bronchioles, secretory cells not involved in alveolar surfactant production.

Surfactant production is carried out by alveolar type II pneumocytes. These cuboidal cells line the alveoli and contain lamellar bodies packed with phospholipids and surfactant proteins. When released, surfactant coats the alveolar surface, lowering surface tension to prevent collapse during exhalation. Type II cells also act as progenitors that can differentiate into Type I cells to repair the alveolar epithelium after injury. By contrast, Type I pneumocytes form the thin gas-exchange barrier and do not produce surfactant, alveolar macrophages are immune cells in the airspaces, and Clara cells reside in bronchioles, secretory cells not involved in alveolar surfactant production.