Which cell type is associated with lamellar bodies that store surfactant in the lungs?

Which cell type is associated with lamellar bodies that store surfactant in the lungs?

• A. Type I pneumocytes
• B. Type II pneumocytes
• C. Alveolar macrophages
• D. Ciliated alveolar epithelium

Answer: (B)

Type II pneumocytes store surfactant in lamellar bodies. These cuboidal cells synthesize phospholipids and surfactant proteins, package them into lamellar bodies, and release them into the alveolar space by exocytosis. The surfactant coats the alveoli, lowering surface tension and preventing collapse during expiration. The other cell types don’t store surfactant: Type I pneumocytes are thin cells specialized for gas exchange and lack lamellar bodies; alveolar macrophages reside in the airspaces and help clear debris; and there is no ciliated alveolar epithelium.

Type II pneumocytes store surfactant in lamellar bodies. These cuboidal cells synthesize phospholipids and surfactant proteins, package them into lamellar bodies, and release them into the alveolar space by exocytosis. The surfactant coats the alveoli, lowering surface tension and preventing collapse during expiration. The other cell types don’t store surfactant: Type I pneumocytes are thin cells specialized for gas exchange and lack lamellar bodies; alveolar macrophages reside in the airspaces and help clear debris; and there is no ciliated alveolar epithelium.