Which alveolar cell type is responsible for surfactant production?

Which alveolar cell type is responsible for surfactant production?

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

Answer: (A)

Surfactant production comes from alveolar type II pneumocytes. These cuboidal epithelial cells contain lamellar bodies that store and release surfactant, a phospholipid-rich mixture (notably DPPC) with surfactant proteins that reduce surface tension at the air–liquid interface in the alveoli. This reduction prevents alveolar collapse during exhalation and improves lung compliance. Type II cells also act as progenitors to regenerate Type I pneumocytes after injury. In contrast, Type I pneumocytes are the thin cells forming the gas-exchange barrier, alveolar macrophages handle immune debris, and endothelial cells line the capillaries.

Surfactant production comes from alveolar type II pneumocytes. These cuboidal epithelial cells contain lamellar bodies that store and release surfactant, a phospholipid-rich mixture (notably DPPC) with surfactant proteins that reduce surface tension at the air–liquid interface in the alveoli. This reduction prevents alveolar collapse during exhalation and improves lung compliance. Type II cells also act as progenitors to regenerate Type I pneumocytes after injury. In contrast, Type I pneumocytes are the thin cells forming the gas-exchange barrier, alveolar macrophages handle immune debris, and endothelial cells line the capillaries.