Which cells produce surfactant in the alveoli?

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

Answer: (A)

Surfactant production and secretion in the alveoli are carried out by type II pneumocytes. These cells are specialized for producing and storing surfactant, with surfactant components stored in lamellar bodies and released into the alveolar lining to reduce surface tension. This prevents alveolar collapse during exhalation and helps keep alveoli open for efficient gas exchange.

Type I pneumocytes form the thin, broad surface for gas exchange and do not secrete surfactant. Goblet cells reside in the conducting airways and produce mucus, not surfactant. Alveolar macrophages are immune cells within the alveolar space that clear debris and microbes, not secretory cells for surfactant.