Which cell type secretes mucus in respiratory and intestinal epithelia?

• A. Goblet cell
• B. Basal cell
• C. Type II pneumocyte
• D. Alveolar macrophage

Answer: (A)

Goblet cells are mucus-secreting cells embedded in the lining of the respiratory and intestinal epithelia. They produce mucins that hydrate to form mucus, creating a protective, lubricating layer. In the airways, mucus traps inhaled particles and microbes, and ciliated cells help move the mucus out of the tract. In the gut, mucus coats the lining to protect it from digestion and mechanical stress and to ease the passage of contents. Other cell types have different roles: basal cells act as progenitors to renew the epithelium, Type II pneumocytes secrete surfactant to reduce surface tension in the alveoli, and alveolar macrophages perform phagocytosis of debris and pathogens. Thus, goblet cells are the mucus-secreting cells in these epithelia.