goblet cells
Summary
Goblet cells are specialized columnar epithelial cells found in the respiratory and GI tracts that secrete mucin to form protective mucus. They are a hallmark of mucus-secreting epithelium and undergo hyperplasia in various pathological conditions.
Detail
Goblet cells are unicellular exocrine glands interspersed among absorptive/ciliated epithelial cells in the respiratory tract, small and large intestine, and conjunctiva. They have a characteristic 'goblet' or wine-glass shape due to a large apical mucin-containing vacuole that compresses the nucleus basally. They synthesize and secrete mucins (MUC2 in intestine, MUC5AC/MUC5B in airways) via a merocrine secretion mechanism, forming a protective mucus layer that lubricates surfaces, traps pathogens/particles, and facilitates transit of luminal contents.
Clinical significance: In the GI tract, goblet cell hyperplasia/metaplasia is characteristic of Barrett esophagus, where normal squamous epithelium is replaced by intestinal-type columnar epithelium with goblet cells (intestinal metaplasia), a precursor to esophageal adenocarcinoma - histologic identification of goblet cells is required for diagnosis. In the respiratory tract, goblet cell hyperplasia occurs in chronic bronchitis, asthma, and cystic fibrosis, contributing to excess mucus production and airway obstruction. Goblet cell depletion is seen in ulcerative colitis, correlating with disease activity, and is a distinguishing histologic feature from Crohn disease. Goblet cell carcinoid (goblet cell adenocarcinoma) is a rare, aggressive appendiceal tumor with mixed neuroendocrine and mucinous differentiation, exhibiting more aggressive behavior than typical carcinoid tumors. Loss of goblet cells and mucin production is also relevant in dry eye syndrome (conjunctival goblet cell loss) and in certain malabsorption syndromes.
Sources
- Robbins Basic Pathology, 10th ed.
- Junqueira's Basic Histology, 15th ed.
- First Aid for the USMLE Step 1
- Goljan Rapid Review Pathology
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