Darmepithel

Darmepithel refers to the specialized epithelium lining the lumen of the gastrointestinal tract. It comprises a single layer of cells that forms the first barrier between luminal contents and the underlying tissue. It is most developed in the small intestine and colon, where it undertakes digestion, absorption, and immune defense.

Cellular composition includes enterocytes with microvilli for nutrient absorption; goblet cells that secrete mucus; enteroendocrine cells that release gut hormones; Paneth cells in the crypts producing antimicrobial peptides such as defensins; M cells over Peyer's patches that sample antigens; and tuft cells with chemosensory functions.

Histologically, the small-intestinal epithelium forms finger-like villi and tubular crypts; the colon has crypts but lacks villi. Enterocytes’ brush border carries digestive enzymes. Tight junctions between adjacent cells regulate paracellular permeability. The epithelium rests on a lamina propria with blood vessels and lymphatics that support nutrient transport and immune surveillance.

Turnover is rapid: stem cells at the crypt base (Lgr5+) continuously proliferate and differentiate into the major lineages, then migrate up the villus and are shed at the tip approximately every 3–5 days.

Functions include nutrient and water absorption, electrolyte balance, and maintenance of a selective barrier against pathogens. The mucus layer and antimicrobial peptides help control microbes, while interactions with the gut-associated immune system contribute to immune homeostasis. Disruption of the Darmepithel is involved in conditions such as celiac disease and inflammatory bowel disease.