Normal intestinal mucosa. Biopsy of the second portion of the duodenum of an 8-year-old US child showing normal histology of the intestinal mucosa. Long, finger-like villi and relatively shallow crypts are evident. The villi are populated with columnar epithelial cells (enterocytes) that have brush borders containing enzymes for digestion and absorption; mucus-producing goblet cells are interspersed among the enterocytes. Less than 20 intraepithelial lymphocytes per 100 enterocytes are present. Photomicrograph kindly provided by Steven Czinn, University of Maryland Medical Center.