Small intestine lining. Light micrograph of a section through the lining (mucosa) of the ileum, part of the small intestine, showing the numerous crypts of Lieberkuhn (purple/white). The crypts are seen in both transverse section (upper left to bottom right) and in longitudinal section (rest of frame). They lie between the intestinal villi (finger-like projections of the lining, not seen), producing new cells which mature and replace dead cells lost into the lumen (cavity) of the intestine. The crypts are composed of columnar enterocyte cells (purple) and mucus-secreting goblet cells (light blue). Trichrome blue stain. Magnification unknown.