Intestinal cells. Light micrograph of a section through two folds (villi) in the small intestine. The villi are aligned vertically, with one at left and one at right. Each fold consists of an inner layer of supportive connective tissue (irregular structure), overlaid by an outer layer of columnar epithelial cells). The round structures are the nuclei of these cells. The folded nature of the villi increases the surface area for absorption of nutrients by the microvilli (not clearly seen) on the outer surface of the epithelial cells.