Confocal image of villi from the human small intestine. The finger-like shape increases the surface area of the intestine, improving the efficiency of food absorption. The intestinal crypts (enzyme secreting glands) can be seen below the villi. The green stain highlights the nucleoli of the rapidly growing epithelial layer of both the villi and the crypts. All the nuclei are stained red and the epithelial cell membranes appear blue.