Villi from the small intestine

Cryosection of human small intestinal mucosa, showing the villi. These are finger-like projections which increase the surface area of the intestine, improving the efficiency of food absorption. Integrin which can be found on the basolateral membrane of epithelial cells, and also shows up on scattered stromal cells, is stained in green. Cytokeratin, which stains epithelial cells, is in blue, and cell nuclei are stained in red.