Small intestine. Light micrograph of a cross section through the villi of the human small intestine. The small intestine runs from the stomach to the large intestine. It is where digestion is completed and nutrients are absorbed into the blood. Villi are finger-like projections that increase the surface area available for nutrient absorption. Alcian blue and PAS-D (periodic acid-schiff diastase) stain. Magnification: x285 when printed 10 centimetres wide.