Villi (singular: villus) are tiny, finger-like structures that protrude from the wall of the intestine and have additional cell membrane extensions called microvilli (singular: microvillus). In humans, the villi and microvilli together increase intestinal absorptive surface area 30-fold and 600-fold, respectively, providing exceptionally efficient absorption of nutrients in the lumen. There are also enzymes on the surface for digestion. Villus capillaries collect amino acids and simple sugars taken up by the villi into the blood stream. Villus lacteals collect absorbed fatty acids.