Small intestine lining. Coloured scanning electron micrograph (SEM) of numerous microvilli (tiny projections) on the inner surface of the small intestine. Microvilli are folds on the surface of a cell that increase the cell's surface area. This allows the cell to absorb more nutrients from the food that passes over it. The small intestine is the part of the intestinal tract where most of the nutrients are absorbed. After travelling through the small intestine, digested food passes to the large intestine, where most of the water is absorbed. Magnification: x8500 when printed 10cm wide.