The small intestine is a long narrow tube that helps the food composition along with other compounds by reacting with water in the small intestine with the help of the liver and pancreas. There are a number of tiny projections called villi that absorb the products and end digestion. The small intestine has a surface ten times greater than the skin. It is about 20-25 feet long where the large intestine which is wider in diameter is only 5 feet long. Together the small and large intestine is about 25-30 feet long.