The small intestine is a long, coiled tube that funnels digested food from the stomach into the colon (the large intestine). Along the way, the digested material is further broken down and nutrients and amino acids are absorbed.
The material first enters the duodenum, one of three sections of the small intestine where digestion is aided by enzymes secreted by the pancreas and bile from the liver. The middle section, the jejunum, propels the food into the ileum, the final and longest section food travels through before being emptied into the colon. Absorption of vitamins, proteins, carbohydrates and nucleic acids happens as the food moves through the jejunum and ileum.