The small intestine is a long, tube-like organ located in the digestive system. It is divided into three sections: the duodenum (8 letters), jejunum (7 letters), and ileum (5 letters). The duodenum is the first section of the small intestine and is responsible for breaking down food and absorbing nutrients. The jejunum is the middle section of the small intestine and is responsible for further digestion and absorption of nutrients. The ileum is the last section of the small intestine and is responsible for absorbing vitamins, minerals, and water. Together, these three sections of the small intestine work together to break down food and absorb nutrients.