Students learn that the small intestine is divided into three parts. The first segment is the duodenum, the second segment is the jejunum, and the third segment is the ileum. The duodenum receives digestive enzymes from the pancreas and bile from the gallbladder. These substances aid digestion by breaking down certain food particles.
Most absorption occurs in the second and third parts of the small intestine, the jejunum and the ileum. Absorption is facilitated by peristalsis and the surface area of the villi. Enzymes continue to be released in small amounts, along with water from the intestinal walls, to dissolve the remaining food.