The small intestine consists of the duodenum, jejunum and ileum. The small intestine is subdivided into the duodenum, the jejunum and the ileum. The jejunum and ileum receive blood from the superior mesenteric artery. The jejunum and ileum are suspended in the abdominal cavity by mesentery. Carcinoid tumors of the midgut (jejunum, ileum, appendix, and cecum) are associated with carcinoid syndrome. The small intestine is divided into 3 parts&colon; duodenum, jejunum and ileum. The villi in the jejunum are much longer than in the duodenum or ileum. Vitamin B is absorbed in the jejunum and ileum by passive diffusion. The digestive tract continues as the jejunum which continues as the ileum. It has three parts, the duodenum, jejunum and ileum. The division between the jejunum and ileum is not anatomically distinct. There is no line of demarcation between the jejunum and the ileum. S cells are cells which release secretin, found in the jejunum and duodenum. Inflammation usually occurs in sections of the jejunum, midsection of the small intestine. This is usually the stomach or part of the large intestine (colon) or jejunum.