The jejunum and ileum are the second and third parts of the small intestine. The jejunum forms a little less than half of the length of the small intestine, and it can be recognized by a wider diameter and deeper red color as it contains more blood vessels than the ileum. The jejunum and ileum are surrounded by the large intestine. They are intraperitoneal organs located within the peritoneal cavity - the peritoneum covers them from all sides.