The ileum: The final section of the small intestine. It is about 3 m long, and contains villi similar to the jejunum. It absorbs mainly vitamin B12 and bile acids, as well as any other remaining nutrients. The ileum joins to the cecum of the large intestine at the ileocecal junction.Click to see full answer. Likewise, what are the parts of the small intestine?The small intestine consists of three parts. The first part, called the duodenum, connects to the stomach. The middle part is the jejunum. The third part, called the ileum, attaches to the colon.Secondly, how long is each part of the small intestine? The length of the small intestine can vary between about 10 feet (3 meters) to over 16 feet (5 meters). For comparison, a standard basketball hoop is 10 feet tall. The different sections of the small intestine are also different lengths. The ileum is the longest section while the duodenum is the shortest. Also to know, what is the top portion of the small intestine called? Small Intestine. The jejunum is the upper part of the small intestine and the ileum the lower part, though there is no clear delineation between the jejunum and ileum.What are the functions of the 3 parts of the small intestine?The three main regions of the small intestine are the duodenum, the jejunum, and the ileum. The small intestine is where digestion is completed and virtually all absorption occurs.