Small intestine
The small intestine is a major digestive organ which absorps vital nutrients. It is the longest part of the gastrointestinal tract and can be seprated into three parts - the duodenum, jejunum and the ileum[1]. The duodenum is responsible for the breakdown of food. It has the widest lumen of the small intestine and itself is split in to four parts, the superior part, the descending part, the inferior part and the ascending part[1]. The jejunum is smaller in diameter than the duodenum and absorps carbohydrates and sugars. The illeum is smaller still than the jejunum and absorbs what is not digested by the jejunum such as vitamin B12.