The small intestine is where most of the digestion and absorption occur. The small intestine is a long tube about 6.35 m (21 ft) long and 2.5 cm (1 in) in diameter. It is divided into three sections; the duodenum (doo- oh- DE- num) which is about 25cm (10 in) long, the jejunum (jee- JOO- num) in the middle which is about 1 meter (3 ft) long, and finally the ileum (IL- ee- um) which measures 2 m (6 ft) in length. The small intestine begins at the pyloric sphincter and coils through the central and lower part of the abdomen where it eventually opens into the large intestine by way of the ileocecal (il- ee-oo- SEE- kal) sphincter.