small intestine

• divided into three sections - the duodenum, the jejunum, and the ileum
• the ileum is the space through which food passes
• the wall of the small intestine contains smooth muscle tissue, which rhythmically contracts (peristalsis) to move food along
• carbohydrate, protein and lipid digestion mainly occurs in the duodenum, with enzymes produced in the pancreas and small intestine itself
• soluble food molecules are absorbed into the bloodstream across the wall of the small intestine by diffusion and active transport - mainly in the jejunum and the ileum
• ileum is lined with villi to increase the surface area over which absorption can take place
• water absorption also occurs here