The small intestine is a tube about six metres long that joins the stomach to the large intestine. It is coiled up in the centre of the abdomen.
• Chyme passes into the duodenum from the stomach, where two digestive juices – bile and pancreatic juice – flow into the chyme.
• Bile is produced by the liver and stored in the gall bladder. It breaks the fat down into tiny droplets.
• The pancreatic juice contains three enzymes that help break down the starch, fat and protein. Liver
Discovery Learning Can you find out what enzyme is in bile and explain how it works? In pancreatic juices there are three enzymes – can you name them and explain what each does?
Gall Stomach bladder Pancreas Duodenum Food being broken down in the small intestine
The chyme is pushed along the small intestine by the action of peristalsis. Intestinal juice produced in the walls of the small intestine completes the breakdown of proteins, fats and carbohydrates.
Serosa
Absorption • These juices are then able to enter the intestinal wall by absorption, where the soluble, digested food passes into the bloodstream.
• The lining of the small intestine is folded and has little finger-like projections called villi, which increase the area for absorption. The surface is only one cell
Villus
Submucosa Mucosa
Villi
Muscle layers
Artery
Vein Villi in the small intestine thick, which speeds up the absorption of nutrients.
• These nutrients are carried by the blood to all the cells of the body, where they are used to provide energy and make new cells.
• The remaining materials then pass into the large intestine. 50
Strand 1: Food, Health and Culinary Skills Section 2: Nutrition Know-How
