Gastrointestinal tract
The small intestine begins at the duodenum and is a tubular structure, usually between 6 and 7 m long. Its mucosal area in an adult human is about 30 m. Its main function is to absorb the products of digestion (including carbohydrates, proteins, lipids, and vitamins) into the bloodstream. There are three major divisions:
Chitterlings
Both large and small intestine (typically pig) is eaten throughout China. Large intestine is called "feichang", literally "fat intestine" because it is fatty. Small intestine is called "zhufenchang", literally "pig powder intestine" because it contains a white, pasty or powdery substance. The character "zhu" or "pig" is added at the beginning to disambiguate. This is because, in Cantonese cuisine, there is a dish called "chang fen" which uses intestine-shaped noodles.