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:
Ivan Mackerle
"sausage-like worm over half a metre (20 inches) long, and thick as a man's arm, resembling the intestine of cattle. Its tail is short, as [if] it were cut off, but not tapered. It is difficult to tell its head from its tail because it has no visible eyes, nostrils or mouth. Its colour is dark red, like blood or salami..."