The alimentary canal is a long hollow tube which runs from the mouth to the anus .Together with several other organs, including the liver and the pancreas, it makes up the digestive system.
The total length of the human alimentary canal is between 5 and 6 m, from anus to mouth. To fit this considerable length into body, parts of the canal are folded and coiled inside the abdomen .The mucus is a substance secreted along the tube by cells lining its walls .Mucus helps food to slide through the canal without doing too much damage to the lining. It also forms a protective covering which keeps the digestive juices, which are inside the lumen of the canal, from coming into contact with the living cells of the walls. Along the whole length of the alimentary canal there are muscles in the walls. These produce waves, of
Contraction and relaxation called peristaltic waves, which move food along the alimentary canal and help to mix the contents. Each region of the alimentary canal has it own function and different structure. There are 4 basic layers in the wall of the alimentary canal. Working from the inside these are: a) the mucosa b) the submucosa c) the muscularis externa d) the serosa. Many of this names came from Latin origin.