The Alimentary Canal is a continuous tube from mouth to anus, sometimes known as the DIGESTIVE TRACT. There are three main sections:
The mouth cavity, pharynx, oesophagus and stomach
The Small Intestine (duodenum, jejunum, and ileum)
The Large Intestine (caecum, colon, and rectum)
Food is taken in at the mouth, chewed and swallowed. It travels whilst being digested through the pharynx and then down the oesophagus into the stomach. where further digestion occurs. It then travels into the small intestine where it is digested and absorbed, and finally into the large intestine where water is absorbed and waste is excreted through the anus.
Both birds and dogs use DNA as instructions for building their bodies even though they are very different organisms because DNA of all the organism are made up of same four type of base adenine, thymine, cytosine, and guanine. These bases make genetic code that is universal in all the organisms.
Circular folds slow food going through the small intestine so the villi and microvilli can help the food to be processed and digested properly. Also, the presence of these circular folds increases the surface where the nutrients are being absorbed.
