Question

As food passes through the alimentary canal, the presence of chemical secretions will occur in which order?

Answer 1

The alimentary canal includes mouth, esophagus, stomach, small intestine, and large intestine. As food passes through the alimentary canal, it is exposed to the different chemical secretions from the organs of the alimentary canal, as well as from other organs, such as liver and pancreas.
First, in the mouth, salivary glands produce saliva which contains enzymes involved in the food digestions. After the food is passed to the esophagus, it produces mucus to help passage of the food. In the stomach, acid and pepsinogen, as well as mucus are produced. All of these secretions help food digestion. Small intestine also produces some digestive enzymes. Further, bile from liver and enzymes from pancreas are secreted via ducts into small intestine. Finally, large intestine secretes mucus for lubrication.