Tags: Anatomical Structure.
Into the human digestive system the process of digestion has many stages the first of which starts in the mouth (oral cavity). Digestion involves the breakdown of food into smaller and smaller components which can be absorbed and assimilated into the body. The secretion of saliva helps to produce a bolus which can be swallowed in the oesophagus to pass down into the stomach. Saliva also contains a catalytic enzyme called amylase which starts to act on food in the mouth.