The mouth contains salivary glands which release saliva. When food enters your mouth the number of saliva increases. Saliva helps to lubricate food and contains chemicals (enzymes) that start chemically digesting your meal. Teeth break down large chunks into smaller bites. This gives a greater surface area for the body’s enzymes to work on. Saliva also contains special chemicals that help to stop germs (bacteria) from causing infections. The amount of saliva released is controlled by your nervous system.

A certain amount of saliva is normally continuously released. The sight, smell or thought of food can also stimulate your salivary glands. To pass food from your mouth to the gullet (esophagus) you must be able to swallow. Your tongue helps to push food to the back of the mouth. Then the passages to your lungs close and you stop breathing for a short time. The food passes into your esophagus. The esophagus releases mucus to lubricate food. Muscles push your meal downwards towards the stomach.