Digestive system. Artwork of a healthy human digestive system. Food is ingested through the mouth, where it is moistened with saliva from glands (pink). From here, food is moved down the oesophagus to the stomach (centre right), where it is stored and partially broken down ready before digestion in the small intestine (lower centre). The liver (centre left), gall bladder (green) and pancreas (yellow, behind stomach) add digestive enzymes and secretions to aid digestion. Food residue then passes into the colon, the main part of the large intestine (ribbed), where excess water is absorbed. Faeces are stored in the rectum (bottom centre), until they are expelled.