The Mouth consists of:Oval shaped cavityTeethTongueMain function is to break down food mechanically and chemically.Mechanical digestion occurs when food is being chewed. The teeth act as a grinder. It chops and grinds the food into small pieces to make it easier to be swallowed.Chemical digestion occurs when the food is mixed with amylase (enzyme in saliva) which is secreted from salivary gland. Amylase begins the breakdown of carbohydrates (starch).The Pharynx is the passageway for mouth to esophagus. Main function is to swallow food to allow it to travel from the mouth to the oesophagus to be further digested.The Oesophagus is a long muscular tube lined with mucosa. The oesophagus main function is to transport food to the stomach.The Stomach is a bean shaped sack with thick muscular walls.Its main function is to further break down and digest food to extract nutrients to be absorbed by the body. Mechanical digestion in the stomach is called segmentation. This is the churning action that breaks down food. Chemical digestion occurs when the stomach secretes hydrochloric acid (HCl) and enzymes such as pepsin and lipase. Secreted from gastric gland. This extracts nutrients from the food being digested.The Pancreas is a large gland. Its main function is to convert food into fuel for body.Chemical digestion secretes digestive fluids to further digest food.The Liver is a large organ. Its main function is produce bile to emulsify food. The liver also stores glucose for later use. The liver also stores vitamins and mineralsThe Gallbladder is a small sack. its main function is to store bile and regulate its pH level.The small intestine can be split into three parts:- Duodenum-Jejunum-IleumThe small intestine is lined with villi and microvilli, it also has many mucosal folds.The main function of the small intestine is to absorb nutrients from food.-duodenum: Mixes food with enzymes and bile-Jejunum: absorbs food nutrients that the body needs-Ileum: absorbs bile acid and vitamin B12, connects to the large intestineThe large intestine is a long muscular tube.Its main function is to absorb water from remaining food and transport waste products out of the body.The rectum is the last section of the large intestine before the anus. Its main function is temporarily store faeces before it is passed out through the anus.