Give a basic overview of the of the digestive system.

The digestive system is a tube starting from the mouth and ending at the anus. Between are different compartments with different roles. The first stage of digestion occurs in the mouth. The teeth grind the food down into smaller pieces to increase the surface area. Also, saliva is released in the mouth which contains mucus to soften the food and amylase enzyme to break down starch into glucose. Next it travels through the oesophagus into the stomach. Here protease is produced to break down proteins into amino acids. HCl is produced to provide acidic conditions for protease and assists in immunity by killing bacteria. The stomach contracts and churns the food to break it down and also allow it t mix with the acid and enzyme.Once released from the stomach the food enters the small intestines where chemical digestion occurs. The pancraese is separate and not part of the "tube" as mentioned before, it releases enzymes into the small intestines. Carbohydrase enzymes break down carbohydrates into glucose. Protease break down protein into amino acids. Lipase breaks down lipids into glycerol and fatty acids. The liver is also seprate to the tube and secretes bile into the small intetsines. It breaks down fat into smaller pieces to increase the area for enzymes to work on as well as neutralise the acid from the stomach. The products of digestion are absorbed into the blood via villi. Villi are projections on the inner wall of the small intestines which increase the surface area for absorption. The remaining food enters the large intestines where water is absorbed and bacteria release enzyme to help absorb vitamins and minerals. The remains which is mainly fibre is stored in the rectum and eventually released through the anus.