The liver and digestion

• The major nutrients required for a healthy diet are carbohydrates, proteins and lipids.
• The digestive system breaks down large molecules of food, which are then absorbed into the bloodstream.
• The liver, a large organ beside the stomach, has many functions, including processing substances absorbed by the digestive system and a role in the storage of the body's carbohydrate.
• The liver does not secrete any enzymes, but it plays an important role in digestion.
• Digestion involves the breakdown of large insoluble food molecules to smaller soluble ones, and then processing food molecules.
• A molecule is a collection of two or more atoms held together by chemical bonds that have been absorbed.
• Absorption is when a substance is taken in by something or moved across a barrier such as a cell membrane, it is said to have been absorbed.
• The liver produces bile, a substance produced in the liver, which emulsifies fats to prepare them for digestion.
• Bile emulsifies by mixing water with fats and oils to produce a cloudy mixture called an emulsion.
• Lipids are fat or oils, composed of fatty acids and glycerol, which are broken up physically into tiny droplets.
• Tiny droplets have a much larger surface area, over which lipases can work, than larger pieces, or drops of lipid.
• Sodium hydrogencarbonate, an alkali, is produced in the liver, but stored and concentrated in the gall bladder.
• The gall bladder stores bile before releasing it into the duodenum.