Human Digestive System
I have some questions on the human digestive system?
1. what is the function of the mouth in aiding digestion
2. what are digestive enzymes? Give examples
3.what is peristalsis
4. what is the role of the stomach in the digestion
5. What is the role of the small intestine in digestion of food
6. how does the pancreas aid digestion
7. what is bile and how does it aid digestion
8. why is the liver so important to a human
9. what is the role of the large intesine in digestion
1) the food the mechanically broken down in the mouth my chewing. salivary glands in the mouth releases amylase which begins the chemical break down of starch.
2) digestive enzymes are responsible for the breakdown of food into its simplest forms
eg. amylase (released by salivary glands and in the stomach) breaks down starch into monosaccharides. (enzymes are catalysts which speed up chemical reactions without being used in the reaction; therefore they are reuseable)
3) peristalsis is a wave movement/contractions which move sustances along; this occurs in the oesophagus and intestines, etc.
4) the stomach releases gastric juices which begin the breakdown of proteins (enzymes call pepsin is responsible for this), it churns and combines it into chyme
5) small intestines: three parts,
- duodenum (where bile emulsifies fats breaking lipids into glycerol and fatty acids, panease (released by the pancreas) breaks down proteins into amino acids, further break down of starch also takes place)
- ileum and jejum: up take of minerals and vitamins through villi which diffuses into the blood stream and lymphatic system.
6) the pancreas produces pancreatic juices which contain panease which breaks down the peptide bonds between proteins into amino acids.
7) bile is produced in the liver and stored in the gall bladder. it is not an enzyme but an emulsifier. it emulsifies lipids and breaks down it into fatty acids and glycerol.
liver is responsible for the production of bile salts which is EXTREMELY important; it emulsifies fats, if if the liver wasnt working fats can not be broken down
the liver also has many other functions whcih includes the filtration of blood.
9) large intestines also absorb minerals and vitimins (but limited amount) but it is responsible for the untake of water, leaving the substance as a semi-solid called faeces.