Three main nutrients in food: carbohydrates, protien and lipids; these are large molecules which are too large to be absorbed by the bloodstream so they therefore have to be digested
During digestion the large molecules are broken down into small molecules by enzymes which can then be absorbed into the bloodstream
1. Food is chewed in the mouth, enzymes in the saliva begin to digest the starch into smaller sugar molecules
2. The food then passes down into the oesophagus into the stomach, where enzymes begin to digest protiens. The stomach also contains hydrochloric acid which helps the enzymes to digest the protiens
3. The churning action of the stomach muscles turns the food into a fluid increasing the SA for enzymes to digest
4. The fluid now passes into the small intestine, where chemicals are then released into the small intestine from the liver and pancreas
5.The pancreas releases enzymes which continue the digestion of starch and protien.Also start the digestion of lipids.
6. The liver releases bile which helps to speed up the digestion of lipids. Bile also neutralises the acid released from the stomach
7. In the small intestine, the small food molecules are absorbed into the blood stream by diffusion or active transp. The walls of the intestine release enzymes to continue the digestion of prot+lips
8. The fluid makes its way through the large intestine where water is absorbed into the bloodstream+faeces are released
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