Can anyone explain to me the process of the digestive system please!?!
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igcse biology watch
- Thread Starter
- 09-05-2015 19:23
- 10-05-2015 00:10
Ingestion is putting food into your mouth. In your mouth, food is mechanically digested by the chewing movement created by our jaw action. It is also partially digested by saliva as saliva contains amylase, which breaks down starch into maltose. A bolus (ball of food covered in saliva) is created so food is lubricated for easy swallowing. The bolus passes down the oesophagus (the muscular tube connecting the mouth and stomach) into the stomach. In the stomach, the muscular walls of the stomach pummel food (churning) to mechanically digest food. The stomach also produces the protease enzyme, pepsin. The stomach contains hydrochloric acid to kill bacteria and give the optimum pH for pepsin to work at. Food then moves into the small intestine. The pancreas produces pancreatic juice, containing protease, amylase and lipase- it releases this into the small intestine. In the small intestine food is broken down into smaller molecules (Note that amylase converts starch into maltose, maltase converts maltose into glucose, protease converts proteins into amino acids and lipase convert lipids into fatty acids and glycerol), absorbed (Absorption is the process of moving small food molecules into the blood through the walls of the small intestine) and assimilated (Small food molecules are used to build large molecules e.g. amino acids are used to make structures in cells). The large intestine absorbs water from undigested food, producing faeces. Faeces are egested (removed through the anus).
If you need info on peristalsis, bile or the villi then ask. I am assuming u are doing edexcelLast edited by Naveen1412; 10-05-2015 at 00:13.