Organs of the digestive system
The digestive system is an organ system: several organs work together to
digest food into small soluble molecules and absorb them
into the blood
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The digestive system mouth stomach pancreas liver salivary glands make AMYLASE (a carbohydrase) oesophagus stomach makes PROTEASE and hydrochloric acid — the low pH is what the protease needs, and it kills bacteria the muscular wall churns the food pancreas makes amylase, protease and lipase large intestine water is absorbed here, leaving faeces liver makes BILE — alkaline, so it neutralises stomach acid, and it EMULSIFIES fat into small droplets, giving lipase a bigger surface area to work on gall bladder — stores the bile small intestine makes more enzymes, and this is where the soluble products are absorbed villi give a huge surface area, with a thin wall and a good blood supply Carbohydrase breaks starch into simple sugars, protease breaks protein into amino acids, and lipase breaks lipids into fatty acids and glycerol. Big insoluble molecules have to be broken into small soluble ones before they can be absorbed into the blood. The digestive system with the mouth and salivary glands, oesophagus, stomach, liver, gall bladder, pancreas, small intestine and large intestine labelled, and the enzyme made at each site
Organ
What happens there
Mouth teeth break food up; salivary glands make amylase
Stomach muscular walls churn the food; makes protease (pepsin) and hydrochloric acid , which kills bacteria and gives the low pH pepsin needs
Liver makes bile
Gall bladder stores bile and releases it into the small intestine
Pancreas makes amylase, protease and lipase, released into the small intestine
Small intestine makes more enzymes; digestion is completed; the products are absorbed through the villi into the blood
Large intestine water is absorbed; faeces formed
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In the full topic
• Organs of the digestive system• Digestive enzymes• Bile• AbsorptionRead the free biology topics →