Grade Saved


Your grade

Digestive system





In the mouth

Saliva is slightly alkaline.

Enzymes in saliva convert starch into glucose:

- amylase catalyses: starch → maltose

maltase catalyses: maltose → glucose [2]


After it has been in the stomach, food travels to the small intestine.

Bile and enzyme production in the liver and pancreas

The enzymes in the small intestine work best in alkaline conditions (but the food is acidic after being in the stomach).

Bile is a substance produced by the liver and stored in the gall bladder. [5]

Organs and their functions

Mouth - Where food enters the alimentary canal and digestion begins

Salivary glands - Produce saliva containing amylase

Stomach - Muscular organ where digestion continues

Pancreas - Produces digestive enzymes

Liver - Produces bile

Gall bladder - Stores bile before releasing it into the duodenum

Small intestine - duodenum - Where food is mixed with digestive enzymes and bile

Small intestine - ileum - Where digested food is absorbed into the blood and lymph

Large intestine - colon - Where water is reabsorbed

Large intestine - rectum - Where faeces are stored

Large intestine - anus - Where faeces leave the alimentary canal [1]

In the stomach

The stomach produces hydrochloric acid.

It kills many harmful microorganisms that might have been swallowed along with the food.

The enzymes in the stomach work best in acidic conditions – at a low pH. [3]

Effects of bile

- neutralises the acid - (providing the alkaline conditions needed in the small intestine)

- emulsifies fats - (providing a larger surface area over which the lipase enzymes can work) [4]







You may be interested in

© 2017