The Parts of the Digestive System There are a number of special organs in the digestive system.
Mouth
Salivary glands Oesophagus
z Fig. 8.2.2
The human digestive system
8.2
Liver
Stomach Pancreas
Small intestine Large intestine
Rectum Anus
1. Mouth zz
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Food is ingested through the mouth.
The teeth physically digest food and the enzymes in saliva chemically digest it.
There are four types of teeth: zz
Incisors: narrow, sharp teeth at the front of the mouth, similar to chisels. Used for biting, cutting and slicing food.
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Canines: pointed teeth, often called ‘eye teeth’. Used for grasping and tearing food.
Premolars: large, rounded teeth. Used for crushing and grinding food.
Molars: largest teeth, found at the back of the mouth. Also used for crushing and grinding food.
Salivary glands secrete saliva onto the food in the mouth. Saliva helps soften the food. Salivary amylase is the enzyme that chemically digests starch to maltose in the mouth.
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Food is swallowed and enters the oesophagus (food pipe).
Incisors z Fig. 8.2.3 The arrangement of human teeth Investigating salivary amylase
Plan, design, carry out and write up an investigation to examine the factors that influence the activity of salivary amylase.
