- Digestion is the process by which food is broken down into soluble substances that can be absorbed in the blood stream.
- Digestion starts from the mouth and ends in the
TYPE OF DIGESTION
There are two types of digestion;
- Mechanical digestion.
- Chemical digestion
- This is the process of breaking down food into small particles by the help of teeth.
- It takes place in the mouth in human beings.
- This is the process of breaking down food by the help of chemical compounds called
- Chemical digestion starts in the mouth and ends in the ileum.
- Enzymes are chemical substances that speed up the rate of digestion.
Characteristics of enzymes.
- They are protein in nature.
- An enzyme always forms the same end product.
- They are specific i.e. each enzyme acts upon one class of food.
- They are destroyed by heating.
- They act in particular conditions i.e. some prefer acidic, others alkaline
Conditions under which enzymes work.
- They work best in temperatures below 40o
- They can easily be destroyed by heat above 40o c
- Pepsin and rennin work best in acidic conditions.
- Trypsin, amylase, lipase and intestinal enzymes work best in alkaline conditions.
THE ALIMENTARY CANAL AND THE DIGESTIVE SYSTEM
The alimentary canal.
- The alimentary canal is a muscular tube that runs from the mouth to the anus.
- The alimentary canal is about ten metres in an average adult person.
Parts of the alimentary canal.
- Gullet (oesophagus)
- Small intestine.
- Large intestine