Page 126 - Primary Five Science

Digestion

Digestion is the process by which food is

broken down into a simpler soluble parti-

cles so that it can be absorbed by the body.

The digestive system is a group of organs

that work together to carry out digestion
and absorption of food.

It is made up of an alimentary canal with
other associated organs like the liver and

the pancreas.

The alimentary canal is a muscular tube

running from the mouth to the anus. It is

about 10m long.

Digestion may be mechanical or chemical.

Mechanical digestion is where food is break-

down into smaller particles physically or mechanical-

ly for example by processes such as chewing by the teeth

or churning of food by the stomach.

Chemical digestion is where food is broken down to simpler

soluble particles by action of enzymes. These enzymes are secret-

ed by digestive system organs.

Enzymes are substances secreted by the body to speed up

chemical reactions in the body. Without enzymes, the reactions

would be too slow for the body to benefit.