1. The Digestive System:
Process of Digestion
7SCIENCE Fri. Nov. 12

2. What happens in digestion?
• When food enters the mouth it is beginning
the process of digestion
• Two types:
– Mechanical
• Food is chewed and mixed in the mouth and mixes in
your stomach
– Chemical
• Breaks food down into many different, smaller parts so
they may be used by cells
• Takes place in the mouth, stomach and small intestine

3. In your mouth
• Tongue and teeth break food into smaller
pieces
• Tongue moves food around and mixes with
saliva
– Saliva is a type of
enzyme (chemical)
in the digestive
system that helps
to break food
down faster

4. In your esophagus and stomach
• No digestion takes place in the esophagus, food is
only moved to the stomach
• In the stomach, mechanical and
chemical digestion takes place
– Mechanical: food is mixed by
muscular walls
– Chemical: digestive juices break
down food
• Food takes about 4 hours to move
through your stomach!

5. In your small intestine
• In the small intestine: Other digestive
juices are added from the liver and
pancreas to break up nutrients like fat
– Think about adding soap to a
greasy/fatty plate
• Villi (finger-like) line the small intestine walls and nutrients
from
the small intestine
enter your blood
through the villi by
diffusion and osmosis

6. In your large intestine, rectum and
anus
• The remaining food particles enter
the large intestine and their main
job is to absorb the water from
the waste
• The solid waste is moved to the rectum and
when it is ready to be released, moves out the
anus