Grade Eight - The Human Digestive System

1. HUMAN
DIGESTIVE
SYSTEM

2. DIGESTIVE SYSTEM
It is responsible for
breaking down the food
mechanically and chemically
to convert complex
molecules into the simplest
units, a fraction of which is
made up of nutrients that the

3. THERE ARE TWO (2) TYPES
OF DIGESTION:
1. Mechanical Digestion - food
is chewed and broken down
into smaller pieces for easier
digestion.
2. Chemical Digestion - this is
carried out by enzyme
(amylase) molecules that

4. MOUTH
The tongue
mixes the foods,
and the teeth
break down the
foods into small
pieces and the
saliva secreted
by the salivary

5. PHARYNX
It connects the
nasal and oral
cavities of the
body. After
chewing the
food, it
transports the

6. ESOPHAGUS
It is a muscular
tube that is
approximately
10 inches in
length. It serves
as a passageway
of food to the

7. STOMACH
The stomach is
made up of
muscles that
churn and help to
mix and to break
food into even
smaller pieces.
Stomach juices

8. PANCREAS
The pancreas
secretes
pancreatic juice
which breaks
down fats,
carbohydrates,
and protein. It also
releases insulin
into the blood that

9. LIVER
It produces bile
that helps to
break fats into
smaller ones.
This bile is
stored in the
gallbladder and
it releases bile

10. LARGE AND SMALL
INTESTINES
The large intestine
connects the small
intestine to the
anus. Waste food or
substances that
need to be removed
from the body are
stored here. It also
changed waste into

11. ANUS
It is the way of the
semi-solid waste
or feces out of the
body.

12. DIGESTION PROCESS

13. The first process of digestion is
called…
1. Ingestion - starts when food is
taken into the mouth.
– Then the food passes through the
esophagus. Muscle contractions in
the esophagus help move the food
down to the stomach. This process
is called peristalsis.

14. The second process of digestion
is called…
2. Absorption and Assimilation
– During absorption and
assimilation, these nutrients pass
through the walls of the intestine and
into the bloodstream, where they get
transported to the different parts of
the body. It helps in cell growth and
development and new cell
production.

15. The third process of digestion is
called…
3. Excretion
- The undigested parts of food or
those that were not absorbed by the
body moves to the large intestine as
it also changes the undigested food
into semi-solid waste or feces which
leave the body through the anus.