2. Review
In Grade 6, the students learned how
the different organ systems work together.
In Grade 7, they were introduced to the
levels of organization in an organism of
which, organ systems but a part.
In Grade 8, the students will learn not
just the structures of certain organ systems
that work together but also the processes they
undertake to keep the state of balance in
organisms.
4. DIGESTIVE SYSTEM
-is one of the important
organ systems of an organism. It
is responsible for the
breakdown of foods which are
made up of nutrients and can be
converted into an energy.
5. Four Major Functions of the
Digestive System
1. ingestion of food
2. digestion of food
3. absorption of nutrients
4. elimination/excretion of waste
materials
6. Ingestion
-the process of taking
food, drink, or other
substance into the body
by swallowing or
absorbing it.
8. Two Phases of Digestion
1. Mechanical/Physical phase happened
when the food is broken down into
smaller pieces in the process known
chewing and mastication. The action of
the digestive juices, such as saliva in the
mouth and the gastric juice in the
stomach, lubricate and soften the food.
9. Two Phases of Digestion
2. Chemical phase happened when food
is acted upon by chemical substances
called enzymes that are secreted together
with the digestive juices and the saliva.
These enzymes converted the food into
their simplest equivalents which the
body cells can utilize.
10. Digestive Enzymes
a. Salivary amylase (starch into maltose)
b. Pancreatic amylase (completes the
digestion of carbohydrates to produce
glucose)
c. Protease (the breakdown of proteins into
amino acids.
15. Mouth or oral cavity-
is the beginning of the
digestive tract, the
teeth, mechanically
break down food that is
mixed with saliva. The
food is pushed about by
the tongue; the tongue’s
taste buds provide the
pleasurable sensation of
taste.
17. Esophagus — The food
product is carried further
through the canal by
peristalsis into the stomach.
No digestion takes place in
either the pharynx or the
esophagus. The lower
esophageal sphincter (LES),
or cardiac sphincter, relaxes
to allow food into the
stomach; it then contracts,
preventing the backup of
stomach contents.
18. Stomach
A stretchy bag that holds
your food after you eat
Helps to break food into
smaller pieces so your body
can use it for energy and
nutrition
19. Small Intestine
Tube that is 20 feet long.
Continues to digest food
Food stays in your small intestine for 4
to 8 hours
20. The duodenum is the first
segment of the small
intestine. It’s largely
responsible for the
continuous breaking-down
process. The jejunum and
ileum lower in the intestine
are mainly responsible for
absorption of nutrients into
the bloodstream.
Digestion is completed
also in the small intestine.
21.
22. Gall Bladder
Storage tank for bile (a greenish-yellow
liquid) that helps your body break down and
use fats
Located under your liver
Shaped like a pear
30. Rectum- a straight, 8-inch
chamber that connects the
colon to the anus. It
receives stool from the
colon.
Anus- the end part of the
digestive tract. It is a 2-
inch long canal consisting
of the pelvic floor muscles
and the two anal sphincters
(internal and external)
where our stool or feces
expelled.
