Download Digestive System

T.Marwa Maged





Identify the importance of eating food.
Identify the functions of the digestive system.
Differentiate between mechanical and chemical
digestion.
Identify the organs of the digestive system.
Identify the process of digestion.


The food we eat contain important substances that body
needs to grow and carry on important processes.
Body can’t carry on important functions without continuous
supply with food, even when we sleep we continue using
those substances but with no replacement so good breakfast
is important to restore the body supply of the materials it
needs .




Body cells cant use most foods until they are
broken down into smaller substances.
Organs of the digestive system work together to
break down food into usable form.
Digestion :
Breaking down food into smaller substances that
can be used by the body
Mechanical digestion
-Occurs by grinding , mashing
food
Example : By teeth in the mouth .




Chemical digestion
Chemicals called enzymes help
break down food into nutrients
Example : digestive enzymes
produced by stomach.
Enzymes : are chemical substances produced by digestive
system to break food into smaller substances
Organs of the digestive system :
1- organs of the digestive tract :
Mouth, esophagus, stomach , small intestine, large intestine.
2- Organs outside of the digestive tract :
liver , gall bladder , pancreas

1- Mouth
Mechanical
 Digestion
1-Teeth shred food
2-Tongue mixes the food
with saliva.

Chemical
Digestion
Salivary glands
produces saliva
Which is a mixture
of water and enzymes
that starts digesting
starch to simple sugars
Under electron microscope , the
surface of the tongue has red
structures called taste buds
Smaller finger like projections
forming a rough surface on the
tongue helps in the chewing and
movement of food .
2- Esophagus :
-The tongue pushes the moist food to
The esophagus , smooth muscles
contraction
Of esophagus push the food to stomach
Mechanical
 Digestion
By Squeezing its
Content with
muscular contractions

Chemical
Digestion
glands in stomach
produces enzymes
and acids that
breaks down proteins
acids kills bacteria that
enters with food ,
food stay in
stomach (2-5hours)
In the electron microscope
image of stomach , oval cells
appear that line stomach
producing mucus that protect
stomach from digestive
substances , pits in the lining
contains glands that produces
digestive juices.
4- Liver:
produces bile that helps
digest fat (liver also
stores some nutrients
and break down
harmful substances
in the blood )
5-Gall bladder:
Bile produced by the liver are stored in the
gallbladder until it is released to the small
intestine when needed.
6- Pancreas :
Produces enzymes that
flow into small intestine
that neutralize stomach
acids that is mixed with
food that enters small
intestine.
Materials that can’t be
absorbed into blood stream
pass to the large intestine
-Little digestion takes place
-It absorbs water from the
undigested material and stores
solid waste until they leave the
body.