The human digestive system breaks down food mechanically and chemically so that nutrients can be absorbed and used by the body. Food passes through a series of organs, being broken down by enzymes and acid. The mouth, esophagus, stomach, small intestine, large intestine, rectum and anus all play a role in digestion. In the stomach, food is broken down by acid and enzymes. In the small intestine, the pancreas, liver and intestinal glands further break down food into molecules that can be absorbed. Undigested material then passes to the large intestine, where water and minerals are absorbed before waste is passed through the rectum and anus.

1. HUMAN DIGESTIVE SYSTEM

2. What is the Digestive System ?
 Digestion essentially occurs in a series of tubes such as
the Oesophagus and Intestines as food passes through
the body. A number of other organs contribute to
digestion by providing enzymes for the breakdown of
food.

3. The Functions of the Digestive
System.
• The primary function of the digestive system is to break
down food both mechanically and by the use of enzymes, so
that it can be used by the body for energy and cell growth
and repair. The human digestive system consists of a large
number of organs and processes with the combined
functions of breaking down our food into smaller molecules
which can be used to produce energy and for other
nutritional purposes; and excreting the waste consumed
and produced by the system.

4. Mouth: The
mouth is the
starting point of
digestion. Here the
process of chewing
starts to break down
food and enzymes
such as salivary
lipase and amylase
also start to
chemically break
down the food.

5. Oesophagus:
Once you swallow
the food moves into
the Oesophagus
where continual
waves of involuntary
contraction push the
food into the
stomach.

6. Stomach:The stomach
has both a mechanical and a
chemical function in digestion.
The upper part of the smooth
(voluntary)stomach muscle
relaxes to allow a large volume of
food to be stored. The lower
muscle then contracts in a
rhythmical manner in order to
churn the food inside and mix it
together with the gastric acid
(mainly hydrochloric acid) and
digestive enzymes Pepsin,
Gelatinase and Gastric Amylase
and Lipase which break it down
further. The stomach must then
empty its contents into the small
intestine.

7. Small Intestine:Whilst
in the small intestine food is
subjected to yet more enzymes,
those from the Pancreas and
from the glands within the
intestine walls which break
down carbohydrates and
proteins. It is also mixed with a
product of the liver which is
stored and released into the
intestine by the gall bladder.
This is commonly known as
bile. Bile works to dissolve fat
so that it can be digested by the
other enzymes.

8. Large
Intestine: The large
intestine continues the
foods journey and is the
bodies last chance to
absorb any water and
minerals still remaining.
The rest of the contents
of the large intestine is
waste such as
undigestable pieces of
food and fiber. This is
passed through to the
rectum where it is stored
until you go to the toilet!

9. Rectum :As being the
last part of the digestive tract,
the rectum acts as a temporary
storage facility for waste
material. The food we eat
undergoes the process of
digestion once we start chewing
it in our mouth then it is passed
on to stomach, small intestines
and finally large intestine, the
remaining residue of undigested
food with bacteria and the juices
from the digestive system enter
the rectum in the form of faeces.
These faeces remain in rectum
until we proceed with defecation
in which through bowel
movement they are transferred to
anal canal and then outside of
the body.

10. Anus: The anus is the
last 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).
The lining of the upper
anus is specialized to
detect rectal contents. It
lets you know whether
the contents are liquid,
gas, or solid. The anus is
surrounded by sphincter
muscles that are
important in allowing
control of stool.

11. Preparedby:
TARUL
X–A
II Shift