The document summarizes the key parts and processes of the human digestive system. It explains that food is ingested and then broken down through digestion, absorption, and assimilation before waste is egested. The main parts that work together are the alimentary canal (mouth, esophagus, stomach, intestines) and digestive glands like the liver and pancreas. Enzymes and acids in saliva and digestive juices break food down step-by-step as it passes through the system.

1. Our digestive system
Food eaten gives energy
But I do think ,
Is their any magic that
converts food into energy,
Or something that crushes it.
I asked my teacher all this ,
So do you know what she told
me??-

2. Nutrition
Nutrition is the process by which all living organisms obtain and
use food.
The food that we consume cannot be utilized by our body as it is .
Our body breaks it down into simpler form so that it can be
utilized by our body. This work of digesting the food by breaking it
down into simpler form is done by our Digestive system.

3. The process of nutrition
occurs in five stages -
Ingestion
Digestion
Absorption
Assimilation
Egestion
• Ingestion-food is taken into
the mouth .
• Digestion – the complex food
taken in through the mouth is
broken down into a simpler
form by the actions of
enzymes.
• Absorption - The digested
food is absorbed into the
blood stream.
• Assimilation – The digested
food is utilized by the blood or
stored for future use.
• Egestoin-The undigested
insoluble part is excreted in
the form of faeces.

4. Digestive system
The system by which ingested food is acted upon by physical
and chemical means to provide the body with absorbable
nutrients and to excrete waste products; in mammals the
system includes the alimentary canal extending from the mouth
to the anus, and the hormones and enzymes assisting in
digestion.

5. There are mainly two parts in a
digestive system.
• Alimentary canal
It is a long tube like
muscular structure that
runs from the mouth to
the anus. It consists of
mouth, pharynx,
esophagus , stomach ,
small intestine, large
intestine, rectum and
anus.
• Digestive glands
The digestive system
associated with the
alimentary canal are the
salivary glands , liver and
pancreas.

6. Alimentary canal-Mouth
• Food starts its journey from
the mouth or the oral cavity.
There are many other
organs that contribute to
the digestion process,
including teeth, salivary
glands, and tongue. Teeth
are designed for grinding
food particles into small
pieces and are moistened
with saliva before the
tongue pushes the food into
the pharynx.

7. Teeth
• Teeth are one of the strongest parts of the
human body. It is mainly composed of proteins
(collagen) and minerals (calcium). An adult will
have 32 teeth, including the Wisdom
teeth. Molars are the first permanent teeth to
develop in, and most of the adults will have
their complete set of permanent teeth in
place by the age of 21.Overall adults have 32
teeth in total, called permanent or secondary
teeth, and it includes:
• Eight incisors – Four incisors in the upper jaw
and four incisors in the lower jaw.
• Four canines – Two canines in the upper jaw
and two canines in the lower jaw.
• Eight premolars– Four premolars in the upper
jaw and four premolars in the lower jaw.
• Twelve molars- Six molars in the upper jaw and
six in the lower jaw. It also includes four wisdom
teeth.
• Babies are born toothless as their primary
source of food is mother’s milk.

8. Pharynx
• Pharynx a fibromuscular y-
shaped tube attached to the
terminal end of the mouth.
It is mainly involved in the
passage of chewed/crushed
food from the mouth
through the esophagus. It
also has a major part in the
respiratory system, as air
travels through the pharynx
from the nasal cavity on its
way to the lungs

9. Esophagus
• Esophagus is a muscular
tube that connects the
pharynx. It supplies
swallowed food along
with its length. The
muscles contract one
after the other in a
wave – like motion
known as Peristlises.

10. Stomach
• Thee stomach is a sac-like
organ with strong
muscular walls . It can
store food for several
hours. In the stomach
gastric juices secreted
by stomach breakdown
the food further into
paste.
From stomach food
moves to small intestine.

11. Small Intestines
• The small intestine
The small intestine, or small
bowel, is a hollow tube
about 20 feet long that runs
from the stomach to the
beginning of the large
intestine. The small intestine
breaks down food from the
stomach and absorbs much
of the nutrients from the
food.

12. Large intestine
The long, tube-like organ that is
connected to the small intestine at
one end and the anus at the other.
The purpose of the large intestine is
to absorb water and salts from the
material that has not been digested
as food, and get rid of any waste
products left over. By the time food
mixed with digestive juices reaches
your large intestine, most digestion
and absorption has already taken
place. It has 3 main parts caecum ,
colon and rectum. Rectum is a short
tube that opens outside through the
anus. The opening between a
person's buttocks through which
solid waste passes from the body.

13. Digestive glands- Salivary glands
There are three types of salivary
glands that open in our mouth.
Saliva helps with swallowing and
chewing. It can also help prevent
infections from developing in your
mouth or throat.

14. Liver
• The liver is an organ about the
size of a football. It sits just under
your rib cage on the right side of
your abdomen. The liver is
essential for digesting food and
ridding your body of toxic
substances. Bile is a fluid that is
made and released by the liver
and stored in the gallbladder.
Liver produces bile which is a
greenish yellow liquid. Bile helps
with digestion. It breaks down
fats into fatty acids, which can be
taken into the body by the
digestive tract.

15. Pancreas
The pancreas makes panc
reatic juices and
hormones. The pancreatic
juices contain enzymes
that help digest food in
the small intestine