The document summarizes the mammalian digestive system. It describes the main components of the system including the mouth, esophagus, stomach, small intestine, pancreas, large intestine, liver, and their functions. The digestive process begins with ingestion and mechanical breakdown of food in the mouth. Enzymatic digestion then occurs as food moves through the stomach, small intestine, pancreas and liver. Nutrients are then absorbed and assimilated for use by the body. Undigested waste is eliminated through the large intestine and rectum.

1. B Y S A A D A D I L
Nutrition In Mammals

2. Holozoic Nutrition
 Animals feed by ingesting ready-made complex
organic matter obtained from other organisms.
This mode of feeding on ready-made complex
organic matter is called holozoic nutrition

3. Mammilian Digestive System
The mammilian digestive system consists of the
Gut(Alimentary canal) & Glands associated with it
.Food substances are digested in the alimentary
canal . The tubular gut extends from the mouth
to the anus ,most of its length coiled in the
abdominal cavity .

4. When Food Enters The Mouth
 Food enters the body via the mouth which leads in to
the Buccal cavityare the upper & lower jaws . The
upper jaw is fixed while the lower is movable. These
jaw bear four tipes : Incisors,Pre mollars,Molars &
Canines.
 In the mouth the solid food is broken up into small
pices by chewing action of teeth. The tounge has
special sense cells & taste buds which helps you to
select suitable foods. Three pairs of salivairy glands
open into the buccal cavity via duct. They produce
secretion called saliva which is empitied into the
buccal cavity.

5. Human Digestive System

6. Pharynx
 The pharynx is the part of the gut which leads
mouth to the esophagus and to the trachea by
way the larynx . The larynx bears alit-like
opening called the glottis.

7. Epiglotis
 Possibility of food passing into the trachea during
solowing usually prevented by a piece of flap like
cartilage , the Epiglotis.
 The epiglotis is above larynx just behind the roof
of the tounge.

8. Breathing

9. Oesophagus
 Each food passes down the esophagus to the stomach with help of gravity. It is
also known as Food pipe. It is a pipe starting from mouth & ending on stomach.

10. Layers of Oesophagus
 The outermost layer is a thin membrane known as the serous coat. It is moist & slippery, so
that friction is reduced when the organs slide over one another.
 Next to this are the muscle layers consisting of an outer layer of longitudinal muscles. These
are called smooth muscles. Their contractions are slow & sustained.
 Then comes a blood vessels & connective tissues called the submucous coat.
 The innermost layer is the mucous layer. It is folded extensively & contains gland cells, some
of which secrete mucus which lubricates the food so it moves more easily along the gut.

11. Stomach
 The mucous coat of the stomach walls bears numerois pits , the walls of which are
lined with Gastric Glands. These glands secrete gastric juice which plays an
important part in digestion.

13. Small Intestine
 The small intestine consists of a u-shaped
duodenum(the first part of the small intestine)
the jejunum & the much coiled ileum. In man the
small intestine is about sis meters long. The lining
of the small intestine contains glands which
secrete digestive enzymes.

14. Pancreas
The pancreas is a gland lying in the loop of the
duodenum. It is connected to the duodenum by
means of the pancreatic duct. The bile duct joins
the pancreatic duct just before the latter opens
into the duodenum. The pancreas produces
pancreatic juice which contains digestive
enzymes.the pancreas also secretes the hormone
insuline which plays an important part in the control
of the blood sugar level in the body & utilization of
carbohydrates.

15. Pancreas

16. Large Intestine
 The large intestine is shorter but much broader than
the small intestine. The small intestine opens into the
large intestine at the right side of the abdominal cavity.
At the junction between the small intestine and the
ascending the colon is small sac, the caecum and the
blindly ending appendix.It is about 1.5 meters long.

17. Liver
 The liver is the largest gland in the body. It is dark red
and made up of 5 lopes 3 on the right and 2 on the left.
The liver secrete bile an alkaline greenish-yellow liquid
containing bile salts and bile pigments it does not
contain enzyme
Bile is temporarily stored in the gall bladder . The gall
bladder is a greenish-yellow liquid bag attached to the
liver. When the gall bladder r contracts the bile flows
into the duodenum via the bile duct.

18. Absorbtion
 Active transport plays an important role in the
absorption of the digested products , especially
glucose, amino acids and mineral salts glycerol is soluble
in water and it diffuses into the epithelium. In the
epithelium the soaps and glycerol recombine to form
minute fat globules which are absorbed by the
lymphatic capillaries. Water and mineral salts are also
absorbed by the large intestine. The undigested
material is temporarily stored in rectum . the removal of
undigested material is called egestion

19. Assimilation
 The transport & utilization of absorbed foods is
known as Assimilation.

20. The End