The digestive system breaks down food into nutrients that the body can use. It begins with the mouth and ends with the anus. Major organs include the mouth, esophagus, stomach, small intestine, large intestine, liver, gallbladder and pancreas. Food is ingested, digested, absorbed in the small intestine, and waste is excreted. Digestion involves breaking down food into smaller molecules like amino acids and monosaccharides using enzymes from the saliva, stomach acid, bile, and pancreatic juice. The small intestine absorbs nutrients into the bloodstream through villi while the large intestine absorbs water before excreting waste.

1. DIGESTIVE SYSTEM
Digestive system is uniquely designed to turn the food you eat into nutrients,
which the body uses for energy, growth and cell repair.
The digestive system is described as opening toning. That is open with
mouth an endwith Anus
The organs of digestive system are:
Mouth
Pharynx
Esophagus
Liver
Stomach
Gall bladder
Pancreas
Small Intestine
Rectum
Anus

2. Accessory organs are :
1.Salivary glands
2.Liver
3.Gall bladder
4.pancreas
Food, which we take, cannot be absorbed directly in our body. First it gets
converted in to simple forms so that it becomes easily absorbable in to blood. The
food has to undergo number of chemical changes in (GIT) Gastrointestinal tract.
In digestive system composed of four steps:
1. Ingestion: It is a process of taking food to the Alimentary canal.
2. Digestion: It is a process of breaking down the complex food material.
3. Absorption: It is take place in wall of the Small intestine, which contain blood
Absorption takes place by Villi (wave or finger likevessels and lymph vessels.
structure).
4. Execration: It is undigested food material is eliminated by the bowel action
(feces)..

3. Mouth: bones and Muscles form Mouth.
The upper jaw is called maxilla
The Lower jaw is called mandible
The roof of mouth is called palate
Hard
(Anterior)
Soft
(Posterior)
Uvula is a curved fold of Muscles lined by the mucous membrane hanging down
at the border of the soft Palate.
Function: Producing sound and speech.

4. The Floor of mouth is called as Tongue. It is attach to the lower jaw.
Function: It moves food around during mastication (chewing) and deglutition
(swallowing) Food sends it to back.
The Tongue has TASTE BUDS distributed all over its surface when food enters in
Mouth the impulses from this nerve ending indicates that the food is
expectable or not.
Teeth: The mouth has 8th Pairs of teeth in one jaw.
1. Two pair of Incisor
2. One pair of Canine
3. Two pair of Premolar
4. Three pair of Molar
Function: Breaking up the solid part in to smaller part and at the same time
Saliva secreted by three pairs of salivary glands.
1. Parotid gland
2. Submandibular gland
3. Sublingual gland (bottom of the tongue)

5. Pharynx:
Pharynx is a muscular tube about five inches long lined with a mucus
membrane. The pharynx is a common pathway for air travelling from the
nose to trachea and food travelling from the oral cavity enters in the
Pharynx.
Esophagus: Esophagus is a muscular tube about 9 to 10 inches long. It has
two ends called upper and lower ends it is covered by circular Muscles
called Sphincter.
The upper sphincter is called cricopharyngeal sphincter.
The Lower sphincter is called esophageal sphincter.
Rhythmic contraction and relaxation of muscles in the wall of the
esophagus is called Peristalsis. The Peristalsis helpful for propel the food
towards the stomach.
Stomach: Stomach is a muscular bag and it is "J" shape organ. Stomach is
composed of three portions.

6. Middle part-
Body
Upper Part-
Fundus
Lower part-
Pylorus
Stomach
The stomach controlled by two sphincters. The upper part is called Cardiac sphincter.
The Lower part is called pyloric sphincter.
After the sufficient digestion in pylorus part these are special type of mucus
membrane is known as Rugae (small fold like structure) it is also called as Gastric
Gland. It produce Gastric juice is increased considerably after meal.

7. Three main components of gastric juice
1.Pepsin 2.Renin 3.HCL (Hydrochloric acid )
AMINO
ACID
FATTY
ACID
GLUCOSE
PROTEIN
SUGAR
FATE
Function:
1. Stomach secretes gastric juice for digest the food and its acidic nature kills the
bacteria.
2. Stomach is preparing the food chemically and mechanically so small intestine
receivesthe food for further digestion.
(Food leaves in the stomach in 1 to 4 hours or longer depending upon the
amount and type of food eaten.)
Example :

8. Small Intestine:
Small intestine has three parts
 Upper Part is called duodenum it receive food from stomach, bile
from liver and gallbladder and Pancreatic juice from pancreas.
 Middle Part is called Jejunum is chimicet with the third part of small
Intestine.
 Third Part is called Ileum connects with first part of large intestine by
valve is called Ileocecal Valve.
Small Intestine lined with special type of structure is called Villi.
The Villi is very tiny and microscopic blood vessels like structure is
millions in number. The Villi absorb the digested nutrient in to the blood
stream and lymph vessels.

9. Large intestine:
The large intestine is extended from the end of the Ileum to the Anus.The large
intestine divided in to four Parts.
1. Cecum: In the cecum at the right side the Veriform (westigion organ) like
structure is called Appendix.
2. Colon: It is about five feet long it has three divisions
1.Asendingcolon
2.Transverse (Horizontal)
3.Descending colon
In between the ascending colon and transverse colon there is a band or turning
which is called as Hepatic flexure.
In between the transverse colon and descending colon there is a band or turning
which is called as splenic flexure.
3. Sigmoid colon: It is a Zigzag like structure.
4. Rectum: Terminate (end) in the lower opening of the GIT (Gastro intestinal
track) that is Anus.

10. Function of large Intestine:
Absorption of water within the waste material and expel the solid stool
(feces). It store waste product until they can be release Diarrhea, watery stool
can result from lack of absorption of the water through the wall of the large
Intestine.
Accessory organ of Digestive system
1. Salivary gland
2. Liver
3. Gall bladder
4. Pancreas
1. Salivary gland: Three pairs
(a) Parotid gland
(b) Submandibular gland
(c) Sublingual gland
Three Pairs of salivary glands surround the oral cavity these exocrine glands
produce a fluid called Saliva that contains important digestive enzyme.
Narrow ducts carry the saliva in to the oral cavity.

11. Liver:
Liver, gall bladder and pancreas play crucial roles in the proper digestion
and absorption of nutrients. Liver manufactures yellowish brown
sometimes greenish fluid called Bile
Bile
Function of Liver:
1. Destruction of old erythrocytes and release a Bilirubin
2. Keeping the amount of glucose (sugar) in the blood at a normal level
it store as a glycogen
Whenever body demands glucose, glycogen converts in to
glucose.
3. Manufacture of some blood proteins particularly those necessary for
blood clotting.
4. The bile helps in digestion of fat this process is called Emulsification.
5. It helps to remove the toxic substance

12. Duct
gland
Ductless
gland
Small
pathway
Exocrine
Duct
Endocri-
ne
Pancreas:
Pancreas is both exocrine and an endocrine organ
As an Exocrine it secretes Pancreatic juice filled with enzyme Amaylase
and lipase) to digest food.
This enzyme passes in to duodenum through the pancreatic duct. As an
Endocrine Part of pancreas consist
"Islets of Langerhans" The Islets of Langerhans has and cell

13. Both of these hormones play a role in the proper metabolism of sugars and
starch cell and cell have no duct and it is mixed with blood.
Islets of
Langerhans
Secret
Insulin
Glycogen