Digestive system

2. Contents of the presentation :-
Introduction
The Anatomy
of digestive
system
Mouth Salivary gland pharynx
Esophagus Stomach Small intestine Large intestine Large Intestine
Appendix Rectum Anus Liver Gall Bladder
Pancreas
The
Conclusion

3. Introduction
What is Human digestive
system ?
-Is consists of the gastrointestinal
tract plus the accessory organs of
digestion (the tongue, salivary
glands, pancreas, liver,
and gallbladder). Digestion involves the
breakdown of food into smaller and
smaller components, until they can be
absorbed and assimilated into the body.
The process of digestion has three
stages: the cephalic phase, the gastric
.
phase, and the intestinal phase

4. The Anatomy of the Digestive System
The digestive system consists of various
organs, including the mouth, esophagus,
stomach, small intestine, large intestine, liver,
gallbladder, and pancreas.
-These organs work in harmony to break
down food, extract
.
nutrients,
.
and eliminate
waste
- Digestive system consists of 2 major parts:-
1 - Major organs :
Mouth-Esophagus-Stomach-small intestine -
large intestine.
2- Accessory organs:
Liver - Gall bladder - Pancreas .

5. Mouth and Salivary Glands
The mouth :-
pH: 7
- The first part of the digestive system
- the entry point of food.
Structures in the mouth that aids digestion
* Teeth cut, tear, crush and grind food.
*Salivary glands produce and secrete
saliva into the oral cavity .
-
:
salvia
moistens the food
contains enzymes (ptyalin or salivary amylase)
begins digestion of starch into smaller
polysaccharides.
Function:
-Mechanical digestion.
- increasing surface area for faster chemical
digestion.

6. The Esophagus
-After swallowing, food
travels down the muscular
tube
.
known as the
esophagus
-Peristalsis, rhythmic muscle
contractions, propels
food from the esophagus to
.
the stomach
-The esophagus plays a crucial
role in transporting food to
the stomach efficiently.

7. Stomach and Gastric Juices
.
-J-shaped muscular sac
.
- Has inner folds (rugae)
- Increasing surface area of the stomach.
Functions :
-
-The stomach acts as a temporary storage reservoir for
food.
- Stomach performs mechanical digestion By churning the
bolus and mixing it with the gastric juices secreted by the
lining of the stomach.
:
*GASTRIC JUICES
.
- HCl, salts, enzymes, water and mucus
-HCL helps break down of food and kills bacteria that
came along with the food.
Mucus prevents the stomach from digesting itself.
-
-Pepsin responsible for hydrolyzes proteins to yield
polypeptides.

8. Small Intestine
-responsible for the complete
digestion of all macromolecules
and the absorption of their
component molecules.
-
-It is divided into three parts: -
the duodenum, jejunum, and ileum
-Digestive enzymes from the
pancreas and bile from the liver
and gallbladder facilitate the
breakdown of carbohydrates,
.
proteins, and fats

9. Nutrient Absorption in the Small Intestine
-The small intestine contains
microscopic finger-like
projections called villi, which
tremendously increase surface
.
area for nutrient absorption
-Nutrients, including glucose,
amino acids, and fatty acids, are
absorbed into the bloodstream
and transported to various cells
and tissues for energy.

10. Large Intestine
The large intestine is composed of several very distinctive
parts:
1-Cecum:
first section of your large intestine
looks like a pouch,
two inches long.
* ROLE
-taking in digested liquid from the ileum(small intestine)
& passes it on to the colon.
2- Colon:. The colon consists of four parts:
Ascending colon - Transverse colon - Descending colon -
Sigmoid colon
*Function:
the principal place for water reabsorption,
absorbs salts when needed.
3- Rectum :
The final section - measures from 1 to 1.6 inches (or 2.5 to
4 cm) - Leftover waste collects there - expanding the
.
Rectum - emptied through anus

11. FUNCTION OF THE LARGE INTESTINE
1. Absorb Water
-
One of the primary functions is to absorb water - prepare the waste as
a solid stool that will be expelled from the body.
2. Absorb Vitamin
- beneficial bacteria - role in breaking down undigested sugars and fibers
into fatty acids. - produce many vitamins, of which are Vitamin K and
Biotin that are absorbed back into the body.
3. Reduce Acidity
The fatty acids cause acidic environment - The LI produces alkaline
solutions - reduce the acidity and balance the pH in the LI .
4.Protect from Infections
The mucous lining of the large intestine acts as a protective layer prevents
harmful bacteria from being reabsorbed into the body.
5. Produce Antibodies
also produces antibodies help to boost immunity. It is believed that the
appendix may have been a major producer of antibodies at some point in
the evolutionary process .

12. Liver
*Liver
largest of these organs ,mass of
about 1.5 kg.
.
,liver produces bile
* bile
-greenish yellow pigment made
up bile
.
pigments and bile salts
- it breaks down old red blood
cells.

13. Gallbladder
a storage sac. , The bile is secreted into
it , The bile is stored here.
HOW IT WORKS ?
*food containing fat enters the
digestive tract :
-salts are secreted into the
small intestine to digest fats.
- The bile emulsifies fats in partly
.
digested food
.
- thereby assisting their absorption

14. Pancreas
-The pancreas, both an endocrine and
exocrine gland, produces insulin (endocrine
function) and digestive enzymes (exocrine
function) .
-The pancreas secretes a number of different
enzymes into the small intestine ,These
enzymes, including amylase, protease, and
lipase.
- Role is to digest carbohydrates lipids &
proteins completely.
.
- It also secretes bicarbonate ions
Role :
-neutralize the HCl from the stomach change
the pH of the small intestine to a pH of 8.
-The pancreas will secrete about 1.0 L. of
pancreatic fluids per day.

15. Waste Elimination
-Waste products, such as
indigestible food and dead cells,
are eliminated from the body
through the process of
defecation.
-The colon absorbs water from
fecal matter, forming solid waste,
while the rectum and anus
regulate the excretion process.

16. The Conclusion
-The digestive system is a marvel
of engineering, showcasing the
intricate processes that allow our
bodies to extract nutrients and
eliminate waste.
-Understanding the functionality
of our digestive system empowers
us to make informed choices
.
regarding diet and overall health
-Let us embrace the significance
of this remarkable system and
nurture our bodies accordingly.

17. We will now open the floor for any questions you may
have about digestive system?