The digestive system begins at the mouth and is approximately 30 feet long. It breaks down food, absorbs nutrients into the bloodstream, and eliminates waste. The main organs are the mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus. Food is ingested, moved through peristalsis, broken down mechanically and chemically, absorbed, and waste is eliminated as feces through the anus. Accessory organs like the liver, gallbladder and pancreas produce enzymes and bile to aid chemical digestion in the small intestine.

1. ANATOMY AND
PHYSIOLOGY
THE DIGESTIVE SYSTEM

2. What is the Digestive System?
 The digestive system is
a continuous tube that
begins at the mouth and
ends at the anus.
 It measures about 30
ft. long in the average
adult, it is known as the
alimentary canal or the
gastrointestinal tract.

3. 3 Functions of the Digestive System
1. Breaking of the foods into nutrients,
2. Absorbing nutrients into the
bloodstream, and
3. Eliminating the indigestive parts
of food from the body.

4. The digestive system is consists of the
GI tract or alimentary canal and the
accessory organ of the digestion.
GI Tract
1. Mouth
2. Throat and
Esophagus
3. Stomach
4.Small Intestine
5. Large Intesine
6. Rectum and Anus
Accessory organs of
digestion
1. Salivary Glands
2. Liver
3. Gallbladder
4. Pancreas

5. 6 Process of Digestion
1.Ingestion
- entry of food into the
alimentary canal through
the mouth.
2. Propulsion
- the movement of food
through the digestive tract.
ex. swallowing
3. Mechanical Digestion
- physical process that
does not change the
chemical matter of the
food.
ex. Chewing or
Mastication

6. Continued...
4. Chemical Digestion
- aided by the secretions
of enzymes.
5. Absorption
- nutrients are absorbed
from the lumen of the
alimentary canal to the
bloodstream.
6.Defecation
- undigested materials
are removed from the
body as feces.

7. 1. Mouth/ Oral Cavity – this is where the
digestion begins.
 1. The Teeth – breaks
the food apart by
chewing....
mastication.
 3. The Tongue – it is a
muscle covered with
mucous membrane
the helps push the
bolus into the throat.
 2. Salivary Glands –
which secretes the
chemical called
saliva. Which mix
with the food to form
a bolus.

8. 2. The Esophagus
- it is a collapsible tube that connects the
pharynx and the stomach.
- it is atleast 10 inches in length, and
- it is divided into 3 segments, the CERVICAL, THORACIC
AND THE ABDOMINAL.
- it lubricates the food and moves
it to the stomach by peristalsis.

9. 3. The Stomach
- is an organ with strong
muscular walls.
-it is divided into 5
parts, Cardia, Fundus,
the Body, Antrum, and
the Pylorus

10. Continued...
- it holds the food and mixing
with Hydrochloric Acid and
other gastrtic juices:
1. Pepsin, 2. Intrinsic Factor, 3.
Lipase; that continue to break
down the food to a semiliquid
state called chyme.
- chymes passes through the pyloric sphincter
valve at the bottom of the stomach
into the small intestine.

11. 4. The Small Intestine
- considered to be the work
force of the digestive system.
- it is about 21 ft. long and 1 inch
in diameter, extending from the
pyloric spinchter valve to the
large intestine
- it will continue to break
down foods with the help of
enzymes, released by the
pancreas and bile released
from the liver.
- it absorbs most of
the nutrients of the
food.

12. 3 Segments of the Small Intestine
1. Duodenum
- foot- long section just beyond the
stomach.
2.
Jejunum
- is the next 8 feet.
3.
Ileum
Is the remaining 12 feet.
- receives food from the stomach
via pyloric sphincter.
Jejunum and Ileum' s entire
surface area are covered in
villi to aid absorptions

13. Pancreas
- among its other function,
the pancreas helps
digestion by producing
enzymes and sending them
to the duodenum via the
pancreatic duct, this
enzymes break down
proteins, fats and
carbohydrates,

14. The Liver
- one of the many organs that
has many functions.
- the primary contribution to the
digestion process is the
production of bile or gall which
drains into the duodenum thru
the hepatic duct. While some
bile is stored in the gallbladder,
where it becomes more
concentrated, increasing its
potency and intensifying effect.

15. The Gallbladder
- serves as storage of bile or gall
- when the fat- containing chyme
leaves the stomach, the
gallbladder contracts and
discharges bile through the
cystic duct and common bile duct
and into the duodenum

16. 5. The Large Intestine
- 5 inches long and 2 ½ inches in
diameter
Dauhin's Valve – divide the small and
large intestines. Like other valves, its
action is to relax and contracts
allowing matters to pass through and
prevent backflow,
- Subdivided into 4 sections.
Cecum, Ascending Colon, Transverse Colon, Descending
Colon and Sigmoid Colon

17. Continued...
- large intestine has no villis because most of the nutrients
is already absorbed by the small intestines.
- however, large intestine has an estimated 100 billion
bacteria inside, these bacterias are important in many task
such as the production of vitamins and the decomposition of
fiber for the body energy production.
- Its main function is to absorb the remaining water in
the chyme; furthermore adding mucous causing the
food to become firmer and turn into stool.

18. 6. The Rectum and Anus
The rectum is where
feces are stored
until they leave the
digestive system,
through the anus as
a bowel movement.
As the rectal walls expand
with waste material,
receptors from the nervous
system stimulate the desire
to defecate. For defecation
or egestion, we consciously
relax the external anal
sphincter muscle to expel
the waste through the anus.

19. ...and this is where our journey of the digestive
system ends.

20. Organs Movement Events Particles
Breakdown
Mouth/ Oral
Cavity
Swallowing Chewing and
mixing of saliva
forming a bolus.
Carbohydrates
Esophagus Peristalsis
Stomach Mixes food with
digestive juices.
Proteins
Small Intestine Peristalsis Breakdown of
most nutrients
aided by the
Liver, Pancreas,
Gallbladder
Proteins,
Carbohydrates,
Fats
Large Intestine Peristalsis Absorbs water. Water
Rectum Storage of feces
Anus