The document summarizes the key components and functions of the human digestive system. It describes how the digestive system breaks down food through mechanical and chemical processes across its main organs, including the mouth, esophagus, stomach, small intestine, large intestine, liver, pancreas, and gallbladder. Nutrients are absorbed through the small intestine walls and transported through the bloodstream, while waste is eliminated through the large intestine and anus.

1. By:
Dilip Kumar Mahto
Virbhusan Sonar
Anand Peters

2. INTRODUCTION
 The digestive system is used
for breaking down foods into
nutrients which then pass into
the circulatory system and
are taken to where they are
needed in the body and
remained matter are thrown
out of the body.

3. PHASES OF DIGESTIVE SYSTEM
 Ingestion
 Occurs when material enters
via the mouth
 Mechanical Processing
 Crushing / Shearing – makes
material easier to move
through the tract
 Digestion
 Chemical breakdown of food
into small organic compounds
for absorption
 Secretion
 Release of water acids, buffers,
enzymes & salts by epithelium
of GI tract and glandular organs
 Absorption
 Movement of organic
substrates, electrolytes,
vitamins & water across
digestive epithelium
 Excretion
 Removal of waste products
from body fluids

4. COMPONENTS
 Mouth
 Pharynx
 Esophagus
 Stomach
 Small Intestine
 Large Intestine
 Rectum
 Anus

5. MOUTH
 Begins when food enters
the mouth.
 It is physically broken
down by the teeth.
 It is begun to be
chemically broken down
by amylase, an enzyme
in saliva that breaks
down carbohydrates.

6. PHARYNX
 The tongue moves the food
around until it forms a ball
called a bolus.
 The bolus is passed to the
pharynx (throat) and the
epiglottis makes sure the
bolus passes into the
esophagus and not down the
windpipe!

7. ESOPHAGUS
 Approximately 10” long
 Functions include:
1. Secrete mucus
2. Moves food from the
throat to the stomach
using muscle
movement called
peristalsis

8. PERISTALSIS
 The bolus passes down
the esophagus by
peristalsis.
 Peristalsis is a wave of
muscular contractions
that push the bolus
down towards the
stomach.

9. STOMACH
 J-shaped muscular bag that stores the
food you eat, breaks it down into tiny
pieces.
 Mixes food with digestive juices that
contain enzymes to break down
proteins and lipids.
 Acid in the stomach kills bacteria.
 Food found in the stomach is called
chyme.
9

10. SMALL INTESTINE
 Small intestines are roughly 7 meters
long
 It has three parts –
1. Duodenum
2. Jejunum
3. Ileum
10

11. 1. DUODENUM
 Bile, produced in the
liver but stored in the
gall bladder, enters
through the bile duct.
It breaks down fats.
 The pancreas
secretes pancreatic
juice to reduce the
acidity of the chyme.

12. 2. JEJUNUM
 The jejunum is
where the majority of
absorption takes
place.
 It has tiny fingerlike
projections called
villi lining , which
increase the surface
area for absorbing
nutrients.

13. 3. ILEUM
The last portion of the
small intestine is the
ileum, which has fewer
villi and basically
compacts the leftovers
to pass through the
caecum into the large
intestine.

14.  Nutrients from the food pass into
the bloodstream through the small
intestine walls.
 Absorbs:
 80% ingested water
 Vitamins
 Minerals
 Carbohydrates
 Proteins
 Lipids
• Secretes digestive enzymes
14

16. LARGE INTESTINE
 The large intestine (or
colon) is used to
absorb water from the
waste material
leftover and to
produce vitamin K
and some B vitamins
using the helpful
bacteria that live here.

17. It is 5 feet long.
It has three parts…
1. Ascending Colon
2. Transverse Colon
3. Descending Colon

18.  All leftover waste is
compacted and
stored at the end of
the large intestine
called the rectum.
 When full, the anal
sphincter loosens and
the waste called
feces, passes out of
the body through the
anus.

19. LIVER

20. LIVER FUNCTION
The Physiology of the Liver
1. Metabolic regulation
2. Hematological regulation
3. Bile production

21. PANCREAS
 Lies posterior to stomach
 From duodenum toward
spleen
 Is bound to posterior wall of
abdominal cavity
 Is wrapped in thin,
connective tissue capsule
Functions of the Pancreas
1. Endocrine cells of the
pancreatic islets:
 Secrete insulin and
glucagon into bloodstream
2. Exocrine cells:
 Acinar cells and epithelial
cells of duct system
secrete pancreatic juice

22. GALL BLADDER
 Storage tank for bile (a greenish-yellow
liquid) that helps your body break down and
use fats
 Located under your liver
 Shaped like a pear
Gall Bladder

23. TONGUE
The tongue is fleshy,
movable, muscular organ,
attached in most
vertebrates to the floor of
the mouth, that is the
principal organ of taste,
an aid in chewing and
swallowing, and, in
humans, an important
organ of speech .

24.  derived from 1st-4th branchial arches
 manipulates food for chewing and swallowing
 contains no bony supports for the muscles
 the extrinsic muscles of the tongue anchor the
tongue firmly to surrounding bones and prevent the
mythical possibility of 'swallowing' the tongue
 sensitive and kept moist by saliva, and is richly
supplied with nerves and blood vessels to help it
move
PHYSIOLOGY

25. ANATOMY
 made mainly of skeletal
muscle
 dorsum
 oral part (anterior two-
thirds of the tongue) that
lies mostly in the mouth
 pharyngeal part
(posterior third of the
tongue), which faces
backward to the
oropharynx
 separated by a V-shaped
groove, which marks the
sulcus terminalis

26. PAPPILAE
 The oral part of the tongue is covered with small
bumpy projections called papillae. There are four
types of papillae:
 filiform (thread-shape)
 fungiform (mushroom-shape)
 circumvallate (ringed-circle)
 foliate (leaf-shape)
 All papillae except the filiform
have taste buds on their surface