The document describes the roles of the stomach, pancreas, liver, gallbladder, and sections of the small intestine in digesting nutrients and absorbing them. It explains that the stomach contains enzymes like pepsin that break down proteins and the pancreas and intestinal glands produce enzymes that further break down carbohydrates, proteins, and lipids in the small intestine. Finally, it states that the liver produces bile which is stored in the gallbladder and released to emulsify fats during digestion in the small intestine.

2. 1. Describe the functions of the stomach, duodenum,
pancreas, gall bladder, liver, ileum, jejunum in relation
to physical digestion, chemical digestion, absorption of
nutrients and water.
2. State the function of proteases pepsin and rennin on
proteins and list the end products of protein digestion
in the stomach.
3. List the digestive enzymes produced by the intestinal
glands and pancreas.
4. Describe the function of bile in the emulsification of
fats.
Objectives

3. Stomach
Peristalsis in the stomach
wall churns and break up
the food
Peristalsis also mix food
with the gastric juice

4. Gastric gland secrete
gastric juices into the
stomach
Hydrochloric
acid
Proteases
•Pepsin
•Rennin

5. Hydrochloric acid
•Kills most bacteria
taken in with food
•Provides an acidic
medium suitable for
the action of gastric
enzymes.

6. Stomach
Hydrochloric
acid
Pepsinogen Pepsin
(active enzyme)
Prorennin Rennin
(active enzyme)

7. Why is pepsinogen produced
instead of pepsin?
To prevent pepsin
from digesting the
stomach walls

8. Protein Digestion
Proteins Polypeptides
Pepsin
Soluble Insoluble
milk proteins milk proteins
Rennin
Insoluble Polypeptides
milk proteins
Pepsin

9. Why is there no digestion of
starch in the stomach?
The acidic environment in the stomach due to
the presence of hydrochloric acid. Salivary
amylase works best in alkaline pH. Thus no
starch is digested in the stomach.
Question Time!

10. Stomach
After mixing and enzyme
digestion, food becomes
a nutrient-rich broth : Chyme

12. Liver
Pancreas
Gall
bladder
Duodenum
of Small
intestine

13. Liver
Pancreas
Gall
bladder
Duodenum
of Small
intestine

14. Secrete Intestinal juice
Maltase Sucrase
Lactase Erepsin
Intestinal
lipase
Intestinal Gland

15. Secrete Pancreatic Juice:
• Pancreatic amylase,
• Pancreatic lipase
• Trypsinogen
trypsin
(active enzyme)
Pancreas
enterokinase

16. Region of
Digestion
Source Enzyme Action
MOUTH Salivary glands Salivary amylase Starch Maltose
STOMACH Gastric glands
Pepsin
Rennin
Protein Polypeptide
Soluble Insoluble
milk proteins milk proteins
SMALL
INTESTINE
Pancreas
Intestinal
glands
Pancreatic
Amylase
Trypsinogen
trypsin
Pancreatic Lipase
Maltase
Erepsin
Lipase
Starch Maltose
Protein Polypeptides
Fats Fatty acids+ glycerol
Maltose Glucose
Polypeptides Amino acids
Fats Fatty acids+ glycerol

17. Liver produces bile
which is an enzyme that
breaks down fats
The bile salts which emulsify
fats into tiny fat droplets is
stored in the liver
Four friends were
discussing about the role
of the gall bladder, liver
and the function of bile.
Who do you agree with the
most? Explain why others
are not correct.
Bile which emulsify
fats is produced from
the liver and stored in
the gall bladder
Gall bladder
produces bile
which breaks
down fats
John
Daniel
Mary Bella

18. Liver cells secrete bile
containing bile salts and
bile pigment
Bile = bile salts + bile
pigment
Bile is temporarily stored
in the gall bladder
Bile flows into the
duodenum via the bile
duct

19. Bile salts emulsify the fats by
reducing the attractive forces
between the fat molecules
Physically breaks-up the fat
molecules
Bile Salts
Tiny fat
droplets
Increase surface area to
volume ratio – speed up
digestion by lipase.
Bile salts

20. 1. Describe the functions of the stomach, duodenum,
pancreas, gall bladder, liver, ileum, jejunum in relation
to physical digestion, chemical digestion, absorption of
nutrients and water.
2. State the function of proteases pepsin and rennin on
proteins and list the end products of protein digestion
in the stomach.
3. List the digestive enzymes produced by the intestinal
glands and pancreas.
4. Describe the function of bile in the emulsification of
fats.
Let’s Review

21. Due to cancer of the stomach, the
entire stomach of Patient A have
being surgically removed.
As the doctor of Patient A, you are to
provide information on the effect on
the lifestyle and digestive function
upon removing the stomach.

22. • Stomach is the site of initial protein digestion.
Removal of stomach will cause protein digestion
to be greatly affected;
• Patient A can rely only on the small intestine for
protein digestion, rate of protein digestion will be
lowered.
• No HCl, prone to food infection by bacteria.
• Need to reduce protein intake to avoid congesting
the small intestine.