DIGESTIVE SYSTEM

1. PANCREAS
Vigneswaran Ganesan M.sc.,
Senior Lecturer
Department of Biochemistry

3. PANCREAS
dual organ
having two functions
FUNCTIONAL ANATOMY OF
EXOCRINE PART OF
PANCREAS
 Structure resembles salivary
gland
 Made up of acini or alveoli
 Acinus – has a single layer
of acinar cells with a lumen
in the center.
 The acinar cells contain
zymogen granules, which
possess digestive enzymes.
FUNCTIONS
Endocrine function
- Production of
hormones
Exocrine function
- Secretion of
digestive juice
(Pancreatic juice)

5.  Small duct arises from the lumen of the alveolus
 Some of these ducts from neighboring alveoli unite to form intralobular duct.
All intralobular duct.
joins common bile duct to
form ampulla of vater.
Which opens in the duodenum
main pancreatic duct
WIRSUNG DUCT
unite to form
• Accessory duct (duct of Santorini)
Exists in some persons
Also opens into duodenum, proximal to the
opening of ampulla of vater.

7.  Pancreas is supplied by
both sympathetic and
parasympathetic fibers.
 Sympathetic fibers are
supplied through
splanchnic nerve
 Parasympathetic fibers
are supplied through
vagus nerve.

8.  Volume : 500 to 800 mL/day
 Reaction : Highly alkaline with pH of 8 to 8.3
 Specific gravity : 1.010 to 1.018

10. It plays an important role:
 in digestion of lipids proteins and carbohydrates,
 in metabolism since it produces insulin and other
hormones.
 in neutralizing the pH to become suitable for the
action of the pancreatic digestive enzymes.

11. DIGESTIVE FUNCTIONS
Proteolytic enzymes – secreted as inactive
precursors
trypsinoge
n
trypsin
enterokinas
e
chymotrypsinogen
procarboxypeptidase
chymotrypsin
carboxypeptidas
e
Single polypeptide
Mw 25000
229 aas
polypeptide
Mw 25700
246 aas

14. CA- CARBONIC
ANHYDRASE
H2CO3 - CARBONIC ACID
 CO2 diffuses to the ductule
cells from blood
 CO2 combines with H2O in
presence of CA to form
H2CO3
 H2CO3 dissociate into
HCO3
- and H+ .
 The HCO3
- is actively
transported into the lumen.

15.  The H+ formed
are exchanged for
Na+ ions by active
transport through
blood , which will
diffuse or actively
be transported to
the lumen

16.  The movement of
HCO3
- and Na+ ions
to the lumen causes
an osmotic gradient
causes water to
move from blood to
ductule cells of the
pancreas producing
eventually the
HCO3
- solution

17.  Secretion of pancreatic juice is stimulated by:
 Secretin:
◦ Occurs in response to duodenal pH < 4.5.
◦ Stimulates production of HC03
- by pancreas.
◦ Stimulates the liver to secrete HC03
- into the bile.
 CCK:
◦ Occurs in response to fat and protein content of chyme in duodenum.
◦ Stimulates the production of pancreatic enzymes.
◦ Enhances secretin. Relaxation of the sphincter of Oddi.

19. Pancreatitis (inflammation in pancreatic
acini)
Acute and chronic- Types
Acute- develops rapidly ,Chronic-
progressive inflammatory disease with
severe structural changes and loss of
functions
 Causes of pancreatitis
 Long-time consumption of low
alcohol.
 Congenital abnormalities of
pancreatic duct.
 Malnutrition (poor nutrition; mal =
bad).
 Heavy alcohol intake.
 Gallstones
 Features of pancreatitis
 Absence of pancreatic enzymes.
 Steatorrhea.
 Severe abdominal pain.
 Nausea and vomiting.
 Loss of appetite and weight.
 Fever.
 Shock.

20. Steatorrhea is the formation of bulky, foul
smelling, frothy and clay colored stools with
large quantity of undigested fat because of
impaired digestion and absorption of fat.
Causes of Steatorrhea
1. Lack of pancreatic lipase.
2. Liver disease affecting secretion of bile.
3. Atrophy of intestinal villi.

22. a. Alkaline PH
b. Enterokinase
c. Bile salts
d. Chloride ion

23. a. Alkaline PH
b. Enterokinase
c. Bile salts
d. Chloride ion

24. a.Enterokinase
b.Alkaline PH
c.Trypsin
d.Bile salts

25. a.Enterokinase
b.Alkaline PH
c.Trypsin
d.Bile salts

26. a. Gastrin
b. Bile salts
c. Enterokinase
d. Chloride ions

27. a. Gastrin
b. Bile salts
c. Enterokinase
d. Chloride ions

28. a. Its pH is about 8
b. Has high HCO₃⁻ content
c. It’s secretion is primarily under neural
control
d. Contains digestive enzymes

29. a. Its pH is about 8
b. Has high HCO₃⁻ content
c. It’s secretion is primarily under neural control
d. Contains digestive enzymes

30. a. Bile salts
b. Trypsin
c. Cl ⁻ ions
d. Enterokinase

31. a. Bile salts
b. Trypsin
c. Cl ⁻ ions
d. Enterokinase

32. a. 0.6 liter
b. 1.5 liter
c. 3 liter
d. 2.5 liter

33. a. 0.6 liter
b. 1.5 liter
c. 3 liter
d. 2.5 liter

34. a. Sympathetic stimulation inhibits pancreatic HCO₃⁻
secretion
b. The cephalic phase accounts for about 20 % of
secretion after meal
c. Pancreatic HCO3 depresses further release of
secretin
d. Contains enzymes which digest polysaccharides to

35. a. Sympathetic stimulation inhibits pancreatic HCO₃⁻
secretion
b. The cephalic phase accounts for about 20 % of
secretion after meal
c. Pancreatic HCO3 depresses further release of
secretin
d. Contains enzymes which digest polysaccharides to

36. a. Somatostatin
b. Glucagon
c. Acid in the duodenum
d. Sympathetic stimulation.

37. a. Somatostatin
b. Glucagon
c. Acid in the duodenum
d. Sympathetic stimulation.

38. a. Maldigestion
b. Malabsorption
c. Dehydration
d. Alkalosis

39. a. Maldigestion
b. Malabsorption
c. Dehydration
d. Alkalosis