The pancreas is an organ that has both exocrine and endocrine functions. It produces pancreatic hormones like insulin, glucagon, and somatostatin that are secreted by different cell types and regulate metabolism. Insulin is produced by beta cells and stimulates glucose and lipid uptake in tissues, while glucagon from alpha cells causes the liver to release glucose. Diabetes occurs when there is inadequate insulin production or resistance, and is controlled through insulin injections or lifestyle changes.

1. Pancreatic Anatomy
• Gland with both exocrine and endocrine
functions
• 15-25 cm long
• 60-100 g
• Location: 2nd lumbar vertebral level
• Extends in an oblique, transverse position
• Parts of pancreas: head, neck, body and tail

2. Pancreas

3. Pancreatic Hormones, Insulin and Glucagon,
Regulate Metabolism

4. Production of Pancreatic Hormones by Three Cell
Types
 Alpha cells produce glucagon.
 Beta cells produce insulin.
 Delta cells produce somatostatin.

5. Pancreas Histology

6. Islet of Langerhans Cross-section
• Three cell types are
present, A (glucagon
secretion), B (Insulin
secretion) and D
(Somatostatin secretion)
• A and D cells are located
around the perimeter while
B cells are located in the
interior

7. Islets of Langerhan (Pancreatic Islets)

8. Pancreatic Hormones, Insulin and Glucagon,
Regulate Metabolism
Figure 22-8: Metabolism is controlled by insulin and glucagon

9. Structure of Insulin
• Insulin is a polypeptide hormone, composed
of two chains (A and B)
• BOTH chains are derived from proinsulin, a
prohormone.
• The two chains are joined by disulfide bonds.

11. Pancreatic Hormones, Insulin &
Glucagon Regulate Metabolism
Figure 22-8: Metabolism is controlled by insulin and glucagon

15. Insulin Stimulates Cellular Glucose Uptake
Liver
Skeletal Muscle
Adipocytes
Intestine & Pancreas
Insulin
Insulin
Insulin

16. Glucagon and Insulin

17. Action of Insulin on Adipose Tissue
• Stimulates glucose uptake
• Stimulates glycolysis
• Stimulates lipogenesis
• Inhibits lipolysis and ketogenesis

18. Actions of Glucagon on the Liver
• Stimulates glycogenolysis
• Stimulates gluconeogenesis
• Inhibits glycolysis
• Stimulates lipolysis and ketogenesis

22. Actions of Insulin on the Liver
• Stimulates glucose uptake
• Stimulates glycogenesis
• Stimulates glycolysis
• Stimulates HMP shunt activity
• Inhibits glycogenolysis
• Inhibits gluconeogenesis
• Stimulates lipogenesis
• Inhibits lipolysis
• Stimulates cholesterol synthesis
• Increases VLD lipoprotein
• Increases potassium and phosphate uptake

23. Actions of Insulin on Muscle
• Stimulates glucose uptake
• Stimulates glycogenesis
• Stimulates glycolysis
• Inhibits glycogenolysis
• Inhibits FFA uptake and oxidation
• Stimulates proteogenesis
• Inhibits proteolysis
• Stimulates uptake of potassium, phosphate and
magnesium
• Increases blood flow

24. GLUCAGON
Alpha cells
Hypoglycemia =
glucagon secretion
Actions
increased glycogenolysis
increased gluconeogenesis
Result = normoglycemia
hypoglycemia (<90mg%)
alpha cells secrete glucagon
liver cells:
increase glycogenolysis
increased gluconeogenesis
normoglycemia (>90mg%)
( -)
negative
feedback
increased blood glucose

25. INSULIN
Beta cells
Hyperglycemia =
insulin secretion
Actions
increased glucose uptake
increased glycogenesis
increased lipogenesis
hyperglycemia (<110mg%)
beta cells secrete insulin
increased glucose uptake into body cells
increase glycogenesis
(skeletal muscle, liver)
increased lipogenesis
normoglycemia (<110mg%)
( -)
negative
feedback
decreased blood glucose
Result = normoglycemia
Diabetes mellitus

26. Normal
LPL
Triglyceride
Lipolysis
Glycerol
Free fatty acids
Free fatty acids
Glucose
Synthesis
Insulin
Insulin

27. Triglyceride
LPL
Type 1 Diabetes Mellitus
LipolysisGlycerol
Free fatty acids
Free fatty acids
Glucose
Synthesis

28. Diabetes Mellitus
• This is a disease caused by elevated glucose levels
• 2 Types of diabetes:
Type I diabetes (10% of cases)
Type II diabetes (90% of cases)

29. Type I Diabetes (10% of cases)
•Develops suddenly, usually
before age 15
•Caused by inadequate
production of insulin because T
cell-mediated autoimmune
response destroys beta cells
•Controlled by insulin injections

30. Type II diabetes (90% of cases)
• Usually occurs after age 40 and in
obese individuals
• Insulin levels are normal or
elevated but there is either a
decrease in number of insulin
receptors or the cells cannot take it
up.
• Controlled by dietary changes and
regular exercise

31. • Glucose homeostasis
Figure 26.8
Insulin
Beta cells
of pancreas stimulated
to release insulin into
the blood
Body
cells
take up more
glucose
Blood glucose level
declines to a set point;
stimulus for insulin
release diminishes
Liver takes
up glucose
and stores it as
glycogen
High blood
glucose level
STIMULUS:
Rising blood glucose
level (e.g., after eating
a carbohydrate-rich
meal) Homeostasis: Normal blood glucose level
(about 90 mg/100 mL) STIMULUS:
Declining blood
glucose level
(e.g., after
skipping a meal)
Alpha
cells of
pancreas stimulated
to release glucagon
into the blood
Glucagon
Liver
breaks down
glycogen and
releases glucose
to the blood
Blood glucose level
rises to set point;
stimulus for glucagon
release diminishes

32. Insulin
I
I
I
Beta Cell
Dysfunction
Increased
SGO
Exxagerated lipolysis
Insulin Resistance
Decreased Glucose
Uptake
Type 2 diabetes: patophysiology
Pancreas

33. Insulin
I
I
I
Insulin
Secretion
Insulin Effects
FOOD
Pancreas
Restrain of
HGO Uptake of glucose
Storage In Fat Depots
Inhibition of Lipolysis