The document discusses the endocrine pancreas and its role in regulating blood glucose levels. It notes that the pancreas has both exocrine and endocrine functions. The endocrine pancreas contains four main cell types - alpha, beta, delta, and PP cells. Alpha cells secrete glucagon, which raises blood glucose levels. Beta cells secrete insulin, which lowers blood glucose levels. Delta cells secrete somatostatin, which regulates alpha and beta cell secretion. PP cells secrete pancreatic polypeptide, though its role is uncertain. Together, glucagon and insulin work to maintain glucose homeostasis and keep blood glucose levels within a normal range.

1. ENDOCRINE
PANCREAS

2. DIFFERENCE BETWEEN EXOCRINE AND
ENDOCRINE GLANDS
Secrete their essential product by way
of a duct to some environment external
to itself, either inside the body or on a
surface of the body.
EXAMPLES
• Salivary Glands
• Tear Glands
• Anal Glands
• Stomach Pit
Secrete their products, hormones,
directly into the blood rather than
through a duct.
EXAMPLES
• Pituitary Gland,
• Pineal Gland,
• Thyroid Gland,
• Adrenal Gland,
• Pancreas,
• Testes &Ovary, etc,.

3. • Glandular Organ
• Size: 6-9 inches
• Weight: 3 ounces (85 gm)
• Position: partially behind the stomach
• Color: Grayish-pink
• STRUCTURE
 Head concavity of
duodenum
 Body base if stomach
 Tail abutting the spleen
• HETEROCRINE GLAND
Exocrine Tissue Endocrine
Tissue
99% 1%

5. MICROSCOPIC ANATOMY

6. HORMONES OF ENDOCRINE PANCREAS
α alpha cells secrete glucagon (increase glucose in blood),
β beta cells secrete insulin (decrease glucose in blood),
Δ delta cells secrete somatostatin (regulates/stops α and β cells)
and
PP cells, or γ (gamma) cells, secrete pancreatic polypeptide

7. MECHANISM OF GLUCAGON ACTION
• Main target tissues: liver, muscle, and adipose tissue
• Glucagon prevents hypoglycemia by  cell production of
glucose
• Liver is primary target to maintain blood glucose levels
 Gluconeogenesis
 Glycogenolysis
REGULATION OF GLUCAGON INCREASE
• Increased blood glucose levels inhibit glucagon release.
• Amino acids stimulate glucagon release (high protein,
low carbohydrate meal).
• Stress: epinephrine acts on alpha cells, increasing
glucagon release (increases availability of glucose for

8. INSULIN FROM BETA CELLS
• ACTS ON TISSUES (ESPECIALLY LIVER, SKELETAL MUSCLE, ADIPOSE) TO
INCREASE UPTAKE OF GLUCOSE AND AMINO ACIDS.
• WITHOUT INSULIN, MOST TISSUES DO NOT TAKE IN GLUCOSE AND AMINO
ACIDS WELL
REGULATION OF INSULIN RELEASE
• MAJOR STIMULUS: INCREASED BLOOD GLUCOSE LEVELS
• AFTER A MEAL, BLOOD GLUCOSE INCREASES
• IN RESPONSE TO INCREASED GLUCOSE, INSULIN IS RELEASED
• INSULIN CAUSES UPTAKE OF GLUCOSE INTO TISSUES, SO BLOOD GLUCOSE
LEVELS DECREASE.
• INSULIN LEVELS DECLINE AS BLOOD GLUCOSE DECLINES

9.  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

10. Type I Diabetes Mellitus IDDM
b cells of the islets of Langerhans are destroyed by autoimmune
attack which may be provoked by environmental agent.
Glucose cannot enter the adipose cells.
Increased blood [glucagon].
TYPE II DIABETES MELLITUS NIDDM
Slow to develop.
Genetic factors are significant.
Occurs most often in people who are overweight.
Decreased sensitivity to insulin or an insulin resistance.
GESTATIONAL DIABETES
Some pregnant women require more insulin than their body can
produce.
IMPAIRED GLUCOSE TOLERANCE AND PREDIABETES
It is a condition in which blood glucose levels are higher than
normal but not high enough for a diagnosis of diabetes. Patients
are at high risk of developing type 2 diabetes.
INSULINOMA

11. SOMATOSTATIN
Secreted by D cells of the pancreatic islets.
Inhibits the secretion of several hormones including GH, TSH, Insulin, Glucagon and gastrin
Produces decrease in blood glucose concentration
PANCREATICPOLYPEPTIDE
Secreted by PP cells in the endocrine pancreas predominantly in the head of the
pancreas
Triggered by protein rich meals, fasting, exercise, and acute hypoglycemia.
Inhibited by Somatostatin
Exact biological role is uncertain
Physiological effect: Inhibition of contraction of gall bladder & pancreatic enzyme
secretion.