The document summarizes the pancreas, its functions, cell types, and hormone regulation. The pancreas is both an endocrine and exocrine gland located near the duodenum. It contains clusters of cells called islets of Langerhans that secrete hormones. The four major cell types are alpha cells that secrete glucagon, beta cells that secrete insulin, delta cells that secrete somatostatin, and F cells that secrete pancreatic polypeptide. These hormones work together to regulate blood glucose levels through secretion, absorption, and energy storage.

1. PANCREAS
SECRETION, FUNCTION AND
REGULATION
SELINA SRAVANTHI
SAROJINI NAIDU VANITA PHARMACY MAHA VIDYALAYA,
TARNAKA, HYDERABAD, TELANAGANA

2. PANCREAS
• Both an endocrine gland and an exocrine gland.
• A flattened located in the curve of the duodenum,
the first part of the small intestine, and consists of a
head, a body, and a tail.
• Roughly 99% of the cells of the pancreas are
arranged in clusters called acini.
• The acini produce digestive enzymes, which flow
into the gastrointestinal tract through a network of
ducts.
• Scattered among the exocrine acini are 1–2 million
tiny clusters of endocrine tissue called pancreatic
islets or islets of Langerhans.

3. Cell Types in the Pancreatic Islets
• Each pancreatic islet includes four types of
hormone-secreting cells:
• Alpha or A cells constitute about 17% of
pancreatic islet cells and secrete Glucagon
• Beta or B cells constitute about 70% of pancreatic
islet cells and secrete insulin
• Delta or D cells constitute about 7% of pancreatic
islet cells and secrete somatostatin (identical to
the growth hormone–inhibiting hormone secreted
by the hypothalamus).
• F cells constitute the remainder of pancreatic islet
cells and secrete pancreatic polypeptide.
• The interactions of the four pancreatic hormones
are complex.

4. CELL SECRETION FUNCTION REGULATION
Alpha or A cells Glucagon Raises blood glucose level by
accelerating breakdown of
glycogen into glucose in liver
(glycogenolysis), converting
other nutrients into glucose in
liver, (gluconeogenesis), and
releasing glucose into the blood
Decreased blood level of glucose,
exercise, and mainly, protein meals
stimulate secretion; somatostatin
and insulin inhibit secretion.
Beta or B cells Insulin Lowers blood glucose level by
accelerating transport of glucose
into cells, converting glucose
into glycogen (glycogenesis), and
decreasing glycogenolysis and
gluconeogenesis; also increases
lipogenesis and stimulates
protein synthesis
Increased blood level of glucose,
acetylcholine (released by
parasympathetic vagus nerve fibers),
arginine and leucine (two amino
acids), glucagon, Glucose-
dependent insulinotropic peptide
(GIP), hGH, and ACTH stimulate
secretion; somatostatin inhibits
secretion.
Delta or D cells Somatostatin Inhibits secretion of insulin and
glucagon and slows absorption
of nutrients from the
gastrointestinal tract
Pancreatic polypeptide inhibits
secretion
F cells Pancreatic
Polypeptide
Inhibits somatostatin secretion,
gallbladder contraction, and
secretion of pancreatic digestive
enzymes
Meals containing protein, fasting,
exercise, and acute hypoglycemia
stimulate secretion; somatostatin
and elevated blood glucose level
inhibit secretion.