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HISTOLOGY OF PANCREAS
BY
DR. MUDASSAR ALI ROOMI(MBBS, M. PHIL)
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PANCREAS
The pancreas is an
elongated structure that lies
in the epigastrium and the
left upper quadrant. It is soft and lobulated and
situated on the posterior
abdominal wall behind the
peritoneum(RETROPERITONEAL).
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PANCREAS
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PANCREAS
Exocrine Pancreas Most of the pancreas is an exocrine
gland.
Pancreas is a compound tubulo-
alveolar gland of purely serous variety.
The secretory acini are subdivided into
lobules and bound together by loose
connective tissue.
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ACINAR CELL OF PANCREAS
Pyramid-shaped acinar cells
RER : Abundant, Basal Basophila.
apices are filled with secretory
granules (zymogen granules).
These granules contain the
precursors of several pancreatic
digestive enzymes that are
secreted into the excretory ducts
in an inactive form
(TRYPSINOGEN,
CHYMOTRYSINOGEN etc).
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PANCREAS
Stroma of pancreas: Thin C.T. capsule
Septa divide the pancreas into lobules
Within the lobules fine connective
tissue surrounds the parenchymal units(acini).
Exocrine pancreas has less blood supply
than that of endocrine pancreas
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PANCREAS
Excretory ducts
Start from within the center of
individual acini as pale-staining
centroacinar cellsshort intercalatedducts Intralobular ductslargerinterlobular ductsmain pancreaticduct.
do not have striated ducts.****
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PANCREAS
Endocrine Pancreas
Scattered among theexocrine acini
In human most numerous intail of pancreas***
Pancreatic islets (ofLangerhans)
Isolated, pale-staining vascularizedunits
Each islet is surrounded by finefibers of reticular connectivetissue.
With special immunocytochemicalprocesses, four cell types can beidentified in each pancreatic islet:
alpha, beta, delta, and pancreaticpolypeptide (PP) cells.
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Pancreatic Islet
These are richly vascularizedspherical clusters (100-200um) of Pale-staining cells.
Cells are arranged in cordsand clumps,
between which are found fineconnective tissue fibers and a
capillary network.
A thin connective tissuecapsule separates theendocrine pancreas from theexocrine serous acini.
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Pancreatic Islet (Special Preparation)
Alpha (A) cells are 20% = Glucagon The cytoplasm of alpha cells stains pink
Location = peripheral
Acts to elevate blood glucose level
Beta (B) cells are 70 % = Insulin Cytoplasm of beta cells stains blue.
Location = mainly central
Predominate Acts to decrease blood glucose level.
Delta (D) cells are less than 5 %: Least abundant
Variable cell shape
May occur anywhere in the pancreatic islet.
Produce somatostatin
Inhibit the release of hormones by nearby cells andreduces the motility of GIT and gall bladder.
G cells: produce gastrin which stimulate gastric HCLsecretion
PP cells: Pancreatic polypeptide cells Produce pancreatic polypeptide
inhibits production of pancreatic enzymes and alkalinesecretions.
Capillaries around the endocrine cells demonstrate therich vascularity of the pancreatic islets.
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Regulation of pancreatic secretin
secretin and cholecystokinin (CCK) regulate pancreaticsecretions.
Secretin Causes the production of watery fluid rich in sodium bicarbonate
ions. Neutralize the acidic chyme
Cholecystokinin (CCK), fats and proteins in the small intestine
Stimulates the acinar cells to produce Digestive enzymes: Pancreatic amylase for carbohydrate digestion
Pancreatic lipase for lipid digestion Deoxyribonuclease and ribonuclease for digestion of nucleic acids
Proteolytic enzymes trypsinogen,
chymotrypsinogen,
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PANCREAS- microscopic view
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HOW TO DRAW IT!
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CLINICAL:DIABETES MELLITUS
TYPE I DIABETES
MELLITUS
TYPE II DIABETES
MELLITUS
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CLINICAL:
Zollinger Ellison Syndrome
Tumor of gastrin produncing cells
Intractable peptic ulcers.
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CLINICAL
CANCER OF PANCREAS
Cancer of the Head of
the Pancreas and the
Bile Duct
Because of the closerelation of the head of
the pancreas to the bile
duct, cancer of the
head of the pancreasoften causes
obstructive jaundice.
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Blockage of the Hepatopancreatic Ampulla and
Pancreatitis
Cause: may be caused
by GALLSTONES
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CLINICAL
The Pancreatic Tail and Splenectomy
The presence of the tail ofthe pancreas in thesplenicorenal ligamentsometimes results in its
damage duringsplenectomy.
The damaged pancreasreleases enzymes that
start to digestsurrounding tissues, withserious consequences.
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Trauma of the Pancreas
The pancreas is deeply placedwithin the abdomen and is wellprotected by the costal marginand the anterior abdominal wall.
However, blunt trauma, such as ina sports injury when a sudden
blow to the abdomen occurs, cancompress and tear the pancreasagainst the vertebral column.
The pancreas is most commonlydamaged by gunshot or stabwounds.
Damaged pancreatic tissuereleases activated pancreaticenzymes that produce the signsand symptoms of acuteperitonitis.
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