Histology of Pancreas by Dr. Roomi

8/1/2019 Histology of Pancreas by Dr. Roomi

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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,

procarboxypeptidase.10-May-12


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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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Histology of Pancreas by Dr. Roomi

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