Histology & Function of The Pancreas

Histology of the pancreas and pancreatic ducts, and its function and regulation

1. Cairo University
Faculty of Medicine
Histology Department
2013
Histology & Function of
The Pancreas
Candidates
1-Fatma Abdelnasser Ghoneim (768)
2-Fifi Sami (777)
3-Fatma Mahmoud Elshahed (770)
4-Fahima Elsharkawi (776)

2. Pancreas
Thepancreasis
aglandularorgan
in thedigestive
system
andendocrine
system
ofvertebrates

3. Histologyof Pancreas
Under a
microscope,stained
sections of the
pancreas reveal two
different types
ofparenchymaltissue.
Lightly staining
clusters of cells are
called islets of
Langerhansand
Darker-staining cells
formaciniconnected
to ducts .
..

4. The Acinus
The exocrine pancreas
is classified as
A compound
tubuloacinous
gland.The cells that
synthesize and
secrete digestive
enzymes are
arranged in grape-
like clusterscalled
acini

5. The Acinus
•LM :
pyramidal cells with ill_
distinct cell boundaries.
The nuclei are rounded and
basal. the Cytoblasmshows
basal basophiliaand apical
acidophilic zymogene
granules.
•Em:
tight junctionalcomplexes.
Many rER. Intra cellular
canaliculiare found
between acinarcells. The
golgiapparatus is supra
nuclear. apical
membrane_boundelectron
dense zymogengranules

6. Pancreatic Ducts
•Intercalated ducts
•Intralobular
ducts
•Interlobular
ducts
•Intralobarducts
•The main
pancreatic duct
-

7. Intercalated ducts
Intercalated
ductsreceive
secretions from
acini. They have
flattened cuboidal
epithelium that
extends up into the
lumen of the acinus
to form what are
calledcentroacinar
cells.

8. Intralobularducts
•Intralobular
ductshave a
classical cuboidal
epithelium and, are
seen within
lobules. They
receive secretions
from intercalated
ducts

9. •-Interlobular ductsare
found between lobules.
•The smaller forms have
a cuboidal epithelium,
while a columnar
epithelium lines the
larger ducts.
Intralobular ducts
transmit secretions
from intralobular ducts
to interlober ducts.
Interlobular ducts

10. Interlobarducts transmit secretions
from interlobular ducts to the
major pancreatic duct.Themain
pancreatic ductreceived secretion
from interlobular ducts and
penetrates through the wall of the
duodenum. In some species,
including man, the pancreatic duct
joins the bile duct prior to entering
the intestine.

11. Islets of Langerhans
•They are multiple
pale areas scattered
between the darkly
stained pancreatic
acini. They present
at the tail region in
number about one
million. They are
surrounded with
delicate reticular
fibers but not
capsulated

12. Cell types
•(1) Alpha cellsproducingglucagon(15–20% of
total islet cells)
•(2) Beta cellsproducinginsulinandamylin(65–
80%)
•(3) Delta cellsproducingsomatostatin(3–10%)
•(4) Epsilon cellsproducingghrelin(<1%)
•(5) PP cells(gamma cells) producingpancreatic
polypeptide(3–5%)
•(6) C_cellsmay represent immature or
degenerated cells (3%)
•(7) G_cellssecrete gastrin
•(8)Ganglion cells aggregated nerve cells,for
autonomic nervous control of the islets

13. Paracrinefeedback
* Insulin: activates beta cells and
inhibits alpha cells.
* Glucagon: activates alpha cells which
activates beta cells and delta cells.
* Somatostatin: inhibits alpha cells and
beta cell

14. Function of pancreas
(1) Endocrine
islets of Langerhans cells secrete hormones that
pass to the blood as: α cells secrete glucagon, β
cells secrete insulin, δ cells secrete
somatostatin, and PP cells secrete pancreatic
polypeptide
(2) Exocrine
The acinar cells producedigestive enzymes and
an alkaline fluid in response to the small
intestine hormones secretin and cholecystokinin
include trypsin, chymotrypsin, pancreatic lipase,
and pancreatic amylase

15. Regulation
•Sympathetic(adrenergic)
α2: decreases secretion from beta cells,
increases secretion from alpha cells
•Parasympathetic(muscarinic)
M3 increases stimulation from alpha cells
and beta cell

16. Diseases
•Diabetes, type 1
•Diabetes, type 2
•Cystic fibrosis
•Pancreatic cancer
•Pancreatitis
•Pancreatic pseudocyst
•Islet cell tumor
•Enlarged pancreas