This document discusses the histology and microscopic anatomy of the pancreas. It describes the exocrine and endocrine components. The exocrine pancreas is composed of acinar cells that secrete digestive enzymes into small ducts. The endocrine pancreas is made up of islets of Langerhans, which contain alpha, beta, delta, and F cells that secrete glucagon, insulin, somatostatin, and pancreatic polypeptide respectively. The document also discusses pancreatic stellate cells and their role in fibrosis and repair after pancreatic injury.

1. Histology of
pancreas
Dr.Tim Mutafya
General Surgery resident-COSECSA
Kamuzu Central Hospital

2. Layout
1
Anatomical
relations
2
Macroscopic
pancreas
3
Microscopic
pancreas

5. Macroscopic
Gland volume
distribution
• 85% Exocrine pancreas
• 10% extracellular matrix
• 3% blood vessels and
ducts
• 2% endocrine pancreas

6. Microscopic
Acinar cells
• Digestion function
Islet of Langerhans
• Endocrine function
Pancreatic stellate cells
• Repair of injuries

8. Exocrine pancreas
• Has 3 functional units(lobule)
• Acinar cells
 synthesize and secrete the digestive
enzymes
• Centroacinar cells
 Secrete bicarbonate and mucin
 Represents beginning of ducts
• Intercalated ducts
 site of buffering secretions
No myoepithelial cells
around acini

9. Pancreatic Duct
system

11. Amylase
pancreas (40%-45%), salivary glands (55%-60%).

12. Endocrine pancreas
The secretory unit of endocrine pancreas
• The islet of Langerhans
• 2% of all pancreatic cells( 1-2million) and
Majority are located in the tail
• Demarcated from rest of parenchyma by
reticular fibers
The hormones of the endocrine pancreas are the
primary regulators of glucose, lipid and protein
metabolism.

13. • Islets are permeated by
many fenestrated
capillaries which allow
quick entry of pancreatic
hormones into the blood.
• The cells are connected by
desmosomes and gap
junctions forming bands or
cords of cells

14. - cells- Insulin
• 60- 70% of the islet cells. Contain many secretory granules
which possess a dark center with crystallized insulin,
surrounded by a wide pale halo.
A (alpha) cells
• 15-20% of the islet cells. Usually larger than B cells
• Secrete glucagon
• located peripherally in the islet.
• Have uniform granules filled with glucagon(thin hallo)
- cells- Somatostatin
• 5-10% of the islet cells.
• Diffusely distributed but most commonly in the periphery.
• Contain larger secretory granules compared to  and 
- cells - Pancreatic polypeptide
• <5% of the islet cells.
• They are mostly located within the head of the pancreas.
- cells -Glucagon
• 15-20% of the islet cells. Usually larger than B cells
• located peripherally in the islet.
• Have uniform granules filled with glucagon(thin hallo)
Islotes pancreáticos

16. Pancreatic stellate cells (PaSCs)
• Myofibroblast-like cells that are located in
exocrine regions of the pancreas
• Naturally in quiescent state
• Compose 4% of the total cell mass in the gland
• Located in periductal and perivascular regions of
the pancreas and contain vitamin A lipid droplets
in their cytoplasm.
PaSCs produce metalloproteinase and their inhibitors,
which assist in the turnover and remodeling of the
pancreatic extracellular matrix (ECM) after injury
• MMP-2, MMP-9, and MMP-13

17. Following activation, PaSCs migrate to
areas of tissue damage and contract,
phagocytose, and induce products that
regulate the ECM through facilitating repair
or by promoting fibrosis
Ethanol

18. inflammation or injury to the pancreas

19. Clinical significance of PaSCs
Chronic pancreatitis
• Persistent injury to the pancreas leads to the sustained
activation of the active PaSCs phenotype with
diminished production of MMPs leading to fibrosis and
pancreatic cell dysfunctions.
- chronic alcohol use,
- pancreatic duct obstruction or genetic.
Pancreatic cancer
Pancreatic tumor cells stimulate the proliferation of
PaSCs through the secretion of PDGF, and induce PaSCs
production of ECM proteins by secretingTGF-β1 and
FGF-2
Cancer Res. 2008;68(19):7707-7710. doi:10.1158/0008-5472.CAN-08-1132

20. summary

21. References
1. https://www.kenhub.com/en/library/anatomy/pancreas-histology
2. https://doi.org/10.1016/S0039-6109(16)36593-8
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4. Slideshare
5. Bailey & Love’s Short Practice of Surgery 28th Edition PDF