Lecture on the Pancreas

Overview

• The pancreas is a large gland with both exocrine and endocrine functions.
• Majority of the pancreas consists of exocrine glands (~1.5 L of digestive enzymes daily) that secrete into the duodenum.
• Contains endocrine cells in clusters called islets of Langerhans.

Anatomical Structure

• Surrounded by a thin collagenous capsule.
• Capsule extends into the pancreas as septa forming lobules.
• Slide stained with Azen stain, highlighting collagen and connective tissue.

Exocrine Function

• Main functional tissue is called acini (Latin for berries).
• Secretory cells arranged around a central lumen, pyramid-shaped.
• Nuclei located near the base with rough endoplasmic reticulum.
• Secretory granules at the apices are zymogens (inactive enzymes).
• In acute pancreatitis, enzyme leakage causes inflammation.
• Presence of centroacinar cells marks the beginning of intercalated ducts.
• Ducts lined by simple cuboidal, transitioning to stratified cuboidal cells.
• Ducts drain into intralobular, then interlobular ducts, and finally into the main pancreatic duct.

Endocrine Function

• Islets of Langerhans contain lighter stained cells.
• Consist of beta cells (70%, secrete insulin), alpha (secrete glucagon), delta (secrete somatostatin), PP cells (secrete pancreatic polypeptide).
• Staining with Gomori helps differentiate cell types.
• Type 1 diabetes involves autoimmune destruction of beta cells.

Recap

• Pancreas has both exocrine and endocrine roles.
• Acini are the exocrine structures secreting digestive enzymes.
• Islets of Langerhans handle endocrine functions with a composition of multiple cell types.
• Staining techniques help identify different structures within the pancreas.