Islets of Langerhans

• Endocrine component of the pancreas, comprises 1-2% of the glands in adults.
• There are over one million islets of Langerhans in the pancreas, they are found all over the pancreas but are more numerous in the tail.
• A thin layer of connective tissue separates the islets from the surrounding connective tissue, but they are not truly encapsulated.
• Two types of islets

1. Compact (90%)
2. Diffuse (restricted to the head of the gland)

• Each endocrine cell produces produces one specific kind of peptide

1. Beta cells: insulin
2. Alpha cells: glucagon
3. Delta cells: somatostatin
4. PP cells: pancreatic polypeptide

• There is also a small number of individual endocrine cells scattered among the acini (Mills et al 2007).