The insulae pancreaticae (also called as the pancreatic islets or islets of Langerhans) are cellular masses consisting of several hundred cells lying in the interstitial tissue of the pancreas. They are composed of five different cell types that make up the endocrine portion of the pancreas and are the sources of insulin, glucagon, somatostatin, pancreatic polypeptide and gastrin.
The German pathologist, physiologist and biologist Paul Langerhans discovered the insulae pancreaticae in 1869 after realising that there was a sharp constrast between the well-researched physiology of the pancreas and its poorly-researched anatomy. In his 1869 publication we learn the following:
- That he conducted his research of the pancreas mainly on rabbits.
- That he discovered rounded masses (insulae pancreaticae) that consisted entirely of cells never-before-discovered and that the diameter of the masses was measured to be 0.1-0.2 millimetres.
- That the cells in those rounded masses were small and had irregular polygonal structures along with relatively clear cytoplasms. He also measured the cells’ diameter to be 0.0096-0.012 millimetres.
- That he noted that “These cells lie together, generally in greater numbers, diffusely scattered in the parenchyma of the gland.”
Here is a photomicrograph of a section of the pancreas with the insulae pancreaticae (islets of Langerhans) clearly labelled:
[ux_image_box img=”1391″ image_width=”60″ link=”http://medcell.med.yale.edu/systems_cell_biology/liver_and_pancreas_lab.php” target=”_blank”]
Here is a photograph of Paul Langerhans:
[ux_image_box img=”1395″ image_width=”40″ link=”https://en.wikipedia.org/wiki/Paul_Langerhans” target=”_blank”]