The jejunum is the midsection of the small intestine, connecting the duodenum to the ileum. It is about 2.5 m long, and contains the plicae circulares, and villi that increase its surface area. Products of digestion (sugars, amino acids, and fatty acids) are absorbed into the bloodstream here.
Not to be confused with the cells of the islets of Langerhans, found in the pancreas, or Langhans giant cell.
The islet density routes throughout the healthy human pancreas. The pancreatic islets or islets of Langerhans are the regions of the pancreas that contain its endocrine (i.e., hormone-producing) cells, discovered in 1869 by German pathological anatomist Paul Langerhans.