The endocrine (i.e., hormone-producing) cells of the pancreas are grouped in the<unk> . Discovered in 1869 by the German pathological anatomist Paul<unk> , the<unk>  constitute approximately 1 to 2% of the mass of the pancreas. There are about one million<unk>  in a healthy adult human pancreas, which are interspersed evenly throughout the organ, and their combined weight is 1 to 1.5 grams.
Islets of Langerhans
Inner cell mass
Mesenteric glands
Junctional epithelium
Hair follicle
Myoporum laetum
Fundic glands
Olfactory epithelium