Development of the endocrine system alpha cells. The insulin concentration within the fetal pancreas is 3.6 pmol/g at seven to ten weeks, which rises to 30 pmol/g at 16–25 weeks of gestation. Near term, the insulin concentration increases to 93 pmol/g. The endocrine cells have dispersed throughout the body within 10 weeks. At 31 weeks of development, the islets of Langerhans have differentiated. While the fetal pancreas has functional beta cells by 14 to 24 weeks of gestation, the amount of insulin that is released into the bloodstream is relatively low. In a study of pregnant women carrying fetuses in the mid-gestation and near term
Esophageal gland Esophageal gland The esophageal glands are glands that are part of the digestive system of various animals, including humans. Esophageal glands in humans are a part of a human digestive system. They are a small compound racemose exocrine glands of the mucous type. There are two types: Each opens upon the surface by a long excretory duct. Oesophageal gland is enlarged in large monoplacophoran species. Oesophageal gland or oesophageal pouch is a part of the digestive system of some gastropods. Oesophageal gland or pouch is a common feature in so-called basal gastropod clades, including Patelloidea, Vetigastropoda, Cocculiniformia, Neritimorpha and Neomphalina.