MORPHOLOGY OF OPEN-TYPE APUDOCYTES OF THE GASTROENTEROPANCREATIC SYSTEM

Abstract

Among the local regulatory structures of organs, the local endocrine apparatus, consisting of endocrine cells singly located among the epithelial cells of the organ mucosa, has recently attracted more and more attention from researchers. The English histologist Pierce discovered a common property of these cells, which consists in the absorption of amine precursors by these cells and their decarboxylation, converting them into peptide hormones or biogenic amines. He combined these cells into a single system, calling it APUD - a system that is, the first letters of the English words "Amine Pecursare Uptake and Decarboxylation" meaning the absorption of amine precursors and their decarboxylation. The cells of this system are called apudocytes, among which there are open and closed type cells. Open type cells face their apical ends into the cavity of the digestive tract, airways and urinary tract. On this apical part there are microvilli, the plasma membrane of which contains specific receptor proteins. These cells receive information about the composition of food or exhaled air.