[Ultrastructure of the microcirculation bed of the stomach and duodenum in the bleeding ulcer zone].

According to the data obtained by electron-microscopy investigation of endotheliocytes from the bleeding ulcer zone there was noted the dominance of catabolic processes over synthetic, the creation of folds of endotheliocytes processes, what causes the capillaries lumen narrowing, the basal layer lysis. These factors are the starting mechanism of gastrointestinal bleeding occurrence.