Figure 2: Drawing schematizing the defensive loss of the gastric mucosa provoked by aggressive agents, unchaining peptic ulcerao (ROBBINS; COTRAN, 2010). The aggressive factors increase the permeability of the gastric mucosa to the acid clordrico. It is initiated then, a sequncia of events initiating with the direct injury of the gastric mucosa and after that the injury of the submucosa (RODRIGUES, 2008). The acid clordrico in contact with the fabric gastric forsaken provokes injury of capillaries that make the maintenance of the local sanguineous flow, beyond, to injure the nerves present in the stomach and with this to unchain exacerbados muscular espasmos (MILK, 2004). The acid clordrico excites the mastcitos, cells gifts in the submucosa and proper blade to liberate heparina and histamina gifts in its cytoplasmic granules.
The heparina, in special is an inhibitor of the sanguineous coagulation (IT WOULD MAKE, 2003). The histamina set free active the parietais cells to secretarem more acid clordrico, inflaming the fabric local, characterizing one edema accented. The exposition of the sanguineous capillaries of the mucosa the gastric secretion, modifies the local sanguineous flow. Other factors as the release of pepsina, use of AINES and alcohol modify the circulation, compromising the nutrition of the gastric cells and the repairing of the fabric affected (MILK, 2004). The fabric gastric also is affected in situations of estresse.
The Central Nervous System (SNC) is modified unchaining aggressive mechanisms. In situation of it estresse, the intestinal motilidade it is modified, one increases the stimulaton for release of acid clordrico, pepsina, histamina and the sanguineous capillaries are injured developing isquemia, necrosis and ulcer (MILL, 2007). Peroxidase in the fabric estresse it increases the lipdica enzyme gastric. This enzyme speeds up the lipdica peroxidao, exacerbando the production of free radicals. The free radicals injure the cellular membrane for coagular its constituent (proteins, acid nuclicos and lipdios). Thus, the fabric injured is edemaciado, hemorrhagic (figure 3) and necrosado (RODRIGUES, 2008).