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As well as any adaptive reaction, activation of simpaticoadrenal system leads as to positive, and negative consequences, shown blood circulation centralization. Increase of a tone of veins and peripheral arteriolespasm are caused by influence of simpaticoadrenal system. Generally there is alpha-adrenergy stimulation. Therefore the peripheral spasm is uneven – arteriola of skin, an abdominal cavity and kidneys, where a large number of alpha-adrenoreceptors are more narrowed. On the contrary, coronary and brain vessels are poor in these receptors and the vazokonstriktion in them isn't present. Thus, the brain and heart are provided with blood at the expense of other bodies is so-called, blood circulation centralization – biologically expedient reaction.
At the same time centralization of blood circulation leads to the expressed decrease in a blood-groove in a liver, kidneys, hypodermic cellulose. The lowered peripheral blood-groove and an arterial gipoksemiya lead to development of an anaerobic metabolism with accumulation in fabrics and blood of organic acids –acidosis that promotes expansion of capillaries develops and sekvestration in them 10% of VCB - so centralization is replaced by decentralization of blood circulation and conducts in the final result to loss of effective VCB, uncontrollable hypotonia and death.
All adaptive mechanisms have also the back. The blood circulation centralization keeping life within several hours along with protection of a brain and heart, conceals in itself the danger of death though more remote. This danger consists in deterioration of microcirculation, a hypoxia of fabrics and violation of a metabolism in bodies and fabrics.
At decrease the volume pressure in capillaries is considerably slowed down a blood-groove up to a full stasis of blood. In these conditions erythrocytes and other uniform elements of blood stick together among themselves and form large units, peculiar traffic jams which worsen microcirculation up to development of a sludge-syndrome even more.
Development of a hyper coagulative syndrome is an inevitable consequence of delay of a capillary blood-groove. It leads to a dissemination intravascular coagulation syndrome ((DICS) that not only strengthens disorders of capillary blood circulation, but also serves as the base of irreversibility of hemorrhagic shock.
Thus, the main functional frustration at blood loss first of all are connected not only with decrease in level of hemoglobin, and with reduction of VCB, disorders of microcirculation and with violation of the curtailing properties of blood.
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