[Internal organs as a blood depot during different extreme exposures]

The results of an experimental study of fluctuations in the relative content of blood in 15 internal organs on exposure of the intact organism to the effect of various factors are discussed. A total of 25 experimental series was conducted, with 14 animals used in each series. Four types of regional blood redistribution reactions were distinguished according to the changes in blood filling (in the brain, heart, liver, and other organs of the abdomen and true pelvis). In most cases these reactions are accepted as a sign of mobilization of the dynamic intravascular blood reserve from the large-capacity vessels, mainly of the abdominal organs and organs of the true pelvis, with or without the participation of the liver, and also as a sign of utilization of the "reserve" blood in organs and tissues experiencing functional stress. The results of correlative analysis bear evidence of the reciprocal character of fluctuations in the amount of blood during stress, in the brain, lungs, and heart on the one hand and in the organs of the abdomen and true pelvis on the other, and also testify to the autonomous character of changes in the amount of blood in the liver. The internal organs of the abdomen and true pelvis are not a functionally single vascular region.