CHAPTER XVIII 

 DISTURBANCES OF CIRCULATION 



Hypostatic Congestion. In extreme weakness of the 

 heart the blood tends to collect in the dependent por- 

 tions of the body. This condition is known as hypo- 

 static congestion. It occurs in low fevers and frequently 

 results in the formation of ulcerations or bed-sores. 



Local Hyperemia. This is a condition of increased 

 amount of blood in any part of the body. It may be 

 either active or passive. Active hyperemia or arterial 

 hyperemia may be functional, as in the ovaries at the 

 menstrual period, or pathologic, when it is due to dila- 

 tation of the arteries from vasomotor activity or from 

 injury and weakening of the walls of the arteries. The 

 hyperemic area is bright red in color, the temperature is 

 elevated, and there is slight swelling. 



Passive hyperemia, or venous hyperemia, is due to 

 obstruction of the outflow of the blood from the veins. 

 The obstruction may be due to thickening of the vessel 

 walls, to tumors, or to thrombi within the vessels. 

 Areas the seat of passive hyperemia are dark red in 

 color (cyanotic) and of lowered temperature, followed 

 soon by swelling and edema. 



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