HYPEREMIA. CONGESTION. 



Definitiou. Forms, active — arterial, passive — mechanical — venous. De- 

 termination of blood. Causes of active congestion. Vaso-raotor nerves. 

 Lesion of spinal cord ; or of sympathetic nerve. Reflex irritation. Cen- 

 tral cause. Physiological hyperaemia. Medicinal hypersemia. Bacteri- 

 dian (toxic) hyperemia. Arterial obstruction. Thrombus, tumor. Cold, 

 chill. Removal of pressure. Cardiac hypertrophy. Symptoms, bright 

 red color, swelling, dropsy, migration of cells. Rise of local temperature. 

 Tenderness. Altered function. Causes of passive congestion. Obstructions 

 in the lungs, heart, veins. Diminished force of circulation from age, de- 

 bility, arterial disease, distance from the heart, decubitus, vaso-motor dis- 

 order. Gravitation— hypostatic congestion. Tumors. Paresis. Symp- 

 toms. Cyanosis. Distended veins. Coldness. Transudation — watery. 

 Haemorrhage. Thrombus. Hyperplasia. Atrophy. Postmortem lesions. 

 Treatment. Remove Cause. Correct injurious gravitation. Correct any 

 fault in blood pressure. Derivation. Constringe or support part. Mas- 

 sage. Electricity. Improve general health. 



Definition. An excess of blood in a part. It is distinguished 

 from inflammation by the absence of that tissue reaction, which 

 leads to or constitutes the special phenomenon of that morbid pro- 

 cess. 



Hypersemia is divided into active or arterial and passive, me- 

 chanical or venous. A capillary form has also been described 

 but usually capillary congestion is seen in both the arterial and 

 venous types. 



I. Active or Arterial Determination of blood. In this 

 form the arteries are dilated under a direct nervous influence. 

 Causes. In all the regular functions of the body, the flow of 

 blood is under the direct control of the vaso-motor nerves which 

 proceed from the spinal cord, through the branches of the sympa- 

 thetic to be distributed with the blood vessels. The hard pulse of 

 pleurisy is due to rigid contraction of the constrictor muscles under 

 the action of the vaso-motor nerves, and the blush of shame is due 

 to their relaxation. Some claim an active dilatation of the arte- 

 rial muscular coats, others look more simply upon the dilatation 

 as a mere yielding of the coats under the blood pressure, when 

 the constrictor muscles are relaxed. This vaso-motor paresis may 

 be induced : ist, by any lesion of the spinal cord. 2d, by the 



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