VASO-MOTOR NERVES OF THE LH^R 



425 



Tio. 153. 



Diagram showing the course of the A-asorrotor nerves of the liver, according to Cyon 

 and Aladoff. Tliese nerves are indicated ly ihe dotted line which pccompanies them 

 «, the vasomotor centre ; b, the trunk of the vagus; c, the vasomotor nerves of tlie liver 

 passing along the vertebial arterj' from the spinal cord to ihe third cervical ganglion; 

 d, the fibres connecting the third cervical and first dorsal ganglion. They pass on each side 

 of the subclavian artery, and form the annukis of Vieussens. Above e is the first dorsal 

 ganglion ; / the gangliated cord of the sympathetic ; g, the spinal cord ; h, the splanchni'^ 

 nerves ; i, the semilunar ganglion, from which vasomotor fibres pass to the hepatic and 

 intestinal vessels ; I:, the lungs to wliich fibres of the vagus are seen to be distributed; I, 

 the liver ; m, the intestine ; n, the arch of the aorta. 



Division of the vasomotor nerves of the liver by partial division of the spinal cord in the 

 neck or section of the fibres c or d causes diabetes, by allowing the hepatic vessels to dilate, 

 and the flow of blood through the liver to become more rapid. Division of the gangliated 

 -cord /, or the spknchnics h, would probably have a similar effect were it not that the vaso- 

 motor nerves of the intestine are contained in them as well as the nerves for the liver, and 

 therefore when they are divided the intestinal vessels dilate. The blood then goes to the 

 intestine, so that the circulation through the liver is not nicreased although its vessels are 

 dilated. Diabetes, therefore, does not result from section of /'or /(. 



Irritation of the vagus b, or of its branches, causes reflex dilatation of the hepatic vessels 

 and diabetes. A similar result sometimes follov/s irritation of the first and third icrvical 

 ganglia. 



Protrusion of the eyeballs was produced by Bernard, by irritating the branches con- 

 necting the first and second dorsal gang 1 1 with the spinal cord. The letter c lies between 

 these ganglia. 



