THE CIRCULATION THROUGH SPECIAL ORGANS 



435 



ter, on the other hand, continues to pursue a course along the spinal 

 column where it soon receives branches from the lumbar portion of 

 the spinal cord. Their points of union are marked by the lumbar 

 ganglia. The first three of these give rise to the splanchnici minores, 

 which pass directly across toward the suprarenal plexus. The ab- 

 dominal sympathetic continues downward and eventually connects 

 with the sacral nerves and the sympathetic system of the pelvis. 

 The left and right suprarenal plexuses, therefore, may be regarded 

 as the outposts of the abdominal sympathetic system. In addition 

 to these two plexuses, the latter includes the more centrally situated 

 ganglion mesentericum superior and the ganglion celiacum. All 

 these ganglia together with their extensive network of fibers and a few 



FIG. 226. DIAGRAMMATIC REPRESENTATION OF THE SPLANCHNIC SYSTEM (SOLAR PLEXUS). 

 T, thoracic sympathetic nerve divides into (S) greater splanchnic nerve and (A), 

 abd. symp. nerve. The former ends in the suprarenal plexus (B) and the latter in the 

 lumbar ganglia (LG). From the lumbar ganglia the three minor splanchnic nerves 

 pass to the supraienal plexus. M , Superior mesenteric and C celiac ganglia of the solar 

 plexus. The plexuses leading out from here are: /, renal plexus to kidney (K); II, 

 mesenteric plexus to intestine (J) ; ///, hepatic plexus to liver (L) stomach (St), pancreas 

 (P) and duodenum (D). IV, gastro-splenic plexus to spleen (Sp) and stomach (St); 

 Di, line of diaphragm. 



scattered small ganglia, form the so-called plexus Solaris. Thus, the 

 splanchnic nerves constitute the preganglionic paths and the different 

 nerves which connect the solar plexus with the aforesaid organs of the 

 abdomen, the postganglionic paths. 



The Vasomotors of the Kidneys and Suprarenal Bodies. These 

 organs do not belong to the portal system, because their blood is 

 drained directly into the inferior vena cava, but as they are innervated 

 by the splanchnic nerves, they may be conveniently included in this 

 discussion. In fact, it is customary to speak of those organs which 

 derive their nerve supply from the splanchnic nerves, as forming the 

 splanchnic system. This includes the portal organs, kidneys and 

 suprarenal bodies. Each kidney is innervated by fibers which are 

 derived from the suprarenal plexus and reach this organ by following 

 the highway of the renal artery. They form the so-called plexus 



