68 GENERAL BIOLOGY 



1. The olfactory ( ), nerves running from the 

 olfactory lobes to the nasal cavities. 



2. The optic nerves, running from the optic lobes, crossing each 

 other to form the optic chiasma and passing to the eye on the opposite 

 side of the head. 



3. Oculomotor, supplying the muscles of the eye. 



4. Trochlearis ( ), sometimes called the patheti- 

 cus, supplying the muscles of the eye. 



5. The Trigeminus ( ), or trifacial, a sensory 

 nerve, supplying the sides of the head. 



6. The Abducens ( ), supplying the muscles 

 of the eye. 



7. Facial, chiefly motor in its action and supplying the sides of the 

 head. 



8. Auditory, supplying the inner ear. 



9. Glossopharyngeal ( ), a sensory nerve, sup- 

 plying the pharynx and tongue. 



10. Pneumogastric ( ), or vagus, supplying the 



larynx, heart, and stomach. 



THE SYMPATHETIC SYSTEM 



The main trunks of this system consist of a nervous strand on each 

 side of the spinal column (Fig. 337). Throughout the abdominal cavity 

 one may see the chain of minute nerve ganglia, ten in number, which are 

 also connected with the spinal nerves. From these chains of ganglia tiny 

 nerves are given off, supplying the intestine, the kidney, and other ab- 

 dominal organs. 



Although the sympathetic system is connected with the spinal 

 nerves, it has entirely distinct and separate functions. Microscopically, 

 one finds quantities of neurones, each with its little cell-body, dendrites 

 ( ) and axon. These are massed in the brain and 



cord, as well as in the ganglia outside of the cord. Some of them carry 

 impulses to the center and some away from it. There are several 

 branches where a vast intermingling of the sympathetic strands is seen, 

 the principal ones being called the coeliac ( ) or 



solar plexus, supplying the stomach, intestine, liver, pancreas, spleen, 

 and sending fibers to the gonads and kidneys, and the urogenital plexus, 

 supplying kidneys and gonads primarily. 



