vi SYMPATHETIC SYSTEM 361 



which supply the unstriated muscles of the body (vessels, digestive 

 tract, excretory ducts, hair follicles), the myocardium, and the 

 secretory nerves to the glands, in contradistinction to the parts 

 of the nervous system which innervate the striated skeletal 

 muscles. But this division by peripheral distribution is not 

 always possible ; in some parts of the gut (e.g. in the upper parts 

 of the oesophagus and end of the rectum) striated muscle fibres 

 are controlled by the sympathetic system. 



Langley divides the entire Sympathetic or Autonomic System 



Fio. 195. Two nerve-cells from cervical ganglion of cat. Golgi's method. Highly magnified, 

 (v. Kolliker.) n, axon. 



into three parts : (a) the sympathetic in the strict sense of the 

 term ; (V) the cranial system (mesencephalic and bulbar), which 

 supplies the eye, upper part of the digestive tract, heart, and lungs ; 

 (c) the sacral system, which innervates the lower parts of the 

 digestive tract, the bladder, and the genital organs. We shall 

 frequently return to this classification. 



In its minute structure the sympathetic system presents the 

 same constituent elements as the rest of the nervous system, viz. 

 nerve-fibres, ganglion cells, and a complicated fibrillary network 

 around the ganglion cells which probably originates in the pro- 

 cesses of the nerve-fibres. The single nerve-fibres unite into nerve 

 trunks, while the ganglion cells and network of fibrils accumulate 

 at certain points along their course. 



