CHAPTER XII 



EFFECTS ON THE PERIPHERAL NERVOUS SYSTEM 



As might be expected, the peripheral nervous system resembles the central 

 nervous system in its notable resistance to inanition, likewise in showing a 

 marked susceptibility to certain types of partial inanition (pellagra, beriberi, 

 thirst). The effects of inanition upon the peripheral nervous system will 

 first be summarized briefly, and then considered in detail under (^4) total inani- 

 tion, and (B) partial inanition. 



Summary or Effects on the Peripheral Nervous System 



In general, the peripheral nervous system, like the central, appears relatively 

 resistant to inanition. The nerve cells, however, in both spinal and sympathet- 

 ic ganglia, may show progressive degenerative changes, including cytoplasmic 

 atrophy, vacuolation and chromatolysis as well as nuclear changes, similar to 

 those found in the central nervous system. The spinal ganglion cells and 

 stroma in amphibia contain small fat droplets, which are chiefly resorbed during 

 inanition. The nerve cell changes in general appear variable in the different 

 types of partial inanition, being most pronounced in pellagra, in which pigmen- 

 tary atrophy is frequent. 



Although the medullated nerve fibers are also resistant, the myelin sheath 

 may show a slight degree of atrophy, especially in extreme stages of inanition. 

 Wallerian degeneration may also occur, probably secondary to the above 

 mentioned degenerative changes in the nerve cells. The nerve endings in 

 muscle appear but slightly affected. Atrophy and degeneration of the periph- 

 eral nerves, including cranial, spinal and sympathetic, are also found variably 

 developed in the different types of partial inanition. They occur in pellagra, 

 and are especially characteristic of beriberi (excepting in mice and rats), 

 although they may be slight or absent unless the disorder is somewhat prolonged. 

 In aqueous inanition, a notable decrease in the weight of the sciatic nerve trunk 

 has been demonstrated in adult rats, which may be due partly to the loss in the 

 included adipose tissue. In the young rat, there is during thirst a persistent 

 growth in weight of the sciatic trunk, similar to that occurring in the spinal cord 

 during inanition. 



During inanition the perineurium and endoneurium may undergo prolif- 

 eration, and the resulting fibrosis tends to replace the loss in substance due to 

 atrophy) of the neurones. In certain types of partial inanition (pellagra, 

 beriberi and thirst), the changes may resemble those of a chronic neuritis, with 

 round cell infiltration. 



In this connection it may be recalled (as shown in Chapter III) that a 

 relatively marked resistance of the nervous system to inanition was likewise 



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