PART VI 

 THE AUTONOMIC SYSTEM 



The autonomic system is that part of the nervous 

 system which supphes organs which are not under the 

 control of the will. If we regard the primitive animal as 

 being composed of two tubes lying one within the other, 

 the autonomic system is that which is supphed to the 

 inner tube (the gut) and its diverticula. 



The disposition of the autonomic system will be more 

 readily understood if the following points be borne in 

 mind : — 



1, The fibres of this system issue from the central 

 nervous system in three situations — 



a. From the brain stem, accompanying certain of the 

 cranial nerves. This is the cranial autonomic. 



6. From the region of the cord which hes between the 

 cervical and lumbar swelhngs {thoracico-lumbar outflow). 

 The fibres issuing here, and these only, are the sympathetic. 



c. From the sacral region of the cord (sacral autonomic). 



These three regions are therefore separated by two 

 regions of the cord from which no autonomic fibres issue. 

 These are the cervical and lumbar swelhngs, which are 

 devoted entirely to the skeletal innervation of the hmbs. 



2. The general distribution of the autonomic system is 

 as follows — 



The cranial autonomic supphes the pupils, the sahvary 

 glands and their blood-vessels, the heart and lungs, the 

 ahmentary canal and its diverticula down to the lower end 

 of the small intestine. Also the kidney and spleen. 



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