THE RELATIONS BETWEEN THE ENDOCRIN ORGANS 163 



motor cells in the peripheral ganglia. Some evidence has been published 

 by Camus and Roussy (b) which would indicate that the polyuria depend- 

 ing on hypophyseal disease might be due to local irritation of these centers, 

 as will be mentioned later. 



Distribution of Autonomic Components of the Nervous System. 

 STRUCTURES WITH EXCLUSIVE SYMPATHETIC INNERVATIONS. The fol- 

 lowing structures are believed to be supplied wholly, or almost wholly, by 

 fibers from the sympathetic system, both activation and inhibition of 

 action being accomplished through neurons belonging to the same system : 



1. The pilomotor muscles. 



2. The sweat glands. Physiologists, so far, have traced only 

 sympathetic fibers to these structures, yet, clinically, conditions of 

 general parasympathetic stimulation are accompanied by sweating. 

 For this reason some students of clinical visceral neurology are in- 

 clined to believe that the sweat glands have both sympathetic and 

 parasympathetic inervations, 



3. Blood Vessels. Vasoconstrictor and vasodilator effects are both 

 generally produced by nerves belonging to the sympathetic system. 

 Whether constriction or dilatation occur seems to depend upon the 

 nature and degree of stimulation. There are a few nerves, however, 

 which do not belong to the sympathetic system, but which are definite- 

 ly recognized as vasodilators, such as the chorda tympani, which di- 

 lates the vessels of the submaxillary glands, the small petrosal, which 

 dilates the vessels of the parotid gland, the lingual, which dilates the 

 vessels of the tongue, and the nervus erigens, which dilates the ves- 

 sels of the penis. Aside from these, each spinal sensory nerve, when 

 stimulated, has the property of causing dilatation of the superficial 

 vessels in the zone supplied by it. This is ordinarily regarded as a 

 true reflex effect, but there is some evidence that it may be a so-called 

 axon reflex, mediated through peripheral structures. 



4. Structures derived wholly from the miillerian and wolffian 

 ducts ; viz., fallopian tubes, body of the uterus, vas deferens, seminal 

 vesicles, and ureter. 



5. The suprarenal and thyroid glands and the anterior lobe of 

 the pituitary. 



< * 



STRUCTURES WITH EXCLUSIVE PARASYMPATHETIC INNERVATION. 

 There are certain structures which are believed to be supplied wholly by 

 the parasympathetics, such as the ciliary muscle, esophagus, and cardiac 

 end of the stomach. 



STRUCTURES WITH STIMULATORY PARASYMPATHETIC AND INHIBITORY 

 SYMPATHETIC INNERVATION. The following structures are activated by 

 the parasympathetics and inhibited by the sympathetics : 



