VASODILATOR NERVES 



71 



16. Vaso-dilator Nerves,— Our consiaeration of vaso- 

 motor nerves has so far led us to the view that the dilation 

 or wideaing of an artery which leads to increase blood- 



a.f. a.f. 



■/-- V.M.C. 



•Sp.C. 



c.f, 

 •c.f. 

 c.f. 



-Sp.C. 



Fig. 22.— Diagram to illfstrate the Position of the Vaso-Motob 

 Centre, the Paths of Vaso-Constrictor Impulses from the Centre 

 along the Cervical .Sympathetic Nerve and (part of) the Ab- 

 dominal Splanchnic, and the Course of Impul-ses to the Centre 

 from the Brain and from an outlying Part of the Body. 



Sp.C, Sp.C. spinal cord ; V.M.C. va-so-motor centre ; Art. artery of ear; 

 C.Sy. cervical sympathetic; S.C.G. superior cervical ganglion; I.C.G 

 inferior cervical ganglion; S.Ait. subclavian artery; A.V. annulus of 

 Vieussens ; St.G. stellate ganglion ; 4, 5, 6, 7, 8, fourth, fifth, sixth, 

 seventh and eighth thoracic ganglia; A.S. upper roots and part of ab- 

 dominal splanchnic nerve.' The dotted lines a.f., a.f. indicate paths of 

 conduction for impulses to the vaso-motor centre from the brain. The 

 dotted lines c.f., <•./., c.f. indicate paths for the passage of impulses to tlie 

 vaso-motor centre from some outlying part of the body such as tlip skin. 

 The .irrows show the directions in wliich the impulses travel along 

 each path. 



