PHYSIOLOGY OF NERVE TISSUE. 



81 



dendrites of the emissive or motor cell. With the reception of these 

 impulses there is apparently a disturbance of the equilibrium of its 

 molecules, a liberation of energy, and, in consequence, a transmission 

 outward of impulses through the efferent nerve to muscle, gland, or 

 blood-vessel, separately or collectively, with the production of 

 muscular contraction, glandular secretion, vascular dilatation or con- 

 traction, etc. The reflex actions take place, for the most part, through 



M 



FIG 10. DIAGRAM ILLUSTRATING REFLEX ACTION. (Kirke.) 



S. Sentient surface from which proceeds the afferent nerve. M. C. Motor or 

 emissive cell giving origin to efferent nerve which terminates in M. M. 

 Motor organ. G. Ganglion cell on afferent nerve. 



the spinal cord and medulla oblongata, which, in virtue of their 

 contained centers, coordinate the various organs and tissues con- 

 cerned in the performance of the organic functions. The movements 

 of mastication ; the secretion of saliva ; the muscular, glandular, and 

 vascular phenomena of gastric and intestinal digestion ; the vascular 

 and respiratory movements ; the mechanism of micturition, etc., are 

 illustrations of reflex activity. 



