128 



PHYSIOLOGY. 



Fig. 38.* 



ganization, and central connexions, that 

 stimulation of any part of the mucous 

 membrane in which it ramifies, excites 

 instantly to contraction all the faucial 

 muscles supplied by the vagus and the 

 facial nerves, and the permanent irrita- 

 tion of its peripheral ramifications, as in 

 cases of sore throat, will affect other 

 muscles supplied by the facial nerves 

 also. It is, therefore, an excitor of the 

 movements necessary to pharyngeal de- 

 glutition. 



The par vagum. — The following con- 

 clusions may be adopted respecting the 

 functions of this nerve and its branches. 



1. That the vagus nerve contains fila- 

 ments both of sensation and motion. 



2. That its pharyngeal branches are 

 ?7iotor. 



3. That its superior laryngeal branch 

 is the sensitive nerve of the larynx, con- 

 taining a few motor filaments to the crico- 

 thyroid muscle. 



4. That the inferior laryngeal is the 

 principal motor nerve of the larynx. 



5. That the cardiac branches exert a 

 slioht influence on the movements of the 

 heart. 



6. That its pulmonary branches con- 

 tain both motor and sensitive filaments, 

 and exercise an important influence upon 

 the respiratory acts, for they cannot be 

 destroyed without retarding materially 

 the respiration, impeding the passage of 

 the blood through the lungs, and causing 

 oedema of these organs. 



7. That the oesophageal branches are 

 the channel through which the muscles 

 of that tube are excited, through the 



medulla oblongata, to contract. 



8. That the gastric branches influence the movements of the 

 stomach, and probably in some degree the secretions and the sensi- 

 bility of its mucous membrane ; but that their integrity is by no 



* Origin and distribution of eighth pair of nerves. 6. Origin of the glosso pharyngeal 

 nerve, "s. Trunk of tlie nerve. 9. Spinal accessory, 10. Ganglion of the pneumogastnc. 

 22. Origin of the spinal accessory. 



