108 



PSYCHOBIOLOGY 



intermediacy of terminal ganglion-cells), and also cause dilation of the 

 arterioles in the glands and hence increased blood supply. The effects of 

 currents in the sympathetic fibers are not clearly marked, but include secre- 

 tion and vaso-constriction. Apparently salivary gland action is controlled 



Stenson's duct 

 OriOce of duct 

 Parotid gland 



Masseter (cut) 



Mucous membrane 



(cut) 



Deep process of 



submaxillary gland 



Mylohyoid muscle 

 (cut) 



Submaxillary gland 



Lower border of 

 mandible 



Mylohyoid muscle 



Anterior belly of 



digastric 



Hyoid bone 



Duct of Bartholin (rare) 

 Wharton's duct 

 Duct 6f sublingual gland 

 Sublingual gland 



Fig. 79. The Salivary glands and their ducts. (After Cunningham.) The greater 

 portion of the lower jaw and part of the masseter muscle have been removed to show 

 the sublingual gland and the lower part of the submaxillary gland. Four ducts of 

 the sublingual gland are shown, opening on the floor of the mouth, and a fifth (duct 

 of Bartholin) opening into Wharton's duct. Wharton's duct and Stenson's duct are 

 the drains of the submaxillary and parotid glands respectively. 



entirely by nerve action. Secretion is normally started by the tact and 

 taste of food within the mouth and by the smell and sight of food. Reflex 

 habits may easily be built on arbitrary stimuli, such as sounds. The ring- 

 ing of a bell or the sounding of a tuning fork or the sight of a placard 

 may become a salivary excitant for a dog as well as for a man. 



