DIGESTION 



153 



their organic constituents into the lumen of the acinus, materials that col- 

 lectively constitute the saliva characteristic of any one of the glands. This 

 continues until mastication ceases, when all the structures return to their 

 former condition of relative inactivity. 



The Nerve Mechanism of Insalivation. The nerves and nerve-cen- 

 ters that constitute the nerve mechanism for the secretion of saliva, as de- 

 termined by experimental investigations are shown in the following table: 



Afferent Nerves. 



i. Lingual and buccal branches of 

 the trigeminal nerve. 



Nerve-centers. 

 Medulla oblongata. 



Taste fibers 

 tympani. 



in the chorda 



3. Taste fibers in the glosso- 

 pharyngeal. 



Efferent Nerves. 



The chorda tympani and its post- 

 ganglionic continuations for the sub- 

 maxillary and sublingual glands; 

 the glosso-pharyngeal nerve and its 

 post-ganglionic continuations con- 

 tained in the auriculo-temporal 

 branch of the trigeminal nerve, for 

 the parotid gland. 



The sympathetic nerve, both pre- and 

 post-ganglionic fibers, for all the 

 glands. 



The Efferent Nerves. The efferent nerve-fibers, as stated in the fore- 

 going paragraph, that transmit nerve impulses to the : submaxillary sub- 

 lingual, and parotid glands, as well as to their associated blood-vessels, belong 

 to the autonomic system, and are contained respectively in the chorda tym- 

 pani and its post-ganglionic continuations, in the glosso-pharyngeal and its 

 post-ganglionic continuations contained in the auriculo-temporal branch 

 of the fifth nerve, and in the post-gangliomc branches of the sympa 

 thetic nerve derived from the superior cervical ganglion. Jhat these nerves 

 transmit the nerve impulses to the salivary apparatus is shown by t] 

 that follow their division and stimulation. 



rteCfe^r^^^ 



the facial (though it consists in part of autonomic nerve-fibers) the Mrunk of 

 which it leaves in the aqueduct of Fallopius. It then W^g?^ 

 cavitv emerges through the Glaserian fissure, and joins the lingual bra 

 of Te'inTerior maxillary division of the fifth nerve. After passing forward 

 as far af the sublbgual gland, nearly all of the fibers leave the lingual nerve 

 S^ft^SB to'become connected by terminal Mf 

 ganglion cells in relation with the submaxillary and sublingual 



on the secretion and flow of saliva from the submaxillary 



^SS^ and stimulation of the 

 are shown in the following way: A cannula is inserted 





