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PKACTICAL PHYSIOLOGY 



On exciting the cervical sympathetic, or the sympathetic nerve 

 filaments which accompany the artery of the gland, the gland will 

 pale owing to vaso-constriction. A little thick secretion will at the 

 same time appear in the cannula. On exciting the chorda tympani, an 

 abundant secretion of thin watery saliva appears. At the same time 

 the gland becomes red and turgid. The same effect may be produced 

 reflexly by excitation of the central end of the lingual nerve. 



The submaxillary gland is enclosed in a firm capsule. It is fed by a 

 branch of the external maxillary artery which enters the hilus of the 

 gland. The gland also receives small branches from the great or 



Li 



O.c 



Fio. 201. Diagram of the submaxillary and sublingual glands and ducts and their 

 nerve supply from chorda tympani and sympathetic. F, facial ; Li, lingual ; ct, chorda 

 tympani; C.c.s., cervical sympathetic nerve; g 1 , submaxillary ; g 2 , sublingual 

 gland ; c.wa, e.c ducts of glands. (Bernard.) 



posterior auricular artery. The veins are usually two, but are variable. 

 One enters the internal and the other the external maxillary vein close 

 to where these veins join to form the external jugular vein. The blood 

 coming from the salivary gland can be collected by tying a cannula 

 in the external jugular vein and ligating all branches excepting those 

 coming from the gland. The exchange of blood-gases in the gland can 

 thus be determined. 



Nicotine, 30-40 mgrms. in dog, 10 mgrms. in cat, injected intra- 

 venously, paralyses the preganglionic fibres of the chorda tympani for 

 about 15 minutes. The ganglion cells of the submaxillary gland are in 

 or near the hilus of the gland. 



Atropine sulphate, 10-14 mgrms. in dog, 5-15 mgrms. in cat, injected 

 into the blood paralyses the secretory fibres of the chorda tympani, 

 while it leaves the vaso-dilator fibres untouched. Pilocarpine nitrate, 



