specimen Page of Patau's Veterinary Physiology. 



THE FOOD AND DIGESTION 



307 



up and prepared for digestion. In the horse the lips are 



long and prehensile, and are essential for the taking of food. 



Into the mouth three pairs of compound glands — the 



Salivary Glands — open. The 



parotid, lined entirely by 



enzyme-secreting epithelium, 



opens on the side of the 



cheek, while the submaxillary 



gland, composed partly of acini 



with enzyme - secreting, and 



partly of acini with mucin- 



secreting epithelium, and the 



sub-lingual, composed entirely 



of mucin-secreting acini, open 



under the tongue (S.G.). 



The tongue in the horse is 

 smooth, but in the ox, and 

 especially in the cat, it is 

 covered with a fine fur of 

 processes, the filiform papilla, 

 which are of use in passing 

 the food backwards along its 

 surface in the act of swalloAv- 

 ing. (For Organs of Taste see 

 p. 132.) 



Posteriorly, the mouth opens 

 into the pharynx (Ph.) or upper 

 part of the gullet. In the 

 horse the soft palate is very 

 long, reaching to the base 

 of the epiglottis, and, unless 

 during swallowing, shutting oft 

 the mouth from the pharynx 

 (Fig. 137). On each side, 

 between the mouth and the 



pharynx, is the tonsil (T.), an almond-Hke mass of lymphoid 

 tissue. The pharynx is a cavity which can be shut off 

 above from the posterior nares by raising the soft palate, 

 and by pulling forward the posterior pharyngeal wall. It is 

 surrounded by three constrictor muscles, which, by contracting 



Pig. 138. — Diagram of the Parts of 

 the Alimentary Canal, from Mouth 

 to. Anus. T., Tonsils; Ph., 

 Pharynx; S.C., Salivary Glands; 

 Oc, CEsophagus ; C, Cardiac; 

 Py., Pyloric Portion of Stomach ; 

 i). , Duodenum; Li., Liver; P., 

 Pancreas ; ./■., Jejunum; /., Ileum ; 

 v., Vermiform Appendix; Col., 

 Colon ; li., Rectum, 



