Elementary anatomy, physiology and hygiene for higher grammar grades . e stomach it passesthrough the coiled small intestine, which is subdividedinto duodenum, jejunum, and ileum. Passing from the 90 PHYSIOLOGiT ileum into the large intestine through a small openingit comes into the coecum, then passes upward, across, anddownward through the colon into the rectum. (Compare Fig. 22 with Fig. 21).The glands of thedigestive system arethe three pairs of sali-v,ary glands (theparo-tids, the sublinguals,and the submaxil-laries), the pancreas,and the liver. TheItver, however, haslittle to do with di-
Elementary anatomy, physiology and hygiene for higher grammar grades . e stomach it passesthrough the coiled small intestine, which is subdividedinto duodenum, jejunum, and ileum. Passing from the 90 PHYSIOLOGiT ileum into the large intestine through a small openingit comes into the coecum, then passes upward, across, anddownward through the colon into the rectum. (Compare Fig. 22 with Fig. 21).The glands of thedigestive system arethe three pairs of sali-v,ary glands (theparo-tids, the sublinguals,and the submaxil-laries), the pancreas,and the liver. TheItver, however, haslittle to do with di-gestion, and much todo with assimilationand excretion. Letus now look carefullyat each of these or-gans of digestion, andsee how each is madeand what part of thework of digestioneach performs. Themouth cavity isformed by the cheeks,the lips, the tongue,and the palate ; thelatter has an upperpart haid and bony,which extends back into a softer part from which theuvula hangs down. Between the Cheeks are the teeth,whose office it is to masticate the food and mix it with. Fig. 21.— A diagram of digestive , SI. & Sm., parotid, sublingual, andsubmaxillary glands; Ph., pharynx; Es.,esophagus; , vena cava vein receivingchyle through thoracic duct {^ fromlacteals {Lc.)\ Lv., liver; P., pancreas;iS., stomach; duodenum; C, caecum;, vermiform appendix. NTJTEITION 91 the saliva. There are two sets of the teeth, the tempo-rary set of twenty teeth, which is lost at about six years,and the permanent set of thirty-two teeth (Fig. 23).There are three parts to be distinguished in a tooth :the crown or part seenin the mouth, the rootor part which projectsinto the gums, and theline between which iscalled the neck. The teeth are com-posed of a hard, shiny,outside layer called theenamel, which acts asa protection to tlieteetli, the middle bonypart or dentine, andthe inner soft partor pulp, largely com-posed of blood vesselsand nerves (Fig- 24). Beginning in themiddle of t
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