168 



DIGESTION 



will be simple. But if the food is varied in its composition, and 

 largely made up of food-stuffs that require many changes before 

 they are fitted for absorption or before they can be utilized by the 



Xose. 



Submaxillary 



and sublingual 



glands. 



Trachea. 



Liver. 

 Gall-bladder. 



Duodenum. 



Large intestine. 



Vermiform appendix. 



Parotid gland. 



Thoracic or 



chyle duct. 

 Esophagus. 



Small intestine. 



Anus. 



FIG. 92. General scheme of the digestive tract, with the chief glands opening 



into it. 



tissues after they are absorbed, then the digestive apparatus that 

 is, the group of organs concerned in digestion will be complex. 

 Such is the character of the food of man, and, consequently, such 

 is the character of his digestive apparatus (Fig. 92). 



The human digestive apparatus consists of the alimentary canal 

 and the other digestive organs, which, although outside, still com- 

 municate with this canal by ducts through which their secretion 

 is poured. The alimentary canal consists of the mouth, the 

 esophagus, the stomach, and the small intestine. The digestive 

 organs which are outside, but which discharge their secretion 





