CHAPTER XXXI 
DIGESTIVE ORGANS AND FOOD 
sopha^us 
326. Digestive Organs. — The digestive organs of man 
consist of the same parts which have already been described 
in the frog. Each region of the 
digestive organs is more perfectly 
developed and the biological princi¬ 
ple, the division of labor, reaches 
its highest development in man. 
The parts of the alimentary canal 
in man are: the mouth, containing 
the teeth, tongue, and glands ; the 
throat or pharynx; the esophagus, 
the stomach, the small and the 
large intestine. The last part of 
the large intestine is called the 
rectum. These several parts form 
a continuous tube, and each does 
a particular work in digestion 
(Figures 363 and 72). 
The mouth is lined with a soft 
kept moist by the 
saliva secreted by three pairs of 
glands, and poured into the mouth 
The spleen is not a digestive in sufficient quantities to moisten 
gland. The salivary glands con- the dry food and thus assist in 
shown swallowing. The tongue is a mus¬ 
cular organ and bears on its upper 
surface many small fleshy projections called papillce (pa- 
pil'le: Latin papilla, bud), some of which are fairly large 
404 
Figure 363. — Alimentary 
Canal of Man, with Its Two 
Chief Digestive Glands, the membrane 
Liver and Pancreas Con¬ 
nected with the Small In¬ 
testine. 
