ALIMENTARY CANAL OF MAN 



119 



When the digestive glands are located some distance from the 

 food tube, they have a tube or duct which effects the discharge 

 of the secretion into the alimentary canal. 



Alimentary canal of man. The alimentary canal is a tube pass- 

 ing through the body, in which food is made ready for the use 

 of the organism. While food remains in the canal, it is actually 

 separated from the body because it can pass out of the body at 

 the posterior end of the tube without having affected the other 

 organs of the 

 body. Consider 

 the alimentary 



canal of the 

 worm. It is a 

 straight tube 

 passing from the 

 anterior to the 

 posterior end of 

 the animal's 

 body. It is a 

 tube within a 

 tube. Before 

 food is actually 

 in the body, it 

 must get from 

 that inner tube 

 into the sur- 

 rounding struc- 

 tures. The ali- 

 mentary canal of 

 man is a contin- 

 uous tube from 

 the mouth to the anus or end of the large intestine. There is much 

 variation in width in various sections, and it is twisted and coiled 



The digestive organs of man are displaced to some extent in this 

 illustration, in order to show clearly their relations to each other. They 

 are somewhat similar to those of the frog. Note the absence of a 

 cloaca, however. Higher animals have a large intestine but no cloaca. 



