MOVEMENTS OF THE ALIMENTARY CANAL. 



639 



say that the deglutition reflex is controlled by a definite nervous 

 mechanism the final motor cells of which are scattered in the several 

 motor nuclei of the efferent nerves mentioned above. 



The Anatomy of the Stomach. The stomach in man belongs 

 to the simple type as distinguished from the compound stomachs 

 of some of the other mammalia, the ruminating animals, for 

 example. Physiological and histological investigations have shown, 

 however, that the so-called simple stomachs are divided into parts 

 that have different properties and functions. The names and bound- 

 aries of these parts can not be stated precisely, since they vary in 

 different animals, and moreover there is at present an unfortunate 

 want of agreement among different authors regarding the nomen- 

 clature of the parts of the stomach.* For the purposes of a physio- 

 logical description we may use the names indicated in the accom- 

 panying schematic figure. The main interest lies in the separation 



num., 



J-Pyiorus- 



Pyloric part of stomach 

 or antrum. jbyiori. 



Position, of 

 traitsuersebcmcL 



Intermediate or 

 jorebylorie regioru 



Fig. 253. Schematic figure to show the different parts of the stomach. (After Retzius.) 



of the pyloric part of the stomach or antrum pylorif from the main 

 cavity of the stomach. The line of separation is marked by a 

 fissure on the small curvature, incisura angularis (/. A.) and on the 

 large curvature by an abrupt change of direction. The pyloric part 

 makes an angle, therefore, with the body of the stomach and differs 

 from the latter in its musculature, the macroscopical and microscopi- 

 cal characteristics of its mucous membrane, and in its functional 

 importance. The main body of the stomach falls into two sub- 

 divisions, whose line of demarcation is, however, indefinite. The 

 fundus proper is the blind, rounded end of the stomach to the left 

 of the cardia and projecting toward the spleen. The intermediate 

 or prepyloric region shows in many animals a characteristic struc- 



* See His, " Archiv f . Anatomie, "1903, p. 345. 



t Some recent writers confine this term antrum pylori to that portion 

 of the pyloric region bordering upon the pyloric orifice. 



