252 



HISTOLOGY 



appropriately known as the fundus gastri (the bottom of the stomach). Recently 

 the gastric canal (canalis gastri) has been recognized along the lesser curvature of the 

 human stomach. It is a channel, highly developed in ruminants, which conveys liquids 

 from the cardia to the pars pylorica, when the stomach is filled with more solid contents. 

 Ordinarily open toward the interior like a groove, it may become closed as a tube 

 during its physiological activity. Beyond the cardia there is a conical expansion of 

 the oesophagus, not always well defined, known as the cardiac anlrum, and beyond 

 the pylorus is the first part of the duodenum, or duodenal antrum. (A further account 

 of the development of these subdivisiods will be found in the Amer. Journ. Anat., 

 1912, vol. 13, pp. 477-503.) 



(Esophagus. 



Gastric canal. 

 Angular incisure. 



Fundus. 



Duodenal 

 antrum. 



Corpus. 



FIG. 244. MODEL OF THE GASTRIC EPITHELIUM IN A HUMAN EMBRYO OF 44.3 MM. X 18 diam. 



The inner surface of the stomach presents macroscopic longitudinal 

 folds, which become coarse and prominent as the organ contracts. They 

 are sinuous, and anastomose in an irregular network. As finer markings, 

 there are rounded or polygonal areas, 2-4 mm. in diameter, which may 

 appear as elevations or depressions. They have been ascribed to the con- 

 traction of muscle fibers in the mucous membrane, to varying amounts of 

 lymphoid tissue, and to the varying height of the glands. Toward the 

 pylorus there are small leaf-like elevations, the plica villosce, which may 

 connect with one another in a network. The epithelium of the stomach is 

 thin enough to transmit the color of the underlying tissue, and appears 

 pinkish gray; whereas the color of the oesophagus, with a thicker epithelium, 

 is white. 



The gastric epithelium, like that of the entire intestine, is a single layer 

 of columnar cells. In the stomach the cells are tall and contain mucus, but 

 they do not ordinarily acquire the bulging goblet shape, since the adjacent 

 cells likewise contain mucus. This simple layer of mucous cells is con- 

 tinuous at the cardia with the basal layer of the stratified epithelium of the 



