284 THE DIGESTIVE SYSTEM 



cific stains for mucus. The nuclei are flattened against the base 

 of the cell and thus contrast sharply with the spheroidal nuclei 

 of the ducts and crypts. 



During secretion the cells become shrunken and their nuclei 

 approach the center of the cell and become more nearly ovoid or 

 spheroidal in shape. 



There is no sharp demarcation between the fundus and pyloric 

 regions, the glands offering a gradual transition from the one type 

 to the other. Thus, in the human stomach, there is a broad tran- 

 sition zone which contains both fundus and pyloric glands. In- 

 deed, in many individuals, parietal cells may be distributed 

 throughout almost the entire gastric mucosa. 



The Cardiac Glands. A narrow region at the cardiac orifice of 

 the human stomach contains glands whose form corresponds with 

 that of the fundus glands, though they are slightly more branched 

 and are rather more tortuous, but which are lined by relatively 

 clear columnar epithelium. Only occasionally are the chief and 

 the parietal cells, which are characteristic of the fundus glands, 

 interspersed among the clear secreting cells of these tubules. The 

 cardiac glands, therefore, appear to offer a transition from the 

 esophageal to the more numerous fundus glands of the stomach. 

 In certain mammals, e. g., the pig and the marsupials, the cardiac 

 glands occupy a much larger area. 



The Corium of the mucosa consists of a delicate fibro-reticular 

 connective tissue which supports the blood and lymphatic ves- 

 sels and is more or less infiltrated with lymphatic corpuscles. 

 Hence in many portions it possesses the character of diffuse lym- 

 phoid tissue, though this tissue is characteristic of the intergland- 

 ular, rather than the interfoveolar, portion of the tunica propria. 

 In the latter situation, in sharp contrast to the intestinal villi, 

 with which the student readily confounds this region, the corium 

 is decidedly fibrous and contains relatively few lymphatic cor- 

 puscles. 



In the deeper part of the mucosa occasional small lymphoid 

 nodules, homologues of the solitary follicles of the intestine, are 

 seen. These nodules* lie just within the muscularis mucosae and 

 do not, as a rule, penetrate into the submucosa. In the cardiac 

 region they may lie very near the free surface of the mucosa. 



* The name, lenticular glands, formerly applied to these lymphatic nqdules, 

 is misleading and should be discarded. 



