THE ALIMENTARY CANAL 



351 



tions which are found in the connective tissue of the coriuin or occa- 

 sionally in the submucosa. 



SUPERFICIAL GLANDS. At about the level of the crieoid cartilage 

 the esophageal mucous membrane presents two lozenge-shaped depres- 

 sions, one on either side, whose diameter varies from 1 centimeter down 

 to microscopical size. These areas mark the site of the sii/x'r/irinl 

 glands of the esophagus (Hewlett) or upper cardiac glands (Schafer). 

 These are short 

 branched tubular 

 glands which closely 

 resemble those of the 

 cardiac region of the 

 stomach. They are 

 confined to the mu- 

 cous membrane; 

 their tubules, in 

 marked contrast to 

 those of the deep 

 mucous glands of the 

 esophagus, never 

 penetrating the mus- 

 cularis m u c o s as, 

 which, however, is 

 considerably thinned 

 beneath the superfi- 

 cial glands. These 



a, esophageal epithelium; b, superficial glands; c, mu- 

 cous glands; d, tunica propria; e, muscularis mucosse. 

 Hematoxylin and eosin. Photo. X 17. (After Hew- 

 lett.) 



FIG. 328. FROM A SECTION OF THE SUPERFICIAL GLANDS 

 OF THE HUMAN ESOPHAGUS. 



glands secrete a mu- 



cinous fluid, but 



their cells are not so 



strongly basophilic as 



those of true mucous glands such as the deep glands of the esophagus. 



The ducts of the superficial glands, as well as their secreting portions, 



and also the lining epithelium of the esophagus upon which they open, 



are clothed with columnar epithelial cells. Many of the secreting tubules 



contain parietal cells similar to those of the fundus glands of the stomach. 



Both ducts and secreting tubules contain small, cystic dilatations. 



At the lower end of the esophagus a similar group of superficial 

 glands, the lower cardiac glands of the esophagus. frequently mark the 

 beginning transition to the structure of the cardiac portion of the 

 stomach, with whose glands they are continuous. 



