THE PHARYNX AND ESOPHAGUS. 



263 



are lined for the greater part by a single layer of columnar cells ; 

 at their termination they often possess a lining of stratified pave- 

 ment epithelium. (2) The other variety of glands are found in two 

 zones, the one situated at the upper end of the esophagus, in a 

 region opposite the cricoid cartilage to the fifth tracheal cartilage 

 (superficial glands of esophagus, Hewlett; upper cardiac gland, 

 Schaffer), the other at the end of the esophagus, just before it enters 

 the stomach the esophageal cardiac glands. These glands are 

 situated above the muscularis mucosae, and are of the branched 



** Epithelium. 



-"" Mucosa. 

 9""* Muscularis 



Circular layer 

 of muscle. 



c lelayer - 



Outer connec- 

 tive-tissue 

 coat. 



Fig. 205. Section of esophagus of dog; X 1 &- 



tubular variety. The ducts of these glands, which reach the 

 surface through the apices of the connective tissue papillae, are 

 lined by a single layer of columnar epithelial cells. The secreting 

 portions of the tubules are lined by shorter columnar cells. Here 

 and there cells like the parietal cells of the fundus glands of the 

 stomach, to be described later, are also found, as also cells showing 

 a mucous secretion. The cardiac glands of the esophagus are 

 similar to the glands of the same name found at the cardiac end 

 of the stomach, with which they may be said to be continuous, and 

 which will receive further consideration. 



