OESOPHAGUS 



249 



laris mucosae into the submucosa, where their blind ends expand and 

 branch, producing a cluster of tubulo-alveolar end pieces. The terminal 

 portions at birth are still poorly developed. The tubules are composed 

 wholly of mucous cells, although the basal protoplasm sometimes simulates 

 crescents. The ducts are slender tubes generally lined with simple epi- 

 thelium. They tend to slant toward the stomach, and they enter the 

 epithelium where it dips down between the connective tissue papillae. The 

 cells of the ducts become continuous with the basal layer of the epithelium. 

 Large ducts are sometimes lined with stratified epithelium, often ciliated, 

 and they may present cyst-like dilatations. Lymphocytes tend to accumu- 



Stratified epithe- 

 lium. 



Tunica propria. 

 ,../ yMuscularis 

 mucosae. 

 Submucosa e. 



Mucous 

 membrane. 



Group of 



fat cells. 



\ 



\ 



\Circular muscles, "j 

 Longitudina mus- >Muscularis. 

 cles. J 



v Tunica adventitia. 

 'Mucous gland. 



Lymph nodule. 

 FIG. 242. TRANSVERSE SECTION OF THE UPPER THIRD OF THE HUMAN (ESOPHAGUS. 



X s- 



late around the ducts and occasionally they form nodules in the tunica 

 propria. The glands may show signs of infiltration and degeneration. 

 The number of deep glands varies greatly in different individuals. They 

 are usually more numerous in the upper half of the oesophagus. 



The superficial glands (glandula cesophagea superficiales] are limited 

 to two rather narrow zones near the ends of the oesophagus. They are 

 always found at the entrance of the stomach, extending from i to 4 mm. 

 up the oesophagus; and generally (in 70% of the cases examined by Schaffer) 

 they occur between the level of the cricoid cartilage and fifth tracheal 

 ring. They develop in the embryo much earlier than the deep glands, 

 and appear as small areas of tall mucous cells which pass clear through 

 the stratified epithelium. The is eslandsof simple epithelium become 

 depressed into shallow pockets from which a cluster of tubules grows 



