ESOPHAGUS 275 



The fibrous septum between the muscular layers contains the 

 larger blood vessels and the nerve plexus of Auerbach. 



THE SUBMTJCOUS COAT forms a layer of areolar connective 

 tissue which firmly unites the muscular and the mucous coats. 

 It contains those blood and lymphatic vessels, together with the 

 nerve plexus of Meissner, whose branches supply the mucous 

 membrane. It also contains a considerable number of tubulo- 

 acinar mucous glands whose ducts enter the mucous membrane 

 and open upon the free epithelial surface. The secreting acini of 

 these glands are short branching tubules with ampullary dilata- 

 tions ; they possess a characteristic, tortuous form. Their col- 

 umnar secreting cells have a strong affinity for muchematein and 

 other mucous stains. This basophile reaction, together with the 

 situation of their isolated groups of secreting acini within the 

 submucosa, sharply distinguishes the esophageal mucous glands 

 from the secreting glands of the stomach and intestine. 



THE MUCOUS COAT (mucosa) of the esophagus consists of a 

 tunica propria or corium of areolar tissue which rests upon a well- 

 developed muscularis mucosae and is covered on its free surface by 

 stratified squamous epithelium. 



The muscularis mucosae contains considerable bundles of smooth 

 muscle whose general direction is a longitudinal one in its outer, 

 and circular in its inner portion. This layer forms tho outermost 

 layer of the mucous coat, and is penetrated by the ducts of the 

 deep mucous glands whose secreting acini lie in the submucosa. 



The inner portion of the tunica propria carries on its surface 

 many tall connective tissue papillae which project well into the 

 epithelial coat and which closely resemble the vascular papillae of 

 the skin. 



The mid-portion of the corium is penetrated by the ducts of 

 the mucous glands. These are at first lined by low columnar cells 

 which, as they approach the epithelial surface are changed into 

 several layers of flattened cells, which thus form a thin stratified 

 lining, continuous with the superficial stratified squamous epithe- 

 lium of the esophageal mucosa. Many of these ducts possess 

 small cystic dilatations which are found in the connective tissue 

 of the corium or occasionally in the submucosa. 



Superficial Glands. At about the level of the cricoid cartilage 

 the esophageal mucous membrane presents two lozenge-shaped 

 depressions, one on either side, whose diameter varies from 1 cm. 

 down to a microscopical size. These areas mark the site of the 



