THE ALIMENTARY CANAL 



349 



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 dilatations; they possess a 

 characteristic, tortuous form. Their columnar secreting cells have a 

 strong affinity for muchematein and other mucous stains. This basophil 



sm. 



FIG. 326. PHOTOMICROGRAPH OF A TRANSVERSE SECTION THROUGH UPPER THIRD 



OF CAT'S ESOPHAGUS. 



TO, mucosa, consisting of a stratified squamous epithelium, a membrana propria, 

 a tunica propria, and a muscularis mucosse (mm.); sm., submucosa; me., muscular 

 tunic, containing at this level an inner longitudinal layer of striped muscle fibers; 

 /, fibrous tunic. 



reaction, together with the situation of their isolated groups of secreting 

 acini in the submucosa, sharply distinguishes the esophageal mucous 

 glands from the glands of the stomach and intestine, except those of the 

 duodenum. 



The number of the esophageal glands in man is extremely variable. 

 This numerical variability is associated with frequent cyst formation, 

 stasis of secretion, and atrophy of the glandular elements; conditions 

 indicating small functional significance. In certain mammals, e.g., 

 rodents, ox, horse, sheep, cat, and bat, glands are entirely lacking; 



