HISTOLOGY 117 



thickness. The lamina propria is composed of fibrous connective tissue 

 and does not form papillae. The mucous membrane forms longitudinal 

 folds. The muscularis mucosae is developed only in the lower, caudal third 

 while in the upper two thirds the lamina propria is continuous with the loose 

 connective tissue of the submucosa. The muscularis externa is composed 

 of striated muscle fibers throughout the entire length of the tube to the 



Cardiac antrum 



Region of pyloric glands 



Region of gastric glands 



Esophagus 



Right Jf-H-v-^rr "f V^^r''/ A ^*'* 



Non-glandular part 



Ridge 



Fig. 53. — Stomach, outline drawing. 



cardiac opening of the stomach. The outer surface of the esophagus is 

 attached by a layer of loose connective tissue, the tunica adventitia. No 

 glands are present (39). 



Stomach. — The esophagus enters the stomach in about the middle of the 

 lesser curvature. Grossly the stomach shows two parts, the thin-walled, 

 slightly transparent, grayish part on the left, and the thick-walled, white 

 part on the right. The mucous membrane of the former is devoid of glands, 

 while the latter contains the digestive glands (Fig. 53). Since the wall of 

 the stomach distends and stretches easily, the size relationship of the two 

 parts is not always the same but depends on the amount of food present 

 in each. The lining of the glandless part is a stratified cornified squamous 

 epithelium similar to the lining of the esophagus. The lamina propria 

 forms numerous papillae. At the boundary of the non-glandular and 

 glandular part the mucous membrane of the former forms a ridge. This 

 ridge is particular!}' prominent dextral to the entrance of the esophagus, 

 there forming a channel-like extension of the non-glandular part, the cardiac 



