NORMAL HISTOLOGY. 



conspicuous as longitudinal plications, particularly at the pyloric end and 

 along the greater curvature. The surface of the gastric mucous membrane 

 is divided into small, slightly raised, polygonal areas or mammilla. The 

 latter, from 1-4 mm. in diameter, are stippled with closely placed micro-, 

 scopic pits, the gastric crypts, into which open groups of the individual 

 gland-tubes. The crypts are particularly wide (.2 mm.) in the pyloric 

 region, where they reduce the intervening tissue to mere ridges which in 

 section appear as villous projections ( plica villosa}. 

 The epithelium covering the free surface of the 

 mucosa is a single layer of tall columnar cells (20-30^ 

 high), many of which are engaged in secreting mucus 

 and consequently appear as goblet-cells. Where the 

 oesophagus joins the stomach, the opaque stratified 

 squamous epithelium of the gullet abruptly changes 

 into the transparent columnar gastric cells. The line 

 of transition is zigzag and well defined, the pale cesoph- 

 ageal mucous membrane contrasting with the reddish- 

 gray gastric lining. The unusual thickness of the mu- 

 cosa at the pylorus is in part due to the depth of the de- 

 pressions, the gastric crypts, into which the glands open. 

 The tunica propria consists of a delicate con- 

 nective tissue framework, composed of fibrous and 

 reticular tissue and elastic fibres, supporting many 

 lymphocytes 'and intermingled with strands of invol- 

 untary muscle and capillaries. This stroma resembles 

 loose lymphoid tissue and, where the gastric glands 

 are closely placed, is reduced to the septa and envel- 

 opes which separate and invest the deeper parts of the 

 gastric glands. The latter, here and there, are so 

 surrounded by aggregations of lymphocytes that the 

 stroma assumes the appearance of lymphoid tissue. 

 In the vicinity of the pylorus and sometimes of the 

 cardia, more definite accumulations of such tissue occur 

 in the form of small lymph-nodules (Fig. 200), the 

 so-called ' ' lenticular glands. ' ' Occasionally they are 

 of sufficient size to reach almost the free surface, 

 although commonly they are limited to the deeper parts 

 of the mucous membrane. The muscularis mucosa, as 

 in other parts of the intestinal tube, consists of a thin 

 but well-marked layer of involuntary muscle within 

 the tunica propria next the submucous coat. Two 

 strata are usually distinguishable, an inner circular 

 and an outer longitudinal. Delicate strands of muscle- 

 cells extend between the gastric glands, in places penetrating almost as far 

 as the epithelium. 



The gastric glands comprise two principal varieties, the fundus and 

 the Pyloric glands. The former occur throughout the greater part of the 

 stomach, including the fundus, the anterior and the posterior walls and the 

 curvatures ; the latter are limited, in a general way, to the pyloric canal. An 

 additional variety, the cardiac glands, is represented by a narrow granular 

 group at the oesophageal orifice. 



The fundus glands the gastric glands proper are closely set tubules, 

 single or slightly branched and usually somewhat wavy, which extend almost 



FIG. 197. Gastric glands 

 from fundus-end of stom- 

 ach ; a, opening on sur- 

 face ; 6, neck ; c, funjjus ; 

 d, parietal cells ; e, chief 

 cells. X 105. 



