DIGESTION. 



249 



() Pyloric Glands. These glands (Fig. 187), have much longer 

 ducts than the peptic glands. Into each duct two or three tubes open 

 by very short and narrow necks, and the body of each tube is branched, 

 wavy, and convoluted. The lumen is very large. The ducts are lined 

 with columnar epithelium, and the neck and body with shorter and 

 more granular cubical cells, which correspond with the central cells of 

 the peptic glands. During secretion the cells become, as in the case of 

 the peptic glands, larger, and the granules restricted to the inner zone 

 of the cell. As they approach the duodenum the pyloric glands become 

 larger, more convoluted, and more deeply situated. They are directly 

 continuous with Brunner's glands in the duodenum. (Watney.) 



mm. 



FIG 187. 



FIG. 188. 



FIG. 187. Section showing the pyloric glands, s, free surface; d, ducts of pyloric glands; w, 

 neck of same; m, the gland alveoli; mm, muscularis mucosae. (Klein and Noble Smith.) 



FIG. 188. Plan of the blood-vessels of the stomach, as they would be seen in a vertical section, 

 a, arteries, passing up from the vessels of submucous coat; 6, capillaries branching between and 

 around the tubes; c, superficial plexus of capillaries occupying the ridges of the mucous membrane; 

 d. veins formed by the union of veins which, having collected the blood of the superficial capillary 

 plexus, are seen passing down between the tubes. (Brinton.) 



Changes in the gland cells during secretion, The chief or cubical 

 cells of the peptic glands, and the corresponding cells of the pyloric 

 glands during the early stage of digestion, if hardened in alcohol, appear 

 swollen and granular, and stain readily. At a later stage the cells be- 

 come smaller, but more granular and stain even more readily. The 

 parietal cells swell up, but are otherwise not altered during digestion. 

 The granules, however, in the alcohol-hardened specimen, are believed 

 not fco exist in the living cells, but to have been precipitated by the hard- 



