378 DIGESTION 



the oesophagus. Some of the glands are single tubules, but 

 others have two or more tubules opening into a common duct. 

 Both are lined by a single layer of short columnar epithelium, 

 which contains granules. (2) The glands of the pyloric canal 

 or antrum. These consist of short, branched tubules, which open 

 by twos and threes into long ducts. (3) The glands of the 

 fundus or oxyntic glands, occupying the intermediate and greater 

 portion of the organ. The gland tubules are long and seldom 

 branched, and the ducts, into each of which open from one to three 

 tubules, are relatively short. The secreting parts of both kinds of 

 glands are lined by short columnar granular cells; and in the pyloric 

 tubules no others are present. But, as we have said, in the glands 

 of the fundus there are besides large ovoid cells scattered at intervals 

 like beads between the basement membrane and the lining or chief 

 cells. The cells of the pyloric glands have a general resemblance to 

 the chief cells of the fundus glands, but they are not quite the same. 

 For example, the granules are less distinct in the pyloric glands. In 

 the human stomach it is only quite near the pylorus that the parietal 

 cells disappear altogether. The parietal cells also contain granules, 

 but they are smaller and less numerous than those of the chief cells, 

 so that the deeper portions of the fundus glands are much darker in 

 appearance than the more superficial portions, since the oxyntic or 

 parietal cells are more numerous in the neighbourhood of the ducts 

 (Bensley). 



The histological changes connected with gastric secretion do not 

 differ essentially from those described in the pancreas and the 

 parotid, but there is much greater difficulty in making observations 

 on the living, or at least but slightly altered, cells. For the mammal 

 the best method is to use animals with a permanent gastric fistula, 

 and to remove from time to time small portions of the mucous 

 membrane for examination in the fresh condition. During digestion 

 the granules disappear from the outer part of the chief cells of the 

 fundus glands, leaving a clear zone, the lumen being bordered by a 

 granular layer. Or, more rarely, there may be a uniform decrease 

 in the number of granules throughout the cell. The total volume 

 of the cell is less than in the fasting condition. The parietal cells, 

 which are small in the fasting animal, swell up, so as to bulge out the 

 membrana propria. They reach their maximum size (in the dog) 

 very late in digestion (the thirteenth to the fifteenth hour). No 

 such definite changes in their contents as those observed in the other 

 cells have been made out. The granules in the ovoid cells during 

 and after activity seem to be as large and as numerous as in the 

 resting cell, or even larger. After sham feeding in dogs the histo- 

 logical changes in the gastric glands are very slight, even when con- 

 siderable amounts of gastric juice have been secreted (Noll and 

 Sokoloff). 



