COATS OF THE STOMACH. 



193 



of columnar epithelium, which secretes the mucus found in the 

 stomach in the intervals of digestion, this mucus being a con- 

 stituent of the gastric juice. 



In the mucous membrane, and forming a part of it, are two 

 sets of glands, the pyloric glands, so called from their abundance 

 in the pyloric portion of the stomach, and the cardiac glands 

 (Fig. 107), which are so called because of their occurrence in the 

 cardiac region. The pyloric glands were formerly called mucous 

 glands, but their product is not mucus ; the cells are of the serous 

 type described in connection with the salivary glands. The ducts 

 of both cardiac and pyloric glands are lined by columnar epithe- 





FIG. 107. Cardiac glands. Diagram showing the relation of the ultimate 

 twigs of the blood-vessels (V and A), and of the absorbent radicals (L) to the 

 glands of the stomach, and the different kinds of epithelium namely, above, 

 cylindrical cells ; small pale cells in the lumen ; outside which are the dark ovoid 

 cells. 



lium continuous with that covering the mucous membrane. In 

 the tubes of the pyloric glands are granular cells called chief or 

 central cells. The same kind of cells are found in the tubes of the 

 cardiac glands ; and beneath these cells that is, between them and 

 the basement-membrane are, besides, large cells, which are ovoid 

 in shape, the parietal or oxyntic cells. These cells cause the base- 

 ment-membrane against which they lie to bulge out. The chief 

 cells are regarded as producing the pepsinogen which is converted 

 into the pepsin of the gastric juice, and the parietal cells as pro- 

 ducing the hydrochloric acid, although the latter has not been 

 certainly demonstrated. The vascularity of the stomach is very 

 great. In the intervals of digestion the mucous membrane is of a 



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