DIGESTION. 



165 



This is strengthened by fibrous tissue and embraced by the sphincter muscle 

 previously described. 



Gastric Glands. The surface of the mucous membrane when examined 

 with a low magnifying power presents throughout innumerable depressions 

 polygonal in shape and separated by slightly elevated ridges. At the bottom 

 of these spaces are to be seen small orifices, which are the mouths of the 

 glands embedded in the mucous membrane. A vertical section of the 

 gastric walls shows not only the position and the appearance of the 

 glands, but the relation of the various tissues which enter into the formation 

 of these walls. An examination of the mucous membrane in different 

 regions of the stomach reveals the presence of two 

 distinct types of glands, which from their situation are 

 termed preantral or cardiac, and pyloric, which differ 

 not only in histologic structure, but also in function. 

 Both types extend through the entire thickness of the 

 mucosa. 



The preantral or cardiac glands are formed by an 

 involution of the basement membrane of the mucosa 

 and lined by epithelial cells. Each gland may be said 

 to consist of a short duct, or neck, and a body, or fun- 

 dus (Fig. 72). The latter portion is wavy or tortuous 

 and frequently subdivided into as many as four dis- 



Vo \ 



Lumen. 



FIG. 72. PREANTRAL 

 OR CARDIAC GLAND, m 

 Mouth of the duct; n, neck; 

 /. fundus; c, central cells; 

 p, parietal cells. (Landois 

 and Stirling.) 



FIG. 73. SECTION OF FUNDUS GLAND 

 OF MOUSE. Left upper half drawn after 

 an alcohol preparation, right upper half 

 after a Golgi preparation. The entire 

 lower portion is a diagrammatic combi- 

 nation of both preparations. (Stdhr.) 



tinct and separate tubules. The duct is lined by columnar epithelial cells 

 similar to those covering the surface of the mucosa. The lumen of the 

 gland is bordered by epithelial cells, cuboid in shape, and consisting of a 

 granular protoplasm containing a distinct spherical nucleus. These cells 

 are generally spoken of as the chief or central cells. In addition to the 

 chief cells, the preantral or cardiac glands contain a second variety of 

 cell, which is of a larger size, of a triangular or oval shape, and consisting of a 

 finely granular protoplasm. From their situation in and just beneath the 

 gland wall they have been termed parietal or border cells. Each parietal 



