THE STRUCTURE OF THE GASTRIC MUCOUS MEMBRANE. 



289 



diminishes intestinal peristalsis through irritation of the splanchnic nerve. (3) 

 Other drugs stimulate the motor apparatus; such as nicotin, to the point of 

 intestinal cramps, muscarin, caffein and some laxatives, which thus act as evacu- 

 ants. The movement excited by muscarin can be neutralized by atropin. As, 

 in consequence of the rapid movement of the intestinal contents, the contained 

 fluid can be absorbed in but small measure, the frequent evacuations that follow 

 are at the same time liquid. (4) Among purgatives, mention should be made 

 of those that irritate the intestines directly, such as colocynth and croton-oil. It 

 is supposed that agents of this kind cause a watery transudation from the blood- 

 vessels into the intestine, just as croton-oil also causes vesicles on the external 

 skin. (5) Certain laxative salts, sodium sulphate, magnesium sulphate and others, 

 liquefy the intestinal contents by retaining for their solution in the intestine the 

 water of the intestinal contents; if, therefore, they are injected into the blood- 

 vessels of an animal, constipation may even result. (6) Calomel (mercurous 

 chlorid) restricts the absorptive power of the walls of the intestine, and also 

 putrefactive decomposition in the bowels. Therefore the fecal evacuations are 

 thin, with little odor, and of a greenish color from admixture of unchanged bili- 

 verdin. 



THE STRUCTURE OF THE GASTRIC MUCOUS MEMBRANE. 



The surface of the mucous membrane of the stomach exhibits numerous small 

 depressions, the gastric crypts (foveolae gastricae, Fig. no), lined by a single 

 layer of mucous goblet cells (Fig. 112, d). These cells are sharply delimited 

 at the cardiac orifice from the stratified squamous epithelium of the esophagus; 

 and at the pyloric extremity from the true cylindrical epithelium of the 

 duodenum. The cells with almost homogeneous contents are provided with 

 elliptical nuclei containing nucleoli. Between their narrowed, lower ends are 

 scattered oblong or spindle-shaped, unencapsulated, nucleated elements, exhibiting 

 mitosis, which are intended to replace desquamated cells. All cells are completely 

 open upon their free surface, so that 

 nothing prevents the escape of the mucus 

 elaborated by mucous metamorposis from 

 the cell-protoplasm. The simple tubular 

 gastric glands, generally several in num- 

 ber, empty into the bottom of the gastric 

 crypts. They occur in two different 

 forms : 



1 . As true gastric glands, peptic glands 

 of the fundus (Fig. 114), which number 

 about five millions, the largest being 

 present in the fundus. The structureless 

 membrana propria of simple tubular form, 

 has, on its internal surface, two different 

 kinds of cells : (a) the chief cells (Fig. in, 

 II, a), the adelomorphous ceils of Rollett; 

 small, unencapsulated, nucleated, ^pale 

 cells lying close together, lining the inner 

 lumen of the glands, and (b) larger, 

 mainly scattered, plainly projecting parie- 

 tal cells (Fig. in, II, h), the delomorphous 

 cells of Rollett, ovoid or crescentic, without 

 a membrane, darkly granular, readily 

 stained with osmic acid and aniline-blue, 

 containing, at times, several nuclei. They 

 cause bulbous projections of the mem- 

 brana propria. In human beings the 

 parietal cells are thought to reach to the 



lumen of the spaces within the gland. They are even found scattered under the 

 epithelium of the crypts and the surface of the mucous membrane, as well as i 

 isolated pyloric glands. Between the chief cells secretory spaces are present, and 

 likewise between neighboring parietal cells, while, at the same time, with the latter 

 delicate branching and anastomosing passages in part lead from the excrete 

 duct of the gland into the interior of the parietal cells and in part form a network 

 surrounding them. 



2. Only in the vicinity of the pylorus, where the mucous membrane has a 



FIG. no. Sectional View of the Gastric Mucous 

 Membrane, Showing the Crater-like Depres- 

 sions of the Gastric Crypts: a, a, the most 

 prominent projections of the mucous mem- 

 brane (from a dog). 



