18 THE STRUCTURE OF THE GLANDS OF BRUNNER 



lamina muscularis mucosse smooth muscular fibers radiate into the connective tissue of 

 the tela submucosa, forming a more or less perfect network around the glandular lobules. 

 In the mucous membrane the intestinal epithelium and glands begin just beyond the 

 pyloric sphincter, there being as a rule very little intermingling of intestinal and gas- 

 tric elements, although for a short distance ( 8 mm. ) a few pyloric glands, serving as 

 ducts for the superficial glands of Brunner, could be discerned. 



The lobules are composed of branching tubules of large diameter and lined by 

 large secretion- filled epithelial cells. Each lobule is provided with a duct, often of 

 extraordinary size, which penetrates the lamina muscularis mucosse, often presenting 

 at this point an ampulla-like dilatation, extends through the mucous membrane a vari- 

 able distance, and terminates in a shorter or longer gland of Lieberkuhn. Rarely 

 these ducts reach the free surface without being intercepted by a gland of Lieberkuhn. 

 A minority of the ducts open into the bottoms of the intestinal glands, directly after 

 having passed through the lamina muscularis mucosaB. The majority extend about 

 half the thickness of the mucous membrane, become abruptly reduced in size, and are 

 continued to the surface by a gland of Lieberkuhn. A few reach the surface without 

 alteration in the type of epithelial cells. Whenever the ducts open into a gland of 

 Lieberkuhn, the change of epithelium is abrupt. 



The cells of the glands of Brunner from the single individual available for exami- 

 nation resembled the secretion-filled stage of the opossum's glands. They were from 

 16 M to 22 /* in height and filled with secretion. In iron hsematoxylin preparations the 

 cell exhibited a delicate network with very large meshes, the nucleus being crowded 

 off into one of the basal angles of the cell. A peculiarity of the nuclei in these cells 

 was that, instead of occupying the middle of the base of the cells, they were in one 

 corner and flattened parallel to the lateral walls of the cells. Otherwise the condition 

 was the same as in other secretion-filled mucous cells. In strong muchcematein solu- 

 tions the cells stained intensely and showed a very coarse network of blue-stained 

 trabeculce. 



No trace of a division of the secretion into two masses was discernible in the 

 cells of the gland tubules, but those of the ducts exhibited a distinct transverse band 

 of cytoplasm, so dividing the secretion. 



The resemblance between the cells of the glands of Brunner and those of the 

 pyloric glands in the raccoon is very close, the only character in which a difference 

 could be made out being the subdivision of the secretion into two masses, which was 

 obvious in the pyloric glands, but in the glands of Brunner visible only in the cells of 

 the ducts. 



In the mink (Lutreola vison), the glands of Brunner are confined to the submu- 

 cosa and form a compact mass, beginning opposite the pyloric sphincter about 1 mm. 

 beyond the point of greatest thickness of the latter, and extending a distance of about 

 12 mm. into the duodenum. The glands are composed of more or less rounded lobules 

 closely packed together in the submucosa 1 , which they almost fill from the lamina 



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