156 ELEMENTARY HISTOLOGY 



bloodvessels. Their structure is most readily made 

 out in specimens in which the bloodvessels have 

 been injected with a coloured substance to make 

 them more distinct. 



III. Gastric Glands. The glands of the stomach are well 

 adapted for a more minute examination of the histology of 

 glands. 



Examine again with a high power l/te section of llie, cardiac end 

 of the dog's stomach already used for columnar epithelium. 



1. Characters of the glands. The gastric glands are good 



examples of simple or slightly branched tubular glands. 

 They are deep, but very narrow, cylindrical pits, 

 imbedded vertically in the wall of the stomach, with 

 their open mouths discharging into its cavity. The 

 glands are lined by epithelial cells, and are set very 

 close together side by side. In the microscopical 

 sections, some of the glands may be seen cut along 

 their entire length ; but in most cases, owing to the 

 glands being not quite straight, or the plane of section 

 being oblique to the surface of the stomach, the tubes 

 will be cut more or less obliquely, or even trans- 

 versely. 



2. Characters of the gland cells. There are three distinct 



kinds of epithelial cells found at different parts of 

 the length of the gland. 



i. Columnar cells, arranged in a somewhat radiate 

 manner round the mouths of the glands, and 

 extending a short way down the tubes. 



ii. Cubic cells, or peptic cells, lining the deeper parts 

 of the glands and the greater part of their length : 

 theso are cubical granular cells with centrally 

 placed nuclei. 



iii. Ovoid cells : large oval cells with large nuclei : 

 these are less numerous than the other two forms, 

 and occur most abundantly a short way below the 

 mouths of the glands. They lie along the sidas of 

 each gland, outside the cubical cells, and are said 

 to secrete the acid of the gastric juice. 



