HISTOLOGY 



119 



lined by simple columnar cells which do not show special secretory granules. 

 Bensley (7, 8) considered these as cardiac glands. 



The gastric glands have a fairly straight course and open into short 

 gastric pits. The cells which are most numerous in the lower third of the 

 tubules are the serous chief cells or zymogenic cells. They are columnar 

 cells having large oval nuclei, situated at the center, and granular cytoplasm. 





•-A 





4 





'Epithelium 



-Villus 



Lamina propria 



glands 



Circular muscle 

 layer 



Longitudinal muscle 

 layer 



■ Serosa 



Fig. 55. — -Duodenum, longitudinal section. (X200.) 



In stained preparations the cells show basophilic granules above and basal 

 striated chromophil substance below the nuclei. Mitotic division cannot be 

 found among these cells. In the upper part of the tubules and in the neck 

 there are cells which are similar in structure but contain lighter staining 

 cytoplasmic granules and slightly compressed nuclei. These are the mucous 

 neck cells. Mitoses occur occasionally among these cells. Scattered among 

 the serous chief and mucous neck cells but occurring in particularly large 

 numbers in the upper part of the tubules are the parietal cells which are 

 large, round or wedge-shaped cells with clear acidophilic cytoplasm. The 



