24 EPITHELIAL TISSUES 



the formation of cilia, is similar to that of the simple non-ciliated 

 columnar cells. Their cytoplasm, as in other types, may con- 

 tain vacuoles, pigment granules, paraplasm, and even secretory 

 granules. 



PYRAMIDAL CELLS" GLANDULAR EPITHELIUM." This 



variety of the columnar cell occurs in the secreting glands. It is, 



perhaps, unnecessary to distinguish it from the simple columnar 



^^ cell, there being but little differ- 



ence in the structure of their 



44ft protoplasm. The peculiar shape 



^ which characterizes these cells re- 



^^ $1 suits from their disposition to 



form the wall of secreting tubules, 

 sacular acini, etc. The greater 

 area of their base as compared 

 with that of their free extremity 



f 



FIG. 23.-A GROUP OF CELLS FROM A 



TRANSECTION OF AN ACINUS OF THE cated pyramid. A cuticular bor- 



HUMAN PANCREAS; GLANDULAR EPI- er j g no ^ usua lly present. The 



THELIUM. ,, . . ,, 



cells are partially or completely 



Hematem and eosin. x ooO. . \ J J 



loaded with secretory granules. 



Pyramidal or glandular epithelium is found in tubules of the 

 kidney, salivary glands, and pancreas, in the secreting glands of 

 the gastric and intestinal mucous membrane, in the mucous glands 

 of the esophagus, pharynx, bronchial tubes, and oral and nasal 

 cavities, and in the secreting glands of the skin. 



GOBLET CELLS. These cells are derivatives of the columnar 

 variety, and may occur among either the plain or ciliated colum- 

 nar cells. Goblet cells are most abundant in the intestinal tract, 

 but are also to be found in the stomach, bronchial tubes, trachea, 

 nasal mucous membrane, and in the ducts and tubules of mucus- 

 secreting glands. In such epithelial membranes certain columnar 

 cells, if not indeed all of these cells, are destined to secrete 

 mucus. The cytoplasm of such cells is converted into a clear, 

 poorly chromatic mass of a peculiar glassy or vitreous appearance, 

 which occupies an increasing proportion of the free extremity of 

 the cell. This "mucinogen" when acted upon -by alcohol, is pre- 

 cipitated within the cell, and then forms fine basophile fibrils or 

 granules, which stain deeply with the muchematein and muci- 

 carmine solutions of P. Mayer. At the base of the goblet cell its 

 nucleus is embedded in a minute mass of unaltered granular cyto- 



