NON-STKATIFIED EPITHELIA 



41 



structurally expressed in segregation of the presecretion bodies (gran- 

 ules, rods, threads) in the basal end of the cell, and of the secretion 

 products (granules, spherules, and mucous or serous fluid) in the distal 

 end (Fig. 35). Morphologically it represents simply a modified colum- 

 nar cell, its pyramidal shape resulting from mechanical factors due to 

 its disposition in saccular or spherical acini, the periphery of the cen- 

 tral lumen of which is much less than the periphery of the acinus, 

 necessitating the modification in shape of the individual cells (Fig. 46). 

 The cells of glandular epithelium usually lack cuticular borders. Pyram- 

 idal or glandular epithelium is found in tubules of the kidney, salivary 

 glands, the 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. 



(3) Goblet Cell Epithelium. A 

 further important and very widespread 

 modification of columnar cells in epi- 

 thelia concerns the elaboration and 

 storage of mucous secretion, giving to 

 the loaded cells a goblet form (Figs. 47 

 and 48 ) . Goblet cells may occur among 



either the plain or ciliated columnar cells. They 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 glairy mass of a peculiar vitre- 

 ous appearance, which occupies an increasing proportion of the free ex- 

 tremity of the cell. This 'mucinogen/ when acted upon by alcohol, is 

 precipitated within the cell, and then forms fine basophilic fibrils or gran- 

 ules which stain deeply with the muchematein and mucicarmin solutions 

 of P. Mayer. At the base of the goblet cell, its nucleus is embedded in a 

 minute mass of unaltered granular cytoplasm. 



The accumulation of mucus (mucinogen) within the cytoplasm ex- 

 pands the cell, finally ruptures its wall in the direction of least resistance, 

 and thus permits its mucous content to exude upon the free surface, 

 leaving behind the small granular protoplasmic cell remnant attached to 



FIG. 46. A GROUP OF CELLS FROM 

 A TRANSECTION OF AN ACINUS OF 

 THE HUMAN PANCREAS; GLANDU- 

 LAR EPITHELIUM. 

 Hematein and eosin. X 550. 



