32 



EPITHELIAL TISSUE. 



epithelium is seen in the goblet-cell. This occurs in the intestine, 

 for example ; the mucin, which is the product of the cell, distends 

 the upper part of it, and the cell bursts (Fig. 22). The mucin is 

 discharged as mucus, and the open, cup-like end of the cell gives 

 to it the peculiar appearance characteristic of the goblet-cell. 



Goblet-cell. 



Cilia. 



FIG. 21. Cross-section of stratified ciliated columnar epithelium from the trachea 

 of a rabbit (Huber). 



Formerly regarded as a simple modification of the columnar cell, 

 these goblet-cells are probably more properly to be considered as 

 a special kind of epithelium which is of a permanent nature, and 

 whose function is to secrete mucus ; hence they are sometimes 

 called mucus-secreting cells. 



Spheroidal or Glandular Epithelium. This is charac- 

 terized by its polyhedral or spheroidal shape, and occurs in secreting 



Cilia. 



Mucin. 



Nucleus. 



Basal process - 



FIG. 22. Goblet-cells from the bronchus of a dog : the middle cell still pos- 

 sesses its cilia : that to the right has already emptied its mucous contents (collapsed 

 goblet-cell) ; x 600 (Bohm and Davidoff). 



glands ; as, the salivary glands, liver, and pancreas. The secretion 

 of ^ these glands is the product of the protoplasm of the glandular 

 epithelium. 



Ciliated Epithelium (Fig. 23). The characteristic of this 

 variety is the cilia or hair-like or eyelash-like appendages attached 



