38 



HISTOLOGY. 



In cylindrical epithelium, on the contrary, the height 

 exceeds the two other dimensions of the cell. The cells of 

 cylindrical epithelium have the form of more or less long 

 polygonal prisms or pyramids. The nucleus may be in the 



FIG. 21. 



Flat epithelial cells isolated from the oral mucous membrane of man. X 375. 



middle or at either end of the cell. The centrosome lies in the 

 protoplasm between the nucleus and the free surface of the 

 cell, and holds often a quite superficial position. It usually is 

 present in the form of a single or double granule. 



FIG. 22. 



Impression made by 

 neighboring cell 



**** 



Cell body 



Nucleus 



Two ciliated cells and two goblet cells isolated from the frog's oesophagus, x 520. 



Between the flat and the higher epithelial cells there are 

 transition forms. When all three dimensions are equal, we call 

 them cubical epithelial cells. 



Cylindrical epithelium may undergo certain modifications. 



