SIMPLE EPITHELIUM 27 



Simple Non-ciliated Columnar Epithelium, figure 23, lines, a, the mucous 

 membrane of the stomach and intestines as a single layer, from the cardiac 

 orifice of the stomach to the anus, and b, wholly or in part all the ducts of the 

 glands opening on its free surface, and c, many gland ducts in other regions 

 of the body, e.g., mammary, salivary, etc. The intracellular and intra- 



FiG. 22. Peritoneal Surface of a Portion of the Septum of the great Lymph Sac of Frog. 

 The stomata, some of which are open, some collapsed, are surrounded by endothelial cells 

 Klein.) X 160. 



nuclear networks are well developed, and in some cases the spongioplasm is 

 arranged in rods or longitudinal striae at one part of the cell, as in the cells of 

 the ducts of salivary glands. The protoplasm of columnar cells may be 

 vacuolated and may also contain fat or other substances seen in the form of 

 granules. Certain columnar cells transform a large part of their protoplasm 



FIG. 23. Simple Columnar Epithelial Cells from the Human Intestinal Mucous 

 Membrane, a, Mucous (goblet) cell; b, basement membrane; c, cuticle; d, leucocyte 

 nucleus; e, germinating cell. (Bailey.) 



into mucin, goblet cells, figure 24, which is discharged by the open mouth 

 of the goblet, leaving only a nucleus surrounded by the remains of the proto- 

 plasm in its narrow stem. This transformation is a normal process which 

 is continually going on during life, the cells themselves being supposed to 

 regenerate into their original shape. 



Stratified Epithelium. The term stratified epithelium is employed 



