I QO NORMAL HISTOLOGY AND ORGANOGRAPHY. 



tissue elements, largely elastic fibers, connective- 

 tissue cells and fat cells. Nerve cells and nerve 



fibers, known as 

 Meisner's plexus, are 

 found here and in the 

 submucosa through- 

 out the alimentary 

 canal. 



3. Muscularis. 

 This consists of 

 smooth muscle and 

 may be divided into 

 three layers : (a) an 

 inner sheath where 

 the fibers run ob- 

 liquely; this sheath 

 is continuous with 

 the circular layer of 

 the esophagus; (6) 

 a middle circular 

 layer which is con- 

 tinued as the circu- 

 lar layer of the in- 

 testine ; (c) an outer 

 longitudinal layer 

 continuous with the 

 longitudinal layer of 



both esophagus and intestine; nerve cells and 

 nerve fibers form a plexus between the longitudinal 

 and circular muscle of the whole alimentary tract, 

 which is known as the plexus of Auerbach. 



4. Serosa. This consists of a thin layer of fibrous 

 tissue .covered by simple pavement epithelial cells 



Fig. 139. From vertical section 

 through human pylorus (Bohm and 

 Uavidoff). 



