140 



THE ESSENTIALS OF HISTOLOGY 



are two layers of the muscular coat, an outer layer, in which the fibres 

 run longitudinally, and an inner, in which they course circularly. The 

 mucous membrane is lined by a stratified epithelium, into which micro- 

 scopic papillae from the corium project. The corium is formed of areolar 

 tissue, and its limits are marked externally by a narrow layer of longi- 



FIG. 172. SECTION OF THE HUMAN OESOPHAGUS. 



The section is transverse, and from near the middle of the gullet, a, fibrous covering ; 

 6, divided fibres of the longitudinal muscular coat ; c, transverse muscular fibres ; d, sub- 

 mucous or areolar layer ; e, muscularis mucosae ; /, papillae of mucous membrane ; g, lami- 

 nated epithelial lining ; h, mucous gland ; i, gland duct. 



tudinally disposed plain muscular fibres, the muscularis mucosa. This 

 is separated from the proper muscular coat by the areolar coat, which 

 contains the larger branches of the blood-vessels and lymphatics, and 

 also most of the mucous glands of the membrane. 



