C. THE OESOPHAGUS, BY E. KLEIN. 539 



The external muscular coat consists generally of an internal circular 

 and an external longitudinal layer. Fasciculi of fibrous tissue of 

 various size, given off from the fibrous sheath investing the muscular 

 coat externally, penetrate between the muscular fasciculi, forming thin 

 septa, and constituting the support of the larger vessels and nerves as 

 well as of the capillaries and the smallest nervous twigs. 



Before we pass to the consideration of the histology of the 

 stomach we must investigate the mode of transition of the 

 several layers of the oesophagus into those of the cardia. In 

 the oesophagus of man the laminated pavement epithelium ex- 

 tends to the cardia, where it ceases with a dentated border, and 

 is replaced by a columnar epithelium. The mucous layer in its 

 more restricted sense becomes rapidly thicker, in consequence 

 of the additional series of glands that here make their appear- 

 ance ; so that the muscular layer of the mucous membrane 

 becomes constantly separated by a greater distance from the 

 epithelium, and at the same time diminishes in thickness. 



The submucous tissue in general diminishes in thickness at 

 the cardia, and is divisible into an internal looser and an external 

 more compact layer. In the former lie the great vessels, whilst 

 the fasciculi of the latter penetrate between the fasciculi of the 

 muscularis externa. 



There are no acinous glands immediately above the cardia. 



The external muscular layer shows the most important 

 changes ; the circular muscular fibres which are directly con- 

 tinuous with those of the cardia are most strongly developed 

 just above it ; at the cardia itself, and just below it, they again 

 diminish in thickness. The disposition of the longitudinal 

 fibres is similar, except that their fasciculi frequently decussate 

 so that they form a dense plexus. At the same time, after as- 

 suming this plexiform arrangement, some of them extend into 

 the circular muscular layer, surrounding its most external fasci- 

 culi in order to become still more internal at a lower point. 

 According to Henle,* the longitudinal fibres of the oesophagus 

 partly terminate at the cardia, but the majority are distributed 

 upon the stomach, diverging from one another in various 



Henle, Splanchnologie, p. 161. 



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