THE STOMACH AND INTESTINE. 



28 3 



5. BLOOD, LYMPH, AND NERVE SUPPLY OF THE INTESTINE. 



In general, the following holds true with regard to the blood- 

 vessels of the intestinal tract (further details will be discussed in 

 dealing with the vessels of the various regions of the intestine) : 

 The arteries enter along the line of the mesenteric attachment and 

 penetrate the longitudinal muscular layer. Between the two mus- 

 cular layers branches are given off which form an intermuscular 

 plexus, from which, in turn, smaller branches pass out to supply 

 the muscles themselves. The arterial trunks penetrate the circu- 

 lar muscular layer and form an extensive network of larger 

 vessels in the deeper layer of the submucosa. This is known 

 as Heller's plexus (F. P. Mall). From this, radiating branches are 



; Epithelium of 



stomach. 



-- Region of the 

 bodies of the 

 gastric glands. 



Fig. 223. Section through fundus of cat's stomach, 

 injected ; X oo - 



- - Muscularis mucosae. 



The blood-vessels are 



given off which supply the muscularis mucosae, forming under 

 the latter a close network of finer vessels. This plexus, together 

 with that of Heller, gives rise to vessels which penetrate the mus- 

 cularis mucosse and break up into capillaries in the mucous mem- 

 brane. The veins of the mucous membrane form beneath the 

 muscularis mucosae a plexus with small meshes, giving off many 

 radiating branches ; these in turn unite to form an extensive net- 

 work of coarser vessels. Veins extend from the latter and unite 

 to form larger trunks, which then lie side by side with the arteries. 

 According to F. P. Mall, delicate retia mirabilia occur here and 

 there in the venous network in the submucosa of the intestine of 

 the dog. 



In the esophagus the arteries end in a capillary network situated 



