1628 



HUMAN ANATOMY. 



Pyloric ring 



tubules with a close mesh-work. Somewhat larger capillaries constitute a superficial 

 plexus beneath the epithelium encircling the orifices of the gastric crypts. The 

 veins, relatively wide, begin in the subepithelial capillary net-work and traverse the 

 gland-layer, between which and 



the muscularis mucosae they form Fig. 1380. 



a plexus ; from the latter radicles 

 pass into the submucous coat, in 

 which the venous trunks run paral- 

 lel with the arteries, but lie nearer 

 the mucosa (Mallj. The emerging 

 tributaries are often provided with 

 valves at their junction with the 

 larger gastric veins. 



The lymphatics originate 

 within the mucous membrane, be- 

 neath the epithelium, as wide, ir- 

 regular capillary channels which 

 freely communicate with one an- 

 other and pass between the glands 



as far as the muscularis mucosae ; at this level they form a plexus from which vessels 

 descend into the areolar coat to join the wide-meshed submucous plexus. Larger 

 lymphatics pierce the muscular tunic and unite to form the chief channels which 

 escape from the walls of the stomach along both curvatures to empty into the lymph- 

 nodes which occur in these situations. 



The nerves supplying the stomach are from the pneumogastric and the 

 sympathetic, and contain both meduUated and nonmedullated fibres, the latter 



predominating. On 



Fig. 1381. 



Stomach turned inside out, showing ilis.section of oblique and 

 circular muscular coats. 



r~- 



Mucosa 



fcubmucosa 



reaching the organ, the 

 stems pierce the exter- 

 nal longitudinal muscu- 

 lar layer, between which 

 and the circular layer 

 they form xheplexjts of 

 Aiierbach. The points 

 of juncture in this net- 

 work are marked by mi- 

 croscopic sympathetic 

 ganglia, from which 

 non-medullated fibres 

 supply the involuntary 

 muscle. Leaving the 

 intramuscular plexus, 

 twigs pass obliquely 

 through the circular 

 muscular tunic, and on 

 gaining the submucous 

 coat form a second net- 

 work, the plexus of 

 Meissner. Numerous 

 non-medullated fibres 

 leave the latter to enter 

 the mucous coat, in 

 which some end in deli- 

 cate plexuses supply- 

 ing the gastric glands 

 ( Ky tmano w ) , as well as 

 in special endings in the muscuferis mucosae (Berkley). Large medullated fibres, the 

 dendrites of sensory neurones, are also present within the mucosa, where they form 

 a subepithelial plexus after losing their medullary substance. The ultimate termi- 



Muscularis 



Serosa - 





Al^^^^^'l^ 



, 1 ransverse section of injected stomach, X 50. 



