1280 THE ORGANS OF DIGESTION 



wall, and both to the lesser omentum. The termination of the gastric anastomoses with the 

 pyloric branch or two rami of the pyloric branch of the hepatic artery. From each arch six or 

 seven descending branches come off to the anterior and posterior walls of the stomach. The 

 gastroduodenal artery is given off by the hepatic. From the gastroduodenal comes the right 

 gastroepiploie. The left gastroepiploic comes from the splenic. The right gastroepiploic 

 artery passes from right to left in the gastrocolic omentum below the greater curvature of the 

 stomach. The left gastroepiploic artery passes forward in the gastrosplenic omentum to 

 below the greater curvature of the stomach, and passes from left to right along that curvature 

 in the greater omentum, and joins the right gastroepiploic artery. The gastroepiploic arteries 

 are not upon but are distinctly below the stomach wall. From them numerous gastric branches 

 are sent to the anterior and posterior walls of the stomach, and they anastomose with branches 

 of the gastric and pyloric. Vasa brevia, four or five in number, arise from the splenic, pass 

 forward in the gastrosplenic omentum, and supply the fundus. The arteries of the stomach lie 

 first beneath the peritoneum, but soon enter the muscular coat, supply it, pierce it, ramify in the 

 submucous coat, and are finally distributed to the mucous membrane. The arrangement of the 

 vessels in the mucous membrane is somewhat peculiar (Fig. 1005). The arteries break up 

 at the base of the gastric tubules into a plexus of fine capillaries which run upward between 

 the tubules, anastomosing with each other, and ending in a plexus of larger capillaries, which 

 surround the mouths of the tubes and also form hexagonal meshes around the crypts. 



The capillary network about the glands gives origin to the veins. The various small veins 

 unite and form a plexus in the submucous tissue (Fig. 1005). From this plexus come branches 

 which pass through the muscular coat and terminate in the right gastroepiploic branch of the 

 superior mesenteric, the left gastroepiploic branch of the splenic, the veins to the splenic which 

 correspond to the vasa brevia arteries, and the gastric or coronary branch of the portal. 



The lymphatics (Figs. 570 and 571) arise in the mucous membrane and terminate in a net- 

 work in the submucous tissue. From this network trunks arise which perforate the muscular 

 coat in the regions of the curvatures and terminate in the seromuscular collecting trunks. The 

 details of the lymphatic drainage of the stomach are given on page 795. 



The nerves of the stomach come from the right and left vagi and from the solar plexus of 

 the sympathetic. The left vagus passes to the front of the stomach, and the right nerve passes 

 to the back, and they unite with the fibres of the sympathetic. The fibers thus formed are mostly 

 amyelinic. They form Auerbach's plexus in the muscular coat between the circular and longi- 

 tudinal fibres and Meissner's plexus in the submucous coat, the latter plexus being formed by 

 fibres from the former. Auerbach's plexus supplies the muscular coat of the stomach, while 

 fibres from Meissner's plexus ramify in the submucous coat and terminate in the muscularis 

 mucosae and the mucous membrane, branches passing to the gastric glands and to just beneath 

 the epithelium. (See nerve supply of small intestine, p. 1296.) 



Relations of the Stomach. The antero-superior surface is in relation with the left 

 and quadrate lobes of the liver, the ventral abdominal parietes, and the costal portion of the 

 Diaphragm. The postero-inferior surface is in relation with the lumbar portion of the Dia- 

 phragm, the pancreas, and the transverse mesocolon, while the fundus may come into contact 

 with the left kidney and suprarenal gland, the spleen, and splenic flexure of the colon. The lesser 

 curvature is directed toward the transverse fissure of the liver, while the greater curvature may 

 be in contact with the transverse colon. 



Movements and Innervation of the Stomach. 



Movements. It has apparently been demonstrated that the stomach "consists of two parts 

 physiologically distinct." 1 The cardiac portion of the stomach is a food reservoir in which 

 salivary digestion continues; the pyloric portion is the seat of active gastric digestion. Cannon 

 affirms that there are no peristaltic waves in the cardiac portion, but that as the food passes from 

 the pyloric portion into the intestines, tonic contraction of the muscles of the fundus squeezes the 

 contents of the pyloric portion. Moritz, Levan, and Cannon assert that muscular activity is 

 chiefly manifested in the pyloric portion. In this portion during digestion there is a succes- 

 sion of peristaltic waves, which waves in the human being pass at the rate of three per minute 

 (Moritz). Cannon points out that the efficiency of peristalsis in mixing the food depends 

 upon the contraction of the pyloric sphincter. So long as the sphincter holds, each constric- 

 tion ring coursing from the middle to the end of the stomach presses the food into a blind pouch ; 

 the food, unable to escape through the pyloric opening, has as its only outlet the opening in 

 the advancing ring. This is an admirable device for bringing the food under the influence of 

 the glandular secretions of the pyloric region. For, as a constriction occurs, the secreting sur- 

 face enclosed by the narrowed muscular ring is pressed close around the food within the rim'. 

 As the constriction advances it continually presses inward fresh glandular surfaces, and further- 



1 Walter B. Cannon, Medical News, May 20, ItOS. 



