i8o 



TEXT-BOOK OF PHYSIOLOGY. 



(Fig 74) Glands with these histologic features are most abundant 

 in the middle zone of the stomach. Toward the extreme left end 

 of the fundus the glands are largely, if not entirely, devoid of pari- 

 etal cells. 



The pyloric glands are also formed by an involution ot the 



mucous membrane and lined by epi- 

 thelial cells (Fig. 75). The ducts 

 are much longer than the ducts of 

 the fundic glands. At its extremity 

 each duct becomes branched, giving 

 rise to a number, from 2 to 16, of 

 short tubes, each of which has a large 

 lumen and communicates with the 

 duct by a narrow short neck. The 

 ducts are lined throughout by colum- 

 nar epithelium. According to Mall, 

 the total number of openings on the 

 surface of the mucous membrane of 

 the dog's stomach is somewhat over 

 1,000,000, and the total number of 

 blind tubes opposite the muscularis 

 mucosa exceeds 1 6, 500,000. ^Accord- 

 ing to Sappey, the surface of the 

 mucous membrane of the human 

 stomach presents over 5,000,000 ori- 

 fices of gastric glands^ 

 Blood-vessels, Nerves, and Lymphatics. The blood-vessels 

 of the stomach after entering the mucosa break up into a number of 

 branches which are distributed to the muscular and mucous coats. 

 The branches to the latter soon form a capillary network with oblong 

 meshes which not only surround the tubules but form a network just 

 beneath the surface of the mucosa. Veins gradually arise from the 

 capillaries which empty into the larger veins of the mucosa. The 

 glands are also supported by processes of smooth muscle-fibers 

 passing up from the muscularis mucosa. 



The nerve-fibers distributed to the stomach are derived from the 

 vagus and the sympathetic branches of the solar plexus. After 

 piercing the serous coat the fibers form or unite with a plexus of 

 fibers situated between the circular and longitudinal layers of the 

 muscle-coat. \At the nodal points of this plexus large nerve-gang- 

 lion cells are to be found, the whole forming the mechanism known 

 as Auerbach's plexus. A similar plexus of cells and fibers in more 

 or less intimate anatomic connection with the foregoing is found 

 between the muscle and submucous coats, and is known as Meiss- 

 ner's plexus.^From this plexus fine nerve filaments are distributed 



FIG. 75. SECTION OF PYLORIC 

 GLANDS FROM HUMAN STOM- 

 ACH, a. Mouth of gland 

 leading into long, wide duct 

 (6), into which open the ter- 

 minal divisions, c. Connec- 

 tive tissue of the mucosa. 

 (After Pier sol.} 



