244 HAND-BOOK OF PHYSIOLOGY. 



convoluted and more deeply situated. They are directly continuous with 

 Brunner's glands in the duodenum. (Watney.) 



Changes in the gland cells during secretion. The chief or cubical cells 

 of the peptic glands, and the corresponding cells of the pyloric glands 

 during the early stage of digestion, if hardened in alcohol, appear swollen 

 and granular, and stain readily. At a later stage the cells become 

 smaller, but more granular and stain even more readily. The parietal 

 cells swell up, but are otherwise not altered during digestion. The gran- 

 ules, however, in the alcohol-hardened specimen, are believed not to exist 

 in the living cells, but to have been precipitated by the hardening re- 

 agent; for if examined during life they appear to be confined to the inner 

 zone of the cells, and the outer zone is free from granules, whereas during 

 rest the cell is granular throughout. These granules are thought to be 



FIG. 180. Plan of the blood-vessels of the stomach, as they would be seen in a vertical section, 

 a, arteries, passing up from the vessels of submucous coat; 6, capillaries branching between and 

 around the tubes; c, superficial plexus of capillaries occupying the ridges of the mucous membrane; 

 d, vein formed by the union of veins which, having collected the blood of the superficial capillary 

 plexus, are seen passing down between the tubes. (Brinton.) 



pepsin, or the substance from which pepsin is formed, pepsinogen, which 

 is during rest stored chiefly in the inner zone of the cells and discharged 

 into the lumen of the tube during secretion. (Langley.) 



Lymphatics. Lymphatic vessels surround the gland tubes to a greater 

 or less extent. Toward the fundus of the peptic glands are found masses 

 of lymphoid tissue, which may appear as distinct follicles, somewhat like 

 the solitary glands of the small intestine. 



Blood-vessels. The blood-vessels of the stomach, which first break up 

 in the submucous tissue, send branches upward between the closely 

 packed glandular tubes, anastomosing around them by means of a fine 

 capillary network, with oblong meshes. Continuous with this deeper 

 plexus, or prolonged upward from it, so to speak, is a more superficial 

 network of larger capillaries, which branch densely around the orifices 



