86 



THE PHYSIOLOGY OF DIGESTION AND ABSORPTION 



central lumen. They are thought to communicate with the 

 lumen by capillary ducts, which may even penetrate their 

 substance. They are supposed to secrete hydrochloric acid, 



FIG. 37. Vertical section of the gastric mucous membrane. 



g, g, pits on the surface; p, neck of a fundus-gland opening into a duct, g; x, pari- 

 etal, and y, chief cells; a, v, c, artery, vein, capillaries; d, d, lymphatics, emptying 

 into a large trunk, e. (Landois.) 



and are called acid cells from this fact, or parietal cells from 

 their position. (See Fig. 37.) 

 Method of Secretion. When food is ingested gastric move- 



