248 HANDBOOK OF PHYSIOLOGY-. 



and longitudinal) of unstriped muscular fibres, called the muscularis 

 mucoscB, which separate the mucous membrane from the scanty submu- 

 eous tissue. 



When examined with a lens, the internal or free surface of the stomach 

 presents a peculiar honeycomb appearance, produced by shallow polyg- 

 onal depressions, the diameter of which varies generally from yfoth to 

 3-l^th of an inch; but nearer the pylorus is as much as -j^th of an inch. 

 They are separated by slightly elevated ridges, which sometimes, espe- 

 cially in certain morbid states of the stomach, bear minute, narrow vas- 

 cular processes, which look like villi, and have given rise to the errone- 

 ous supposition that the stomach has absorbing villi, like those of the 

 small intestines. In the bottom of these little pits, and to some extent 

 between them, minute openings are visible, which are the orifices of the 

 ducts of perpendicularly arranged tubular glands (Fig. 185), imbedded 

 side by side in sets or bundles, on the surface of the mucous membrane, 

 and composing nearly the whole structure. 



Gastric Glands. Of these there are two varieties, (a) Peptic, (b) 

 Pyloric or Mucous. 



(a) Peptic glands are found throughout the whole of the stomach 



except at the pylorus. They are arranged 

 in groups of four or five, which are sepa- 

 rated by a fine connective tissue. Two or 

 three tubes often open into one duct, 

 which forms about a third of the whole 

 length of the tube and opens on the sur- 

 face. The ducts are lined with columnar 

 D epithelium. Of the gland tube proper, 



FIG. 186. -Transverse section *'<>'> the P art f the g land bel W the duct, 



the ^Per third is the neck and the rest 

 the tody- The neck is narr wer than the 

 body, and is lined with granular cubical 

 cells which are continuous with the columnar cells of the duct. Between 

 these cells and the membrana propria of the tubes, are large oval or 

 spherical cells, opaque or granular in appearance, with clear oval nuclei, 

 bulging out the membraua propria; these cells are called peptic or parie- 

 tal cells. They do not form a continuous layer. The body, which is 

 broader than the neck and terminates in a blind extremity or fundus 

 near the muscularis mucosae, is lined by cells continuous with the cu- 

 bical or central cells of the neck, but longer, more columnar and more 

 transparent. In this part are a few parietal cells of the same kind as in 

 the neck (Fig. 185). 



As the pylorus is approached the gland ducts become longer, and 

 the tube proper becomes shorter, and occasionally branched at the fun- 

 dus. 



