GASTRIC GLANDS. 837 



faces ; and their inner surface is lined with cells. At the pyloric end of the 

 stomach these cells appear to be entirely lined with a simple layer of 

 columnar epithelium ; but in other portions of the organ, only the upper 

 fourth of the tubuli is occupied by epithelium of that character ; the lower 

 three-fourths containing finely granular nucleated cells, which are polygonal 

 or oval in form, are much larger than the columnar, and do not form a 

 stratum on the surface, but completely fill the cavity : these have been 

 termed peptic cells. It has been supposed that only those glands which 

 possess the last-mentioned form of epithelium secrete the gastric juice, and 

 they have accordingly been named peptic glands, and distinguished from the 

 mucous glands, in which the epithelium is columnar throughout. 



A marked distinction has been made out by various observers between peptic and 

 mucous glands of the stomach in the lower animals. Not only have their anatomical 

 characters been found to be different, but likewise their physiological properties, as 

 it has been ascertained that the gastric secretion only possesses its peculiar solvent 

 properties when proceeding from those parts of the stomach which contain glands of 

 the peptic kind. An abrupt separation, however, between the two varieties of gland 

 does not appear to exist in the human subject. (Henle, Syst. Anat. d. Mensch., vol. 

 ii., p. 158, where also other works are referred to.) 



Lenticular follicles, similar to those of Peyer's glands, are found in the 

 mucous membrane of the stomach, sometimes studding the greater part of 

 its surface, and giving occasionally a granular or mammillated appearance to 

 it. They are found in greater or less numbers all over the stomach, but are 

 most numerous towards the pylorus. They are best seen in the stomachs 

 of infants and children. Around the cardiac orifice they assume the charac- 

 ter of multilocular crypts. They are more frequently found open than shut, 

 the membrane which covers them being extremely delicate. (Allen 

 Thomson, in Goodsir's Annals, i. p. 36.) 



A distinct but delicate epithelium exists all over the stomach, covering 

 the margins and floors of the alveoli, and lining the tubuli also. It belongs 

 for the most part to the columnar variety, alternating in some parts with 

 the squaruous, which is composed of very minute polygonal scales. 



In animals, there is a more or less distinct layer of muscular fibres in intimate 

 relation with the simple basement-membrane. These fibres are of the plain or un- 

 striped variety, and are quite distinct from those which constitute the true muscular 

 coat, being separated from them by the submucous areolar layer. 



Vessels and nerves. The stomach is a highly vascular organ. Its arterial branches, 

 derived from all three divisions of the coeliac axis, reach the stomach between the 

 folds of the peritoneum, and form, by anastomosing together, two principal arterial 

 arches, which are placed along its two curvatures. After ramifying between the 

 several coats and supplying them with blood, and especially after dividing into very 

 small vessels in the submucous areolar tunic, the ultimate arterial branches enter the 

 mucous membrane, and ramifying freely, pass to its surface between the tubuli ; here 

 they form a plexus of very fine capillaries upon the wells of the tubules ; and from 

 this plexus larger vessels pass into a coarser capillary network upon the hexagonal 

 borders of the alveoli. The veins, corresponding with the arteries, arise from the 

 latter network (Brinton, "Stomach and Intestine " in Cyclop, of Anat.), and, after 

 forming a wide venous plexus in the submucous tissue, return the residual blood 

 into the splenic and superior mesenteric veins, and also directly into the vena portae. 

 By the breaking up of the arteries into capillaries on the walls of the glands, these 

 are furnished with pure blood for the elaboration of their secretion ; while it is the 

 blood from which that secretion has been drawn which passes on to the capillaries of 

 the free surface, and has added to it whatever materials may be taken into the cir- 

 culation from the contents of the stomach. 



