480 



MANUAL OF HISTOLOGY. 



The lymplioid follicles of the gastric mucous membrane have long been 

 known under the name of the lenticular glands. They are not always to 



be found in man, but are of rather 

 exceptional occurrence, varying greatly 

 in number, also, wherever they are 

 present. 



The vascular system of the stomachal 

 mucous membrane (tig. 466), upon 

 which the secretion of the gastric 

 juice and absorption of the fluid con- 

 tents of the stomach is dependent, is 

 very characteristic ( 197). The arte- 

 ries undergo division immediately on 

 arriving in the submucosa, so that 

 they arrive at the under surface of 

 the true mucous membrane in the 

 form of very fine twigs having an 

 oblique course (figs. 466 and 467, c). 

 Here, with but slightly diminished 

 calibre, they are finally resolved into 

 a delicate network of capillaries (fig. 

 467, d), whose tubes of 0-0070- 

 0-0038 mm. are woven around the pep- 

 tic glands forming elongated meshes 

 (figs. 466and 468). Thus they advance 

 as far as the surface of the mucosa, 

 where the orifices of the glands are sur- 

 rounded in a circular mesh-work, and 

 loops are prolonged into any papillae 

 that may be present (fig. 466, above). It is from this last portion of 

 the vascular apparatus alone that the transition of arterial into venous 

 blood takes place. The radicals of the veins are more or less scattered, 

 so that a certain amount of resistance is offered to the flow of blood into 



them. These venous twigs, then, 

 become very rapidly developed into 

 trunks of considerable calibre, which 

 traverse the mucous membrane per- 

 pendicularly downwards to empty 

 themselves eventually into a wide- 

 meshed network lying horizontally 

 underneath the latter (figs. 466 and 

 467, b, a). This arrangement per- 

 sists, as a rule, throughout the vari- 

 ous species of mammals, with slight 

 modifications, affecting principally 

 the surface of the mucous membrane. 

 In the long-meshed network of 

 capillaries we have before us that 

 . 467 -From the stomach of the dog. a a portion of the vascular system pre- 



vem ; 6, its branches ; r, an arterial twig break- L . . . , . i . . 



ing up into a capillary network (d) for the Siding OV6r the Secretion OI the organ, 



and in the round meshed network 



with the venous radicals, that part formerly erroneously supposed to be 

 devoted to absorption. 



Fig. 466. Vascular network of the human 

 gastric mucous membrane (half diagramma- 

 tic). A fine arterial twig breaks up into a 

 long-meslied capillary network, which passes 

 again into a round-meshed around the open- 

 ings of the glands. From this latter the vein 

 (the large dark vessel) takes its origin. 



