910 THE ORGANS OF DIGESTION. 



The gastric glands are of two kinds, which differ from each other in structure, 

 and it is believed also in the nature of their secretion. They are named respectively 

 pyloric and cardiac or oxyntic glands. They are both tubular in character, and 

 are formed of a delicate basement-membrane, lined by epithelium. The basement- 

 membrane consists of flattened transparent endothelial cells, with processes which 

 extend between and support the epithelium. The pyloric glands (Fig. 494) are 

 most numerous at the pyloric end of the stomach, and from this fact have received 

 their name. They consist of two or three short, closed tubes opening into a com- 

 mon duct, the external orifice of which is situated at the bottom of an alveolus. 

 The csecal tubes are wavy, and are of about equal length with the duct. The tubes 

 and duct are lined throughout with epithelium, the duct being lined by columnar 

 cells continuous with the epithelium lining the surface of the mucous membrane 

 of the stomach, the tubes with shorter and more cubical cells which are finely gran- 

 ular. The cardiac glands (Fig. 495) are found all over the surface of the stomach, 

 but occur most numerously at the cardiac end. Like the pyloric glands, they con- 

 sist of a duct, into which open two or more csecal tubes. The duct, however, in 

 these glands is shorter than in the other variety, sometimes not amounting to more 

 than one-sixth of the whole length of the gland ; it is lined throughout by columnar 

 epithelium. At the point where the terminal tubes open into the duct, and which 

 is termed the neck, the epithelium alters, and consists of short columnar or polyhe- 

 dral, granular cells, which almost fill the tube, so that the lumen becomes suddenly 

 constricted, and is continued down as a very fine channel. They are known as the 

 chief or the central cells of the glands. Between these cells and the basement- 

 membrane are found other darker granular-looking cells, studded throughout the 

 tube at intervals, and giving it a beaded or varicose appearance. These are known 

 as the parietal or oxyntic cells. Between the glands the mucous membrane con- 

 sists of a connective-tissue framework with lymphoid tissue. In places this latter 

 tissue, especially in early life, is collected into little masses, which to a certain 

 extent resemble the solitary glands of the intestine, and are by some termed the 

 lenticular glands of the stomach. They are not, however, so distinctly circum- 

 scribed as the solitary glands. Beneath the mucous membrane, and between it 

 and the submucous coat, is a thin stratum of involuntary muscular fibre (muscu- 

 laris mucosce), which in some parts consists only of a single longitudinal layer ; in 

 others, of two layers, an inner circular, and an outer longitudinal. 



Vessels and Nerves. The arteries supplying the stomach are the gastric, the 

 pyloric and right gastro-epiploic branches of the hepatic, the left gastro-epiploic 

 and vasa brevia from the splenic. They supply the muscular coat, ramify in the 

 submucous coat, and are finally distributed to the mucous membrane. The 

 arrangement of the vessels in the mucous membrane is somewhat peculiar. The 

 arteries break up at the base of the gastric tubules into a plexus of fine capillaries 

 which run upward between the tubules, anastomosing with each other, and ending 

 in a plexus of larger capillaries, which surround the mouths of the tubes and also 

 form hexagonal meshes around the alveoli. From these latter the veins arise, and 

 pursue a straight course downward betAveen the tubules, to the submucous tissue, 

 and terminate either in the splenic and superior mesenteric veins or directly in 

 the portal vein. The lymphatics are numerous ; they consist of a superficial and 

 deep set, which pass through the lymphatic glands found along the two curvatures 

 of the organ. The nerves are the terminal branches of the right and left pneumo- 

 gastric, the former being distributed upon the back, and the latter upon the front 

 part of the organ. A great number of branches from the sympathetic also supply 

 the organ. 



Surface Form. The stomach lies for the most part in the left hypochondriac region, but 

 also slightly m the epigastric region, and is partly in contact with the abdominal wall, partly 

 under cover of the lower ribs on the left side, and partly under the left lobe of the liver. Its 

 cardiac orince corresponds to the articulation of the seventh left costal cartilage with the ster- 

 num ' if if Py lo , rlc or . lfic , e 1S ln a vertical line drawn from the right border of the sternum, two 

 and a halt or three inches below the level of the sterno-xiphoid articulation. According to 

 tfraune, when the stomach is distended, the pylorus moves considerably to the right, as much 



