102 



ANATOMY AND PHYSIOLOGY OP 



end, as in the former it is but a mere con- 

 tinuation of the unmodified mucus lining 

 of the oesophagus, being characteristic for 

 its scantiness in gland and but limited sup- 

 ply of blood. The most marked feature it 

 possesses is that of being covered by a cuti- 

 cular layer of extreme thickness, easily 

 separable from the basement structure be- 

 neath after slight maceration or boiling. 

 The cardiac portion of the gastric mucus 

 lining is, in a healthy stomach, of a dirty 

 white, bedewed by more or less mucus, 

 and thrown into folds which have a radiated 

 arrangement at the cardiac orifice, whilst at 

 the fundus they are concentrically arranged. 

 This portion of the membrane is also fur- 

 nished with papillae ; and Sprott Boyd, in 

 an Inaugural Essay on the structure of the 

 Mucus Membrane of the Stomach, pub- 

 lished in the Edinburgh Medical and Surgi- 

 cal Journal for 1836, describes a very marked 

 peculiarity of an interposed layer between 

 the epithelium and papiilated surface of the 

 mucus lining. This intermediate layer, he 

 says, has a smooth equal surface, perforated 

 by numerous foramina about the 600th of 

 an inch in diameter, or perhaps a little 

 smaller, the margins of which are slightly 

 thickened. He afterwards states that he 

 has not been able to trace in the epithelium 

 of any other animal a structure similar to 

 that existing in the horse. These peculiar- 

 ities in the left pouch of the stomach cease 

 abruptly midway the length of the viscus, 

 where the cuticular lining terminates by a 

 serrated edge. 



The mucus lining of the right end of 

 the stomach is normally of a reddish color, 

 and presents a villous, glistening aspect, 

 coated thicldy with mucus, and also pos- 

 sessing a high degree of vascularity ; the 

 epithelium is here scanty, but nevertheless 

 tabular. The villous appearance above 

 referred to suggests itself also when the sur- 

 face is examined by the naked eye and by 

 the aid of a lens ; but it is deceptive, as 

 has been already remarked by Sprott Boyd, 

 who correctly refers it to the raised margins 

 of the arolaB which stud the surface. This 

 portion of the gastric mucus membrane is 



also thrown into folds, which become grad- 

 ually more marked towards the pylorus; 

 whereas they arc susceptible of obliteration 

 by distention, there is one circular fold at 

 the pylorus which is permanent, and so dis- 

 posed as to fulfil the office of a valve. 



The arteries of the stomach are derived 

 from the coeliac axis, whose three divisions, 

 i. e. gastric, hepatic, and splenic, all contri- 

 bute to supply blood to the viscus ; but the 

 first is specially destined to that office. The 

 gastric artery, being the smallest of the 

 three divisions, takes a course downwards, 

 forwards, and rather to the right, across the 

 pancreas, getting between the layers of the 

 gastro-hepatic omentum. Being then di- 

 rected to the left towards the lesser curva- 

 ture, it divides into an anterior left or smaller 

 branch, and a posterior right and more 

 capacious as well as longer one. The an- 

 terior division is destined to supply the 

 anterior surface of the stomach, and more 

 especially the left cul-de-sac, anastomos- 

 ing with branches (sometimes called vasa 

 breva), coming on to the stomach from the 

 splenic. This division of the gastic also 

 anastomoses with oesophageal twigs, which 

 are occasionally of considerable size. The 

 posterior or right division of the gastric 

 artery, destined for the pyloric end of the 

 stomach, anastomoses with some splenic 

 branches, but more especially with the py- 

 loric branches of the hepatic artery. 



The veins returning the blood from the 

 stomach are the gastric and splenic, which 

 anastomose with the duodenal veins. These 

 aU have a few valves, but they may be easily 

 injected from the porta into which they 

 empty, owing to their very free anastomosis. 



The lymphatics of the stomach are nu- 

 merous, and in some parts very apparent, 

 entering the lymphatic glands situated along 

 the greater curvature and around the cardia, 

 where they are numerous and large. 



The stomach is supplied with nerves 

 from both the cerebro spinal and sympathetic 

 or ganlionic system. The pneumogastric 

 or par vagna nerves, arising from the me- 

 dulla oblongata, are the main conductors 

 of nervous influence to and from that vis- 



