264 DIGESTIVE SYSTEM. 



Situation and Connexion — explained at page 247. 



It possesses no peritoneal covering — that membrane simply 

 passes over its inferior surface. 



Division. — The pancreas has been divided into Iiead, bodi/, 

 and tail ; it has also a fourth part, attached to the right side of 

 the spine, a prolongation from its head, to which the name of 

 pancreas minoi- has been given. 



Structure. — Anatomists all agree, that there exists a similarity 

 of structure between this organ and the salivary glands; and 

 what tends to confirm this opinion, is, the resemblance that the 

 pancreatic fluid bears to common saliva. The pancreas is of a 

 pale red speckled colour, and is composed of manv small lobes 

 or rather lobules, which, though they intimately adhere together 

 by a fine cellular tissue, are perfectly distinct from one another in 

 regard to their ultimate organization. For every one of these 

 lobules, or (as some call them) acini, appears to be constituted 

 of a set of arteries, veins, and ducts, which vessels have no com- 

 munication, except through the medium of their trunks, with 

 those of any other ; so that a certain quantity of secretion is 

 prepared within, and discharged from, every one of them singly : 

 in fact, every lobule may be said to be a distinct gland of itself, 

 and this is precisely the case in respect to the salivary glands. 

 In the dissection of an injected pancreas, we may trace many 

 arterial twigs into these acini, which are detached at right angles 

 from the principal pancreatic artery as it pervades the interior of 

 the gland. The veins also may be seen accompanying the ar- 

 teries. The duct, which is the result of two main branches, has 

 a similar mode of ramification. Formed at the extreme end of 

 the gland, by the union of several smaller tubes, it takes its 

 course through the middle of the viscus, receiving in its way other 

 little ductiform vessels which come from the neighbouring lobules, 

 and contribute to augment its size. Thus formed, the long 

 branch issues from the body of the gland, the short and larger 

 one from the head and pancreas minor : the tw^o then form a 

 single trunk, about an inch in length, which extends directly 

 from the spleen to the duodenum, and pierces the latter alongside 

 of the hepatic duct. The tube is composed of a thin, pellucid 

 membrane of considerable strength, and is large enough in its 

 caliber to admit of the introduction of the finger. 



Organization. — The pancreatic arteries are derived mostly from 

 the hepatic : several, however, come from the splenic, in its course 

 to the left side of the abdomen ; and one or two from the gastric. 

 The veins are tributary to the vena portse. The small nerves dis- 

 covered in it are furnished by the coeliac plexus. 



