THE ABDOMEN 



8ll 



sunounded by large convoluted capillary vessels. These groups 

 constitute the islets of Langerhans, which are characteristic of the 

 pancreas. 



Excretory Apparatus of the Pancreas.— There is one principal 

 duct, called the pancreatic duct or duct of Wirsung. It is buried 

 in the substance of the gland, and is readily recognised by its 

 white colour. It lies nearer the posterior than the anterior surface, 

 and rather nearer the lower than the upper part of the gland. It 

 commences in the tail, whence it runs through the body as far 

 as the neck, receiving in its course a great many tributaries. On 

 arriving at the neck it gets a branch from the accessory pancreatic 

 duct, and then it describes a bend, and passes into the head in 

 a direction dowTiwards, backwards, and to the right. Finally, on 

 leaving the pancreas it meets with the common bile-duct, and the 

 two, entering the wall of the second part of the duodenum, terminate 

 in the manner already described (see p. 710). 



The accessory pancreatic duct or duct of Santorini is com- 

 paratively small, and varies much in size. If well developed, it 

 commences in the lower part of the head, where it takes up the 

 ducts of the lobules of that part. It then passes upwards with an 

 inclination to the right, and divides into two branches. One of 



Pancreatic Duct 

 (Duct of Wirsung) 



Accessory Duct (Duct of Santorini) 



Ductus Communis 

 Choledochus 



Uncinate Process Dnct of \\'ursung 



Fig. 349. — The Pancreas and its Ducts (Posterior View). 



these joins the duct of Wirsung in the neck, whilst the other opens 

 into the second part of the duodenum at a point about i inch 

 above the common opening of the common bile-duct and duct of 

 Wirsung. The secretion conveyed by the duct of Santorini in early 

 life is usually regarded as flowing into the duodenmn, whilst in the 

 adult it is diverted into the duct of Wirsung. 



The tributaries of the principal duct, as well as of the accessory 

 duct, when followed into the pancreas, become in succession inter- 

 lobular and intralobular ducts. The intralobular ducts pass wathin 

 the lobules, and end in intermediary, jundiofial, or intercalary* ducts, 

 with which the alveoli or acini are directly connected. The part 

 of the duct between the intermediary and the intralobular duct 

 is called the neck. The walls of the intermediary ducts are thin, 

 and are formed of a basement membrane covered by flattened 

 * Interposed or inserted between the alveoli and the intralobular ducts. 



