394 



THE DIGESTIVE SYSTEM 



THE PANCREAS 



The pancreas is a flat elongate body lying behind the stomach be- 

 tween the loop of the duodenum and the spleen. It arises as two anlages : 

 a smaller from the common bile duct (ventral pancreas), and a larger 

 from the duodenum (dorsal pancreas). These subsequently fuse to form 

 a single organ drained mainly by the duct of the ventral component, 

 which has meanwhile made an anastomosis with that of the dorsal com- 

 ponent,, the latter proximal to the anastomosis nevertheless commonly 



FIG. 365. EARLY STAGES IN THE DEVELOPMENT OF THE PANCREAS, ILLUSTRATING 

 CONDITIONS IN THE 5 AND 7 WEEKS OLD HUMAN EMBRYOS. 



Dp, dorsal pancreas; Vp, ventral pancreas; Pd, pancreatic (Wirsung's) duct; 

 Apd, accessory pancreatic (Santorini's) duct; Dch, ductus choledochus; cd, cystic 

 duct; Hd, hepatic duct. (Adapted from Kollman.) 



remaining pervious and functional. The pancreas bears a close struc- 

 tural resemblance to the salivary glands, more especially the parotid. 

 It is a compound tubulo-acinar gland which contains an immense num- 

 ber of small lobules associated into lobes and which pours its secretion 

 into the lumen of the duodenum by means of the chief (Wirsung's) 

 and accessory (Santorini's) pancreatic ducts. The lobules are united by 

 a delicate and relatively very loose fibro-elastic connective tissue. 



The ducts of the pancreas branch and arborize in the same manner as 

 those of the salivary glands. The interlobular ducts are lined by a 

 single layer of columnar cells; in the larger divisions (interlobar ducts) 

 occasional goblet cells are found. The wall of the interlobular pan- 

 creatic ducts is much thicker than in those of the salivary glands, for 



