GLANDS CONNECTED WITH THE INTESTINAL CANAL. 301 



the dorsal surface of the organ so exposed. In the second method 

 the hver is drawn backwards, the various peritoneal folds which 

 connect the duodenum with the posterior border of the liver cut 

 through, and the three organs then separated ; the pancreas can 

 then be conveniently examined. 



The size and shape of the pancreas are subject to great variations 

 in different specimens. The usual shape of the organ is somewhat 

 triangular (Fig. 199), the left border being usually unbroken, while 

 the other two shorter borders are broken into lobes. The longest 

 lobe stretches as far as the pylorus {Pi/), to which it is attached by 

 connective-tissue : the opposite extremity of the gland is attached to 

 the liver. 



The excretory duct of the pancreas {Ductus Wirsiirgianus) opens 

 into the common bile-duct at about the middle of the pancreas 

 [F^) ; other smaller ducts may open into the same canal. 



b. Minute structure. [The pancreas consists of a number of 

 lobes loosely held together by connective-tissue ; each lobe is com- 

 posed of a number of lobules attached to each other much more 

 intimately. The lobules are made up of tubes lined by a single 

 layer of g-landular epithelium. This epithelium is, as a rule, broadly 

 columnar, but in the smaller tubes may be cubical or polygonal. 

 Each cell has a cell-wall, nucleus, and very granular protoplasm ; 

 the latter shows two zones (in the inactive condition), a granular 

 zone near the lumen, and an outer, clear, and finely striated zone 

 (Nussbaum). .The lumen of each alveolus is very small, and in 

 many cases difficult to make out. 



The smallest ducts have no special lining, and are therefore 

 bounded by the glandular cells; the larger ducts have a 

 flattened, cubical epithelium, which when seen from the sur- 

 face has an appearance as if the individual cells were w^idely 

 separated from one another ; these ducts have a considerable 

 layer of connective-tissue around them. The largest ducts are 

 lined with a layer of columnar, ciliated epithelium ; the cilia 

 are very long, usually of about the same length as the cell, some- 

 times appearing to be even longer. This epithelium is contin- 

 uous with the ciliated, epithelial layer of the common bile-duct, 

 which it resembles. These largest ducts have an extremely thick 

 layer of connective-tissue around them. 



The pancreas and its ducts are very richly supplied with vessels 

 and nerves ; the nerves forming everywhere a fine plexus, the larger 

 strands of which usiially, but not always, course with the larger 



