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PHYSIOLOGY. 



PANCREAS. 



The pancreas is a long gland, of a reddish-cream color, and is 

 situated behind the stomach. Its pointlike extremity comes in con- 

 tact with the spleen. It closely adheres to the duodenum. It is 

 about seven inches in length, its width about one and one-half 

 inches, and its thickness about one-half inch. The right and large 

 end is the head; its left free end is its tail. The duct of Wirsung, 

 or the pancreatic duct, the size of a goose-quill, runs the entire 

 length of the gland. Upon leaving the pancreas the duct penetrates 

 the wall of the duodenum, opening in conjunction with the common 

 biliary duct, about three inches from the pylorus. 



Fig. 25. Schematic Section of Pancreas. (VIALLETON.) 



1, Origin of excretory canal. 2, Centro-acinar cell. 3, Pancreatic cell. 

 4, Granular internal zone, zymogen granules. 5, External zone, clear part of 

 cell. 6, Nucleus. 7, Accessory nucleus. 



Structure. 



In structure the pancreas is an acino-tubular gland, resembling 

 the salivary glands. In fact, it has very frequently been called the 

 abdominal salivary gland. The lobes are composed of ducts which 

 have been convoluted, terminating in alveoli or sacs and which unite 

 with other tubules so as to communicate with the main duct. The 

 small ducts are lined with short columnar epithelial cells which are 

 smaller than those of the salivary glands. The secretory cells of 

 the pancreas are large and rounded, being distinctive in that they 

 possess an outer portion which is nearly or quite homogeneous, stain- 

 ing readily with dyes, and an inner portion, very granular, which 

 does not stain easily. The latter forms about two-thirds of the cell. 

 When the gland is inactive the cells are heavily charged with 



