THE PANCREAS IOI 



Histology. This is a compound tubular gland. The cells 

 in the alveoli are of the serous type and are granular toward the 

 central lumen. During activity they undergo changes Very 

 similar to the salivary cells, the non-granular zone toward the 

 basement membrane increasing and extending and the granular 

 zone becoming correspondingly smaller. Here, as in the sali- 



4 



FIG. 42. One saccule of the pancreas of the rabbit in different states of 

 activity. (From Brubaker after Yeo.) 



A , after a period of rest, in which case the outlines of the cells are indistinct and the 

 inner zone *'. e., the part of the cells (a) next the lumen (c) is broad and filled with 

 fine granules. B, after the gland has poured out its secretion, when the cell outlines 

 (d) are clearer, the granular zone (a) is smaller, and the clear outer zone is wider. 



vary glands, it is believed that the granules are made from the 

 clear protoplasm, and contain the enzymes or their formative 

 materials. The formative material in all these glands is given 

 the name of zymogen, although the zymogen in a particular 

 gland may have a particular name, as pepsinogen, the forerunner 

 of pepsin, or trypsinogen, the forerunner of trypsin. 



Properties and Composition of Pancreatic Juice. The 

 pancreatic juice is a colorless liquid, alkaline in reaction, and has 

 a specific gravity of about 1040 if taken from a recent fistula. It 

 coagulates when heated and is prone to putrefaction on exposure. 

 With a specific gravity of about 1040, it contains per thousand 

 about 900 parts water, the remainder being different solid food 

 materials in solution. These constituents are a proteid and 



