CHAPTER XXXII. 



THE CONTROL OP THE PANCREATIC SECRETION. 

 THE SECRETION OF BILE. 



As an example of THE CONTROL OF GLANDULAR FUNCTION 

 THROUGH HORMONES it is most convenient to take the pancreas. 

 The hormone for this gland is derived from the duodenal mucosa 

 where it is produced by the action of the acids present in the chyme 

 on a constituent of the epithelial cells, and it is then carried to the 

 pancreas by the blood. 



Demonstration 9. An anaesthetized dog that has been starv- 

 ed for 24 hours is prepared for registration of the arterial blood 

 pressure, and a cannula is inserted in the femoral vein. The abdo- 

 men is opened in the linea alba and the duodenum along with the 

 adherent pancreas pulled out of the wound. The lower (and 

 larger) duct of the pancreas is then exposed, and a ligature placed 

 under it. The position of this duct is indicated approximately by a 

 small lobe of pancreas, accompanied by bloodvessels, which extends 

 to the duodenum at a distance of about 20-25 mm. above the 

 point where the head of the pancreas leaves the duodenum. It 

 must be remembered that the duct begins branching very close to 

 its insertion into the duodenum so that only a small piece of it can 

 be dissected free. To insert a cannula into the duct the duodenum 

 is opened by a longitudinal incision along its free border opposite 

 the duct, the opening of which is then visible in the centre of a small 

 papilla of somewhat paler tissue than the remainder of the mucosa. 

 A blunt probe should be inserted into the duct and gently guided 

 along it so as to ascertain the exact direction of the duct and the 

 position of the first branch. As the probe is withdrawn a suitable 

 cannula with a well-marked neck is inserted and tied in position 

 by the ligature previously applied outside the duct. A cannula is 

 now placed in the common bile duct, which is readily found accom- 

 panying the portal vein. 



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