1736 



HUMAN ANATOMY. 



Connective- 

 tissue envelope 



Capillary 

 blood-vessel 



tion from the surrounding glandular tissue and their close relation with the blood- 

 vessels, the opinion is held by many that they produce some substance which passes 

 directly into the blood and may be regarded, at least provisionally, as concerned in 

 "internal secretion." 



The Pancreatic Ducts. — The gland is surrounded by a fibrous sheath which 

 sends in many processes dividing it into small lobules. The chief excretory canal in 

 the adult is the diid of Wirsiing (ductus pancreaticus), which, beginning near the end 

 of the tail, runs through the middle of the pancreas towards the right, and bends 

 downward as it passes through the head. Branches sprout from the main duct 

 at right angles, which receive bunches of smaller ramifications. The diameter of 

 the duct near its end is about 5 mm. It descends just in front of the common bile- 

 duct to the wall of the duodenum and empties in common with it at the papilla 

 (Fig. 1455). -^ts termination very often is in the floor of the ampulla (diverticulum 

 duodenale), so that the papilla presents but one opening. The tributary ducts of the 

 head are larger than the others. A particularly large one — the duct of Sayitorini 



( ductus pancreaticus acces- 

 Ftg. 1464, sorius) — is in the early 



stage of development the 

 chief duct of the head, 

 and consequently of the 

 gland. In the adult it 

 usually descends from the 

 right to empty into the 

 duct of Wirsung as the 

 latter turns downward. 

 In about half the cases, 

 according to Schirmer,^ it 

 opens independently into 

 the duodenum, some 3 

 cm. above the papilla and 

 more anteriorly. The or- 

 ifice is usually surrounded 

 by a small raised ring. 



Modified 

 epithelial cells t-- i ^ • ^• 



Even when so termmatnig 

 it retains its connection 

 with the duct of Wir- 

 sung. Thus fluid in the 

 body of the pancreas may 

 in such cases pass into 

 the duodenum bv either 

 opening, and fluid in the 

 duct of Santorini may pass either directly into the gut or through the duct of Wir- 

 sung. The canal of Santorini may be no more than an insignificant side branch of 

 the other, or it may be the chief, or sole, excretory duct. 



Relations to the Peritoneum. — Although developed in both the posterior 

 and the anterior mesenteries, the pancreas, owing to the changes by which the spleen 

 on the left and the descending part of the duodenum on the right have come to lie 

 against the posterior abdominal wall, is entirely retroperitoneal. The posterior sur- 

 face, with the possible exception of the end of the tail, which may be surrounded by 

 peritoneum, is attached to the parts behind it by connective tissue. The layers of 

 peritoneum covering the antero-superior and the inferior surfaces meet to form the 

 transverse mesocolon, which is attached along the border between these surfaces, and 

 is continued on the right across the head, and may sometimes rise towards the left 

 onto the antero-superior surface. The gastro-pancreatic fold, made by the gastric 

 artery, crosses the gland upward from a point a varying distance below the coeliac 

 axis. 



Vessels. — The arteries are many small branches derived from the splenic, 

 hepatic, and superior mesenteric. As the splenic runs along the top of the posterior 



^ Beitrage zur Geschichte and Anatomie des Pancreas, Basel, ;893. 



Alveolus with 

 ordinary cells 



Section of pancreas, showing island of Langerhans. X 200. 



