SPLANCHNOLOGY 155 



from this gall-bladder there is a duct, the cystic duct, which empties 

 into the small intestine toward the extremity of the second branch of 

 the duodenal loop. Another duct called the hepatic duct, proceeds 

 directly from the two lobes of the liver and empties into the intestine 

 just in front of the cystic duct. 



The Pancreas (Fig. 31, No. 17). Location and Shape. The pan- 

 creas, an organ lying in the duodenal loop is a yellowish-white, lobu- 

 lated gland, elongated in shape. Its average length in fowls of 

 average size is 4.96 inches, and the average weight about 0.008 pound. 

 The pancreas is divided into lobes, which in turn are divided into 

 lobules. 



Structure. The pancreas has a supporting connective tissue. 

 The lobules are made up of small alveolar glands, which are lined 

 with columnar epithelial cells. The ducts leading from the alveoli 

 are small; these unite to form larger ducts in which the epithelium 

 is taller. Between the alveoli throughout the pancreas there are 

 clusters of polyhedral cells which form the islands of Langerhans. 

 These islands are said to produce an internal secretion, or hormone, 

 which is absorbed by the blood or lymph capillaries and thus enters 

 the circulation (Fig. 38, B). 



Function. The function of the pancreas is to secrete a fluid con- 

 taining digestive ferments. 



The Spleen (Fig. 31, No. 21). Location. The spleen, or lien, 

 lies in a triangle formed by the proventriculus, the liver, and the 

 gizzard. 



Shape. It is a reddish-brown body shaped like a buckeye, is small 

 in size, weighing only about 0.005 pound. 



Structure. The outer surface of the spleen is covered by a reflec- 

 tion of the peritoneum. After this covering is removed, there is 

 observed a firm, white, fibrous layer, the cortical portion. This 

 covering sends into the interior small and large trabeculae, forming 

 a framework and dividing it into acini, or compartments. The 

 spaces are filled with a dark red parenchymatous material called 

 splenic pulp. The framework, in both deep and surface portions, 

 are found elastic fibers and smooth muscular fibers. 



The spleen is essentially a lymphatic organ, its peculiar structure 

 depending largely upon the arrangement of the blood-vessels. 

 Compact lymphatic tissue occurs in the spleen in spherical, oval, or 

 cylindrical collections of closely packed lymphoid cells. These 

 masses are known as the Malpighian bodies, or splenic corpuscles. 



