THE DIGESTION 



217 



pi. 



vessel and a very small lymphatic called a lacteal. Since 

 the villi are so thickly placed as to cover the entire mucous 

 coat of the intestine like the fibers in a piece of velvet, 

 the absorbing surface is enormously increased. 



The digestive fluids that enter the small intestine are the 

 pancreatic fluid from 

 the pancreas, the bile 

 from the liver, and 

 the intestinal juice 

 from the small in- 

 testinal glands (Figs. 

 172 and 174). 



387. The Pancreas 

 and its Secretions. 

 The pancreas, or 

 sweetbread, is flat, 

 narrow, and about six 

 inches long. It lies 

 behind the stomach, 

 and tapers toward 

 the left, ending above 

 the left kidney. Its 

 shape has been com- 

 pared to a dog's 

 tongue and like the FlG> I72> ~~ To show the Structure of the Wal1 olf 



the Small Intestine. 



root of the tongue, , . 



v, villi, and g, glands of the mucous membrane; 



it bends downward c.m., circular muscle layer; Im, longitudinal muscle 

 , layer: /, peritoneum, or serous coat. 



at its broader end, 



where its duct leaves it and joins the bile duct just before 

 emptying into the duodenum. Its internal structure re- 

 sembles the salivary gland, and it is called by the Germans 

 the abdominal salivary gland. The amount of digestion 

 accomplished in the small intestine is greater than in any 

 other division of the canal, and the pancreas is the most 

 active and powerful of all the glands. Its secretion, the 



