ORGANS OF DIGESTION. 115 



thoracic cavity it lies dorsal to the heart (Fig. 55) by the 

 side of the aorta. Immediately caudad of the diaphragm 

 it opens into the cardiac end of the stomach (Fig. 60). 



STOMACH. 



The stomach is that dilated portion of the canal lying 

 immediately caudad of the diaphragm on the left side. The 

 esophageal end of the stomach is known as the cardiac por- 

 tion, and the intestinal end is the pyloric portion (Fig. 60). 

 Here a circular fold of mucous membrane embraced by a 

 sphincter muscle serves as a valve to open and close the 

 pylorus or gateway to the intestine. The dorsal surface of 

 the stomach is its lesser curvature and the ventral convex 

 surface is its greater curvature. The structure of the walls 

 of the stomach is described below. 



INTESTINE. 



The intestine is that much contorted portion of the canal 

 leading from the stomach to the external aperture or anus. 

 The first portion, the small intestine (Fig. 60), is about 

 three feet long in a large cat, and is less in diameter and 

 much more convoluted than the second portion, or large 

 intestine. 



The small intestine consists of three parts: the duode- 

 num, the jejunum, and the ileum. The duodenum is the 

 first twelve or fifteen centimeters. A duct from the liver 

 and the gall-bladder and two ducts from the pancreas, 

 empty into it. The former is the common bile duct and 

 the latter are the pancreatic ducts. The jejunum is the 

 portion of the small intestine next to the duodenum. It 

 is about twenty-five centimeters long. No special mark 

 indicates its limits. It is so called because that portion 

 of the canal in man is frequently empty after death. The 



