12 THE FROG 



2. The Digestive Organs 



Push a needle handle or pipette into the opening of the 

 oesophagus (20), if possible as far as the stomach (35), 

 and raise the livery without cutting anything. Trace the 

 entire digestive system, noting that it is essentially a tube, 

 or canal with an anterior and posterior aperture, and having 

 two large glands, the liver and pancreas, emptying into it. 

 Locate the following structures which have not been pre- 

 viously noted: 



40. The cardiac end of the stomach is that into which 

 the oesophagus enters. 



41. The posterior or pyloric end is where the stomach 

 empties into the duodenum (37). 



42. The bile duct can be demonstrated in a fresh spec- 

 imen by squeezing the gall bladder (34) gently. 

 From the gall bladder it empties into the duodenum 

 a short distance below the pyloric end of the stom- 

 ach. It is formed by the union of the 



43. hepatic ducts, leading from the lobes of the liver 

 and 



44. is connected with the gall bladder by the cystic 

 ducts. 



45. The ducts of the pancreas (36) open into the bile 

 duct but are not easily demonstrated. 



46. The duodenum continues caudal to the point where 

 the bile duct enters as the small intestine or ileum. 



47. The ileum terminates in the large intestine or rectum, 

 which enters 



48. the cloaca, the external aperture of which is the 

 vent (12). 



