The Digestive System - 317 



12. 



13. 



14. 



16. 



17. 



18. 



19. 



20. 



Make a labeled diagram showing the con- 

 nections of the human pharynx; discuss these 

 connections in relation to the swallowing re- 

 flexes. 



Explain how the mechanisms controlling the 

 flow of saliva and pancreatic juice are dif- 

 ferent. 



Name three hormones that are important in 

 controlling the flow of the digestive juices, 

 and in each case specify: 



a. the site of production of the hormone 



b. the gland (or other part) which is spe- 

 cifically activated by the hormone 



c. the manner in which the hormone 

 reaches the effector organ 



Plan an experiment that would prove that 



the pancreas is activated by a substance (or 



substances) that is carried in the blood 



stream. 



Discuss the innervation of the stomach in 



relation to the gastric movements. 



What is a sphincter valve? Specify four 



sphincters present in the gastrointestinal 



tract of man; explain the different functions 



of these valves. 



Describe the movements of the stomach in 



relation to: 



a. the churning of the chyme 



b. the evacuation of the chyme from the 

 stomach 



Explain how the early work of Spallanzani 

 and Beaumont contributed to an understand- 

 ing of the composition and functions of the 

 gastric juice. 



How did Pavlov prove that seeing, smelling, 

 and tasting food elicit a flow of gastric juice 

 even when the food doesn't reach the stom- 

 ach? How is this part of the secretion effected? 

 What is rennin? What important role is 



played by rennin in the digestive processes of 

 man and other mammals? 



22. Make a labeled diagram to show the essen- 

 tial relations of the duodenum to the stom- 

 ach, pancreas, and liver. 



23. The gastric chyme is highly acid, whereas the 

 intestinal chyme is definitely alkaline. Ex- 

 plain precisely where and how this transition 

 is effected, and why it is important. 



24. Explain the relation between: 



a. the blood pigments, bile pigments, and 

 fecal pigments 



b. the bile pigments and jaundice 



c. the "concentrating function" of the 

 gall bladder and gallstones 



d. gallstones and the bile salts 



25. Describe and explain the circulation of bile 

 salts. 



26. Describe the movements of the small intes- 

 tine and explain their significance. 



27. Differentiate between: (a) trypsin and chy- 

 motrypsin; (b) trypsin and trypsinogen; (c) 

 casein and caseinogen; (d) endopeptidases 

 and exopeptidases. 



28. For each of the enzyme groups mentioned 

 in Question 27, give an example and specify 

 the catalyzed reaction. 



29. Compare the movements of the small and 

 large intestines. 



30. Make a carefully labeled diagram showing 

 the relations of the colon to the ileum, cae- 

 cum, appendix, rectum, and anus. 



31. Briefly discuss: (a) the functions of the colon; 

 (b) the importance of the colonic bacteria. 



32. What is the gastrocolic reflex and how is it 

 related: (a) to defecation: (b) to the symp- 

 toms of "autointoxication"? 



33. Specify three different kinds of cathartics 

 and explain the mode of action of each. 



The Living Body, 4th ed., by C. H. Best and 

 N. B. Taylor; New York, 1958. 

 The Body functions, by R. W. Gerard; New 

 York, 1941. 



FURTHER READINGS 



3. The Machinery of the Body, by A. J. Carlson 



and V. Johnson; Chicago, 1953. 



