338 - Multicellular Animals, Especially Man 



d. other metabolic wastes pass from the 

 tells into the blood 



13. Why is the formation of lymph described as 

 a force filtration? 



14. Why is this process also called a colloidal 

 filtration? 



15. Compare the compositions of the plasma and 

 lymph in regard to: (a) protein content; (b) 

 content of glucose and amino acids: (c) con- 23. 

 tent of urea and inorganic salts: (d) relative 

 tonicity. 



16. Carefully explain the balance of forces that 

 accounts for: 



a. the escape of lymph from the plasma 



b. the backflow of some lymph into the 24. 

 plasma 



c. the flow of lymph from the tissue spaces 

 into the lymphatics 



17. Trace the general course followed by the 

 lymphatics which drain the tissue spaces of 

 each of the following regions: (a) wall of the 25. 

 small intestine: (b) left side of trunk and 

 head: (c) left leg: (d) right leg: (e) right side 



of the thorax and head. 



18. Is there any relation between the position of 26. 

 a "swollen gland" (lymph node) and the site 



of a particular infection? Explain. 



19. Explain the relation between muscular ac- 

 tivity and the flowing of the lymph. Of what 27. 

 importance arc the lymphatic valves? 



20. Differentiate between a single and a double 

 type of circulation: and between a two- 

 chambered and a four-chambered heart. 



21. On what grounds is the circulation of man 28. 

 and other mammals regarded as "more effi- 

 cient" than the circulation of the primitive 29. 

 vertebrates (fish)? 



22. In man and other mammals, all the blood 30. 

 that returns from the systemic circuit via 



the postcaval or precaval veins must pass 31. 

 through the pulmonary circuit before reach- 



ing the aorta and starting anew on the sys- 

 temic circuit (Fig. 17-10). Demonstrate the 

 truth of this statement by listing in proper 

 sequence the heart chambers, arteries, and 

 veins through which a certain sample of the 

 blood would have to pass in flowing from the 

 postcaval, or one of the precaval veins, to 

 the aorta. 



List in proper sequence the main branches 

 of the aorta (trunk line of the systemic cir- 

 cuit) and specify the parts or organs supplied 

 by each main branch. What three main veins 

 return the systemic blood to the right auri- 

 cle? 



As to the composition (aerated vs. unaerated) 

 of the blood conveyed: 



(a) how does the pulmonary artery differ 

 from all other arteries: 



(b) how does the pulmonary vein differ from 

 other veins? 



Make a labeled diagram to show how the 

 aorta, the carotids, the subclavian, and the 

 pulmonary arteries were evolved from the 

 gill arches of primitive vertebrates. 

 Make a labeled diagram showing the rela- 

 tions of the hepatic portal vein to the gastro- 

 intestinal tract, the liver, and the postcaval 

 vein. 



On the basis of the foregoing diagram, ex- 

 plain why it is impossible for substances ab- 

 sorbed from the gastrointestinal tract to reach 

 the general circulation without first coming 

 under the influence of the liver tissues. 

 Summarize what is known about the spleen 

 and its functions. 



Discuss the nature and significance of the Rh 

 factor. 



Explain the nature and significance of the 

 blood groups in man. 



Discuss the functions of the thymus gland. 

 Give experimental evidence. 



FURTHER READINGS 



The Living Body, by C. H. Best and N. B. 

 Taylor; New York, 1958. 



The Machinery of the Body, by A. J. Carl- 

 son and V. Johnson: Chicago, 1953. 

 Textbook of Anatomy and Physiology, by 



Kimber, Gray, and Stackpole; New York, 



1955. 



Blood Groups and Transfusions, by A. S. 



Weiner; Springfield (111.), 1943. 



Biology, by C. A. Villee; Philadelphia, 1962. 



