SUMMARY 191 



tures which make possible tissue respiration, by supplying oxygen 

 to the blood. The red corpuscles in the lungs lose the carbon 

 dioxide that they have taken from the tissues, replacing it with 

 oxygen. This is accompanied by a change from dull red (blood 

 which is poor in oxygen) to bright red (richlj^ oxygenated blood) . 

 Other changes take place in other parts of the body. In the walls of 

 the food tube, especially in the small intestine, the blood receives 

 its load of fluid food. In the muscles and other working tissues 

 the blood gives up food and oxygen, receiving carbon dioxide and 

 organic waste in return. In the liver, the blood gives up sugar, 

 and the worn-out red corpuscles which break down and are re- 

 moved from the circulation. In the glands, the blood gives up 

 the materials used by the gland cells in their manufacture of se- 

 cretions. In the kidneys, it loses water, urea, and other wastes. 

 In the skin, it also loses some waste materials, salts, and water. 



Problem Questions 



1. How are the lungs adapted to do their work? 



2. Explain the mechanics of breathing. 



3. What are the products of respiration ? 



4. Explain the principles underlying the Schaefer method of artificial 

 respiration. 



5. What is ventilation? Why is it necessary? 



6. What is cell respiration ? Explain fully. 



7. How does the kidney do its work? 



8. How does the skin excrete wastes? 



9. What is a congestion and how is it caused ? 

 10. How do we " take cold" ? 



Problem and Project References 



Hunter, Laboratory Problems in Civic Biology. American Book Company. 



Broadhurst, Home and Community Hygiene. J. B. Lippincott Company. 



Fisher and Fisk, How to Live. Funk & Wagnalls Company. 



Harrow, Glands in Health and Disease. E. P. Button and Company. 



Hough and Sedgwick, The Human Mechanism. Ginn and Company. 



McCarthy, Health and Efficiency. Henry Holt and Company. 



Martin, The Human Body, Advanced Course. Henry Holt and Company. 



Sharp, Foundation of Health. Lea and Febiger. 



Woodman and Norton. Air, Water and Food. John Wiley and Sons. 



