PROBLEM QUESTIONS 249 



General Conclusion. Explain the functions of the skin in the 

 light of the above experiments. 



The skin as an organ of sensation will be treated later. 



Fill out the foregoing summary of changes taking place in blood 

 within the organs of the body. 



PROBLEM QUESTIONS 



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



2. How is oxygen of use to the body? 



3. Show two means by which oxygen is taken into the lungs. 



4. Why should we practice deep breathing exercises each 

 day? 



5. What habits of bad posture harm the lungs ? Explain your 

 answer. 



6. What changes take place in the blood within the lungs? 



7. What changes take place in air within the lungs? 



8. What is given off in the air from the lungs as a result of oxi- 

 dation ? 



9. What is oxidation ? Where does it take place in the human 

 body? 



10. Show exactly how oxygen reaches the cells of the body. 



1 1 . What does a cell do as a result of oxidizing food ? 



12. Why should people sleep with windows open? 



13. Make a diagram to show how to ventilate a room. 



14. How would you ventilate through a window without making 

 a draft? 



15. Can you explain the school system of ventilation? Is it a 

 good one? (Remember that hot air rises and takes up with it 

 carbon dioxide.) 



16. Explain the advantage of using damp sawdust when sweep- 

 ing. 



17. How would you prevent dust in a sleeping room? In a 

 schoolroom ? 



18. Which is cleaner, a paved or an unpaved street? Why? 



19. Why is street sprinkling a good thing? 



20. Which is most cleanly: a lamp, gas, or electricity? Why? 



