PROBLEM 3. Hoiv Materials Are Moved to and fro?n Cells 223 



8. Explain clotting of blood, using the terms platelet, fibrin, and serum. 



9. Why must blood be tested before it is usrd for transfusion? What 

 are the four types? 



10. What are two advantages in using plasma instead of whole blood? 

 What can be used instead of plasma? 



11. What is the relative position and the structure of auricles and ven- 

 tricles in man? How does human heart muscle differ from other 

 muscle? 



12. When and by whom was the circulation of the blood first correctly 

 explained? How were his conclusions arrived at? 



13. How do arteries help to keep the blood moving? Why can the pulse 

 be felt only in certain parts of the human body? What causes the 

 pulse? 



14. What three kinds of tissues are found in the wall of an artery? Of 

 what importance is each? 



15. What may make the blood pressure rise above normal? What is a 

 cerebral hemorrhage? 



16. What should a person do who feels faint? Explain. Explain the pilot's 

 blackout. 



17. How do veins differ from and resemble arteries in structure? What 

 keeps the blood flowing through veins? Explain how the valves help. 



18. Through how many sets of capillaries does the human blood go in 

 one complete circulation? In which organs are these capillaries? Ex- 

 plain. Which veins carry bright red blood? Which arteries carry 

 maroon colored blood? Explain. 



19. What is accomplished by the valves in the human heart? 



20. What is lymph? Of what is it composed? Of what importance is it? 



21. What is accomplished by the lymphatics? What keeps lymph flowing^ 

 through lymphatics? 



22. What happens to foreign particles in the lymph glands and spleen? 

 What other functions have these glands? 



Exercises 



I. How can you see capillaries? Wrap some wet absorbent cotton 

 around the upper part of the body of a goldfish. Tie the fish do\\'n (with 

 a bandage) in a Petri dish and cover its spread-out tail with a glass slide. 

 Examine the edges under low power. Why are the edges best to look at? 

 Do you see motion? Of what does the blood seem to be composed? In 

 what directions does the blood travel? Are the vessels through which 

 blood travels all of the same width? Since you can see the blood inside 

 them what can you conclude about the walls of the capillaries? Does the 

 blood ever stop for a length of time? Does it reverse its direction any- 

 where? 



