1. Objective 99: 1

2. 2

3. 3

4. 4

5. 5

6. 6

7. 7

8. 8

9. 9

10. Objective 100: 10

11. Fig. 20-12a. Conducting system of the heart 11

12. Fig. 20-13. Sequence of impulse conduction through the heart. 12

13. Fig. 20-4b. Direction of ventricular fibers twists the heart during contraction. 13

14. Objective 101: 14

15. Fig. 21-2. Elastic and muscular arteries 15

16. Fig. 21-5. Arterioles and capillary bed 16

17. Fig. 21-2. Venules and veins 17

18. Objective 102: 18

19. Fig. 21-6. Valves in the veins promote blood flow back to the heart. 19