1. The Circulatory System

2. Transportation system by which oxygen and nutrients reach the body's cells, and waste materials are carried away.

3. Also carries substances called hormones, which control body processes, and antibodies to fight invading germs.

4. www.biosbcc.net/doohan/ sample/htm/heart.htm

6. The heart, the lungs, and the blood vessels work together to form the circle part of the circulatory system.

9. http://users.tpg.com.au/users/amcgann/body/circulatory.html

12. sln.fi.edu/biosci/systems/ pulmonary.html

14. http://sln.fi.edu/biosci2/systems/

16. http://sln.fi.edu/biosci/systems/systemic.html

21. http://hes.ucf.k12.pa.us/gclaypo/circdia.html Have strong, muscular walls The inner layer is very smooth so that the blood can flow easily

22. http://sln.fi.edu/biosci/systems/circulation.html

25. http://sln.fi.edu/biosci/systems/circulation.html

26. w3.uokhsc.edu

28. http://hes.ucf.k12.pa.us/gclaypo/circdia.html Valves are located inside the veins. The valves only allow blood to move in one direction.

34. Close up of heart valve Heart sounds are made by the valves as they open and close