1. Do Now What is this person experiencing? A Heart attack Another name for a heart a attack is Angina pectoralis

2. Veins Have valves Low pressure Thin walls (little muscle) Slightly elastic Carry deoxygenated blood Venules – smallest vessel

3. What do valves do? Keep blood from flowing backwards

4. Varicose veins Why does this occur? Because the valves leak.

6. What helps the blood move back to the heart besides the valves in the veins

7. If you go to have your blood drawn do doctors take the blood from a vein or an artery?

8. Arteries have very thick and elastic walls High pressure Arterioles – small arteries Carry oxygenated blood Carry blood away from the heart.

11. Trace a drop of blood through the heart?

13. Gas exchange occurs here