Across
- 4. These smallest of vessels, have thin walls that allow oxygen, nutrients and wastes to pass through.
- 5. The right side of the heart carries __________ blood to the lungs.
- 6. These blood vessels carry blood towards the heart.
- 7. This protein, found in red blood cells, binds to oxygen.
- 8. These door-like structures make sure that blood flows through the heart in the right direction.
- 10. The movement of blood through your heart and around your body.
- 11. These tiny blood cells are involved in blood clotting.
- 12. The two lower chambers of the heart that receive blood second.
Down
- 1. If Rh factor is present on a red blood cell, it is said to be.
- 2. Another name for the circulatory system is the ____________ system.
- 3. These blood vessels carry blood away from the heart.
- 9. How many major blood groups are there?