Across
- 5. the blood that transports oxygen
- 7. arteries branch out into these
- 9. ______ circulation is the flow back to the heart
- 10. the heart's lower chamber
- 11. large blood vessels that carry blood away from the heart
- 12. the tough, slippery that encloses the heart
- 13. capillaries merge into these
Down
- 1. the heart's upper chamber
- 2. _____ circulation is transports blood between the heart and the lungs
- 3. the system that includes the heart, veins, and arteries
- 4. the organ that pumps blood to the rest of the body
- 6. arterioles branch out into these
- 8. ______ circulation is the flow of blood to the body except the lungs
- 10. venules carry blood into these
- 12. a straw colored liquid in the blood