Across
- 4. upper chambers of the heart
- 5. is exchanged for oxygen in the lungs
- 8. lower chambers of the heart
- 11. one complete contraction of the heart
- 12. blood flows into the ______ when it is between beats and relaxed
- 13. our left atrium contracts to pump blood through this valve
Down
- 1. this kind of blood enters the right atrium through the two vena cava veins
- 2. oxygentaed blood enters the left atrium through these veins
- 3. one complete cycle of the three stages
- 6. what does the right atrium do to pump blood through the valves
- 7. our left ventricle contracts to pump blood through this valve
- 9. this kind of blood from our lungs enters the left atrium
- 10. number of heart beats per minute
- 14. where blood is first pumped to exchange gases