Across
- 2. The muscle underneath the lungs
- 5. A group of cells in the right atrium that control how often the heart beats
- 6. These carry deoxygenated blood back to the heart
- 8. The sugar broken down in respiration
- 10. The capillary wall is _______ cell thick
- 11. The main artery in the body
- 12. The gas we breathe in
Down
- 1. These help prevent backflow
- 3. These take blood away from the heart
- 4. Respiration with oxygen
- 7. The __________ artery and vein connect the heart to the lungs
- 9. When you receive a new heart from someone else to replace your faulty one