Respiratory & Circulatory Systems

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Across
  1. 5. refers to lungs
  2. 7. small air sacs
  3. 10. bottom chambers of heart
  4. 11. largest artery of heart
  5. 15. protects the lungs
  6. 16. breathing muscle
  7. 20. bronch______
  8. 21. air-filled organs
  9. 22. arteries carry blood ______ from heart
  10. 23. prevents blood flowing backwards
  11. 24. open space inside vessels
  12. 25. cells that carry oxygen
Down
  1. 1. gas needed for survival
  2. 2. carbon _________
  3. 3. helps to stop bleeding
  4. 4. cells that fight infection
  5. 6. carries blood to the heart
  6. 8. entrance chamber of heart
  7. 9. flows through vessels
  8. 12. aka windpipe
  9. 13. high to low concentration
  10. 14. smallest blood vessels
  11. 17. air pipes that split
  12. 18. liquid part of blood
  13. 19. outside of vessel