Respiratory and Circulatory Systems

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Across
  1. 3. windpipe
  2. 5. muscle that separates the thoracic cavity from the abdominal cavity
  3. 7. passageway for both air and food
  4. 8. one of two branches leading into each lung
  5. 9. occurs when the diaphragm contracts
  6. 12. voice box
  7. 14. vein bringing blood back from the lungs to the heart
  8. 15. largest artery of the body
  9. 17. wall dividing the left and right sides of the heart
  10. 19. tiny air sacs in the lungs
  11. 22. found inside the larynx
  12. 23. pumps blood
  13. 24. substance in blood whose level regulates breathing
  14. 26. bottom chamber of a heart
  15. 27. artery taking blood to the lungs from the heart
Down
  1. 1. flap that blocks the airway when swallowing
  2. 2. protective sac enclosing the heart
  3. 4. large vein entering the heart from the upper body
  4. 6. part of the brain which controls breathing
  5. 10. further divisions of tubes branching off the bronchi
  6. 11. oxygen-carrying molecule in the blood
  7. 13. fluid portion of blood
  8. 14. tiny pieces of cells that help blood clot
  9. 15. top chamber of a heart
  10. 16. side of the heart dealing with deoxygenated blood
  11. 18. small blood vessel where gas exchange takes place
  12. 20. large vein entering the heart from the lower body
  13. 21. white blood cells
  14. 25. red blood cells