Cardiovascular And Respiratory System

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Across
  1. 4. lymphatic tissue in the nasopharynx
  2. 6. The largest vein in the body
  3. 8. Windpipe
  4. 10. The contraction phase of the heartbeat
  5. 11. The smallest branches of the bronchi
  6. 14. breathing out
  7. 15. Muscular, middle layer of the heart
  8. 17. muscular pump
  9. 18. Double-layered membrane surrounding heart
Down
  1. 1. Inner lining of the heart
  2. 2. The largest type of blood vessel
  3. 3. the pacemaker of the heart
  4. 5. breathing in
  5. 7. The smallest blood vessel
  6. 9. One of two upper chambers of the heart
  7. 12. Voice box
  8. 13. gas that makes up 21% of air
  9. 16. Muscle separating the chest and abdomen