The Heart

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Across
  1. 3. prevents back-flow from artery
  2. 6. upper left chamber
  3. 7. oxyen-rich blood from lungs
  4. 9. oxygen poor blood to atrium
  5. 11. prevents blood back-flow between ventricle and atrium
  6. 12. upper right chamber
Down
  1. 1. muscle wall between heart
  2. 2. biggest artery
  3. 3. oxygen-poor blood to lungs
  4. 4. left lower chamber
  5. 5. blood to upper body
  6. 8. lower right chamber
  7. 10. prevents back-flow of blood from ventricle