The Circulatory System

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Across
  1. 2. This prevents the backflow of blood
  2. 3. The body's main artery
  3. 6. The left and right sides of the heart are separated by the _______ septum
  4. 9. When ventricles contract and force blood into arteries and parts of the body
  5. 10. A blood vessel that carries blood away from the heart
  6. 12. One of the two upper chambers of the heart
  7. 14. When ventricular muscles relax and expand
Down
  1. 1. Oxygenated blood from lungs enters left atrium through _________ veins
  2. 4. The pulmonary artery carries _________ blood from the heart to the lungs
  3. 5. This stimulates the cardiac muscle to contract
  4. 7. One of the two lower chambers of the heart
  5. 8. This carries oxygen and nutrients to the body's cells
  6. 11. A muscular pumping organ which has four chambers
  7. 13. A vessel that returns blood to the heart