The Circulatory System

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Across
  1. 1. fluid that blood is made up of
  2. 6. complex protein
  3. 7. valve between the right ventricle and pulmonary artery
  4. 8. smooth layer of cells that lines the inside of blood vessels
  5. 9. red blood cells
  6. 10. white blood cells
  7. 12. thickest and muscular middle layer
  8. 14. carry blood away from the heart
  9. 15. lower chamber of the heart
  10. 17. blood vessel that connects arterioles with venules
  11. 18. a brief period of rest
Down
  1. 2. a period of ventricular contraction
  2. 3. double-layered membrane that covers the outside of the heart
  3. 4. fragments or pieces of cells
  4. 5. blood vessel that carries blood back to the heart
  5. 11. valve between the left ventricle and aorta
  6. 13. upper chamber of the heart
  7. 16. tissue that flows through the circulatory system
  8. 19. muscular wall that separates the heart