The Circulatory System

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Across
  1. 2. A large vein that carries blood to the heart from other areas of the body.
  2. 5. Blood vessels in the circulatory system that carry oxygen-rich blood away from the heart.
  3. 8. Two upper cavities of the heart from which blood is passed to the ventricles.
  4. 9. Blood vessel that carries oxygen-rich blood from the lungs back to the heart.
  5. 10. A layer of the heart that is a sticky sac-like membrane that surrounds the heart, protecting it and preventing over-expansion.
  6. 12. Also known as a red blood cell, carries oxygen.
  7. 15. The innermost layer of the heart wall, a thin, smooth tissue that lines the heart chambers and valves.
Down
  1. 1. Blood vessel that carries oxygen-poor blood from the right ventricle of the heart to the lungs for oxygenation.
  2. 3. The smallest blood vessels in the body, connecting arterioles to venules.
  3. 4. Two lower cavities of the heart, responsible for pumping blood out of the heart.
  4. 6. Blood vessels in the circulatory system that carry oxygen-poor blood toward the heart.
  5. 7. Also know as a white blood cell, fights off foreign substances and diseases.
  6. 11. The muscular middle layer of that heart.
  7. 13. Also known as a platelet, is involved in blood clotting.
  8. 14. The largest artery in the human body, responsible for carrying oxygen-rich blood from the heart to the rest of the body.