Across
- 8. These structures in certain blood vessels prevent the backflow of blood.
- 9. ___ blood is blood filled with low levels of oxygen.
- 10. This process prevents excessive loss of blood when you are injured.
- 12. The red pigment in red blood cells that binds reversibly to oxygen.
- 15. White blood cells have ___ shapes.
Down
- 1. Humans are ____ organisms, so a transport system is required to transport materials quickly to all parts of the body.
- 2. Blood vessel which is only one cell thick.
- 3. Membrane-bound fragments of cytoplasm from bone marrow cells.
- 4. Blood vessel which transports blood away from the heart.
- 5. Red blood cells are destroyed in the _____.
- 6. Red blood cells are produced in the ______.
- 7. One function of blood is to protect the body against _____.
- 11. Pale yellowish liquid which contains 90% water.
- 13. Red blood cells are circular, flattened and ____ in shape to increase surface area to volume ratio for faster diffusion of oxygen.
- 14. Blood vessel which transports blood back into the heart.
