Across
- 5. Muscle that aids in breathing by contracting and relaxing (9 letters)
- 7. White blood cells that engulf and digest pathogens (10 letters)
- 9. Protein that carries oxygen in red blood cells (9 letters)
- 10. Cava Main vein returning deoxygenated blood to the heart (9 letters)
- 11. Tiny blood vessels where exchange of nutrients and gases occurs (10 letters)
- 13. Fluid that transports white blood cells and waste products (5 letters)
- 14. First line of immune defense, made of skin and mucous membranes (7 letters)
Down
- 1. Organ that filters blood and recycles red blood cells (6 letters)
- 2. Tube that connects the throat to the lungs (7 letters)
- 3. Nodes Small structures that filter lymph and house immune cells (10 letters)
- 4. Organ where T cells mature
- 6. Flap of tissue that prevents food from entering the trachea (9 letters)
- 8. Microscopic air sacs where gas exchange occurs (7 letters)
- 12. Largest artery in the body (5 letters)