Across
- 5. The body's natural defense system
- 8. Long tube that moves food from mouth to stomach
- 10. Nerve cell responsible for transmitting signals
- 12. Organ that filters waste from the blood
- 13. Largest organ of the body
- 14. Mature bone cell
- 15. Long bones in the foot
- 19. Brain region controlling the pituitary gland
- 20. Inflammation of the lungs
Down
- 1. Long part of a neuron that transmits signals
- 2. Connects muscle to bone
- 3. Protein that carries oxygen in red blood cells
- 4. Bones that protect the brain
- 6. Gland system that secretes hormones
- 7. Helps fight infections
- 9. Process of maintaining a stable internal environment
- 11. Air sacs in the lungs where gas exchange occurs
- 16. Blood vessels that carry oxygenated blood away from the heart
- 17. Junction between two nerve cells
- 18. Major muscle used for breathing