Across
- 3. Tiny air sacs where oxygen and carbon dioxide exchange occurs
- 4. Automatic response to a stimulus without thinking
- 5. Tubes in the lungs that carry air into smaller branches
- 8. Long-term energy storage molecules in the body
- 11. Breaks down food into usable energy for the body
- 13. Organic compounds needed in small amounts for health
- 14. Blood vessel that returns blood to the heart
- 16. Nutrients used to build and repair body tissue
- 17. Bundle of nerves that carries messages between brain and body
- 18. Sugars and starches used for quick energy
- 20. Junction where neurons communicate
- 22. Essential liquid needed for all body functions
Down
- 1. Tiny blood vessels where exchange of materials occurs
- 2. Stores bile for fat digestion
- 5. Control center of the body and nervous system
- 6. Substances in food that the body needs to function and grow
- 7. Organ that produces and releases hormones
- 9. Organ that produces bile to help digest fats
- 10. Inorganic substances like calcium and iron needed by the body
- 12. Fluid in the mouth that begins digestion
- 15. Functional unit of the kidney
- 19. Cell that sends and receives electrical signals in the nervous system
- 21. Vessel that carries blood away from the heart