Across
- 3. a blood vessel that carries blood away from the heart
- 6. a tiny blood vessel
- 9. the substance in the red blood cells that carries oxygen and gives blood it's red color
- 11. involuntary muscle contractions in the digestive system
- 13. a group of cells with similar functions
- 14. a chemical substance secreted by the endoglands into the bloodstream
- 16. elevated body temperature
- 17. groups of tissues with the same function
Down
- 1. organs that work together to perform special functions
- 2. protection against a disease or condition
- 4. the process of supplying the cells with oxygen and removing carbon dioxide
- 5. the basic unit of body structure
- 7. the burning of food for heat and energy by the cells
- 8. the heart is at rest
- 10. the process that breaks down food physically and chemically
- 12. the heart is pumping blood
- 15. a blood vessel that returns blood to the heart