Across
- 1. a reaction to stimulus
- 5. the narrow, winding, upper part of the intestine where digestion is completed and nutrients are absorbed by the blood
- 9. is made up cells that work together to perform a specific function
- 10. organs whose function is to remove carbon dioxide from the blood and provide it with oxygen
- 11. a loop system in which the system responds to positive feedback or negative feedback
- 15. is made up of tissues to perform a specific function
- 16. a natural substance that is produced in the body and that influences the way the body grows or develops
- 18. a sac in the lungs where the exchange of oxygen and carbon dioxide takes place
Down
- 1. receives chemical signals from outside the cell
- 2. the structural and functional unit of the kidney
- 3. carries a signal from one nerve cell to another
- 4. a detectable change in the internal or external environment.
- 6. a nerve cell
- 7. is a molecule that is acted upon by an enzyme
- 8. a hormone produced in the pancreas that regulates the amount of glucose in the blood
- 12. the process of breaking down food
- 13. the process of taking in substances
- 14. the ability of an organism or cell to maintain internal equilibrium
- 17. a large protein which speeds up chemical reactions
- 19. absorbs nutrients in the food