Across
- 2. the body’s ability to resist infection
- 4. a substance that triggers immunity to a disease
- 7. the system of glands that release hormones
- 9. a reproductive cell (sperm or egg)
- 11. the process of keeping internal conditions stable
- 13. a type of white blood cell that attacks pathogens
- 16. the joining of sperm and egg
- 17. the gap between neurons where messages pass
- 18. the long fibre that carries nerve impulses away
- 20. a microorganism that causes disease
Down
- 1. the branches of a neuron that receive signals
- 3. a fast automatic response that protects the body
- 5. a chemical messenger made by glands
- 6. the action taken after detecting a stimulus
- 8. a change in the environment that triggers a response
- 10. a cycle that helps maintain balance
- 12. an early stage of human development after fertilisation
- 14. a cell that detects stimuli
- 15. a hormone that lowers blood glucose
- 18. a protein that helps destroy pathogens
- 19. a nerve cell that sends electrical messages